Skip to content
Permalink
Branch: master
Find file Copy path
Find file Copy path
Fetching contributors…
Cannot retrieve contributors at this time
4331 lines (3929 sloc) 152 KB
/*
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
#include "Yoga.h"
#include "log.h"
#include <float.h>
#include <string.h>
#include <algorithm>
#include <memory>
#include "Utils.h"
#include "YGNode.h"
#include "YGNodePrint.h"
#include "Yoga-internal.h"
#include "event/event.h"
#ifdef _MSC_VER
#include <float.h>
/* define fmaxf if < VC12 */
#if _MSC_VER < 1800
__forceinline const float fmaxf(const float a, const float b) {
return (a > b) ? a : b;
}
#endif
#endif
using namespace facebook::yoga;
using detail::Log;
#ifdef ANDROID
static int YGAndroidLog(
const YGConfigRef config,
const YGNodeRef node,
YGLogLevel level,
const char* format,
va_list args);
#else
static int YGDefaultLog(
const YGConfigRef config,
const YGNodeRef node,
YGLogLevel level,
const char* format,
va_list args);
#endif
#ifdef ANDROID
#include <android/log.h>
static int YGAndroidLog(
const YGConfigRef config,
const YGNodeRef node,
YGLogLevel level,
const char* format,
va_list args) {
int androidLevel = YGLogLevelDebug;
switch (level) {
case YGLogLevelFatal:
androidLevel = ANDROID_LOG_FATAL;
break;
case YGLogLevelError:
androidLevel = ANDROID_LOG_ERROR;
break;
case YGLogLevelWarn:
androidLevel = ANDROID_LOG_WARN;
break;
case YGLogLevelInfo:
androidLevel = ANDROID_LOG_INFO;
break;
case YGLogLevelDebug:
androidLevel = ANDROID_LOG_DEBUG;
break;
case YGLogLevelVerbose:
androidLevel = ANDROID_LOG_VERBOSE;
break;
}
const int result = __android_log_vprint(androidLevel, "yoga", format, args);
return result;
}
#else
#define YG_UNUSED(x) (void) (x);
static int YGDefaultLog(
const YGConfigRef config,
const YGNodeRef node,
YGLogLevel level,
const char* format,
va_list args) {
YG_UNUSED(config);
YG_UNUSED(node);
switch (level) {
case YGLogLevelError:
case YGLogLevelFatal:
return vfprintf(stderr, format, args);
case YGLogLevelWarn:
case YGLogLevelInfo:
case YGLogLevelDebug:
case YGLogLevelVerbose:
default:
return vprintf(format, args);
}
}
#undef YG_UNUSED
#endif
bool YGFloatIsUndefined(const float value) {
return facebook::yoga::isUndefined(value);
}
detail::CompactValue YGComputedEdgeValue(
const YGStyle::Edges& edges,
YGEdge edge,
detail::CompactValue defaultValue) {
if (!edges[edge].isUndefined()) {
return edges[edge];
}
if ((edge == YGEdgeTop || edge == YGEdgeBottom) &&
!edges[YGEdgeVertical].isUndefined()) {
return edges[YGEdgeVertical];
}
if ((edge == YGEdgeLeft || edge == YGEdgeRight || edge == YGEdgeStart ||
edge == YGEdgeEnd) &&
!edges[YGEdgeHorizontal].isUndefined()) {
return edges[YGEdgeHorizontal];
}
if (!edges[YGEdgeAll].isUndefined()) {
return edges[YGEdgeAll];
}
if (edge == YGEdgeStart || edge == YGEdgeEnd) {
return detail::CompactValue::ofUndefined();
}
return defaultValue;
}
void* YGNodeGetContext(YGNodeRef node) {
return node->getContext();
}
void YGNodeSetContext(YGNodeRef node, void* context) {
return node->setContext(context);
}
bool YGNodeHasMeasureFunc(YGNodeRef node) {
return node->hasMeasureFunc();
}
void YGNodeSetMeasureFunc(YGNodeRef node, YGMeasureFunc measureFunc) {
node->setMeasureFunc(measureFunc);
}
bool YGNodeHasBaselineFunc(YGNodeRef node) {
return node->hasBaselineFunc();
}
void YGNodeSetBaselineFunc(YGNodeRef node, YGBaselineFunc baselineFunc) {
node->setBaselineFunc(baselineFunc);
}
YGDirtiedFunc YGNodeGetDirtiedFunc(YGNodeRef node) {
return node->getDirtied();
}
void YGNodeSetDirtiedFunc(YGNodeRef node, YGDirtiedFunc dirtiedFunc) {
node->setDirtiedFunc(dirtiedFunc);
}
void YGNodeSetPrintFunc(YGNodeRef node, YGPrintFunc printFunc) {
node->setPrintFunc(printFunc);
}
bool YGNodeGetHasNewLayout(YGNodeRef node) {
return node->getHasNewLayout();
}
void YGConfigSetPrintTreeFlag(YGConfigRef config, bool enabled) {
config->printTree = enabled;
}
void YGNodeSetHasNewLayout(YGNodeRef node, bool hasNewLayout) {
node->setHasNewLayout(hasNewLayout);
}
YGNodeType YGNodeGetNodeType(YGNodeRef node) {
return node->getNodeType();
}
void YGNodeSetNodeType(YGNodeRef node, YGNodeType nodeType) {
return node->setNodeType(nodeType);
}
bool YGNodeIsDirty(YGNodeRef node) {
return node->isDirty();
}
bool YGNodeLayoutGetDidUseLegacyFlag(const YGNodeRef node) {
return node->didUseLegacyFlag();
}
void YGNodeMarkDirtyAndPropogateToDescendants(const YGNodeRef node) {
return node->markDirtyAndPropogateDownwards();
}
int32_t gConfigInstanceCount = 0;
WIN_EXPORT YGNodeRef YGNodeNewWithConfig(const YGConfigRef config) {
const YGNodeRef node = new YGNode{config};
YGAssertWithConfig(
config, node != nullptr, "Could not allocate memory for node");
Event::publish<Event::NodeAllocation>(node, {config});
return node;
}
YGConfigRef YGConfigGetDefault() {
static YGConfigRef defaultConfig = YGConfigNew();
return defaultConfig;
}
YGNodeRef YGNodeNew(void) {
return YGNodeNewWithConfig(YGConfigGetDefault());
}
YGNodeRef YGNodeClone(YGNodeRef oldNode) {
YGNodeRef node = new YGNode(*oldNode);
YGAssertWithConfig(
oldNode->getConfig(),
node != nullptr,
"Could not allocate memory for node");
Event::publish<Event::NodeAllocation>(node, {node->getConfig()});
node->setOwner(nullptr);
return node;
}
static YGConfigRef YGConfigClone(const YGConfig& oldConfig) {
const YGConfigRef config = new YGConfig(oldConfig);
YGAssert(config != nullptr, "Could not allocate memory for config");
if (config == nullptr) {
abort();
}
gConfigInstanceCount++;
return config;
}
static YGNodeRef YGNodeDeepClone(YGNodeRef oldNode) {
auto config = YGConfigClone(*oldNode->getConfig());
auto node = new YGNode{*oldNode, config};
node->setOwner(nullptr);
Event::publish<Event::NodeAllocation>(node, {node->getConfig()});
YGVector vec = YGVector();
vec.reserve(oldNode->getChildren().size());
YGNodeRef childNode = nullptr;
for (auto* item : oldNode->getChildren()) {
childNode = YGNodeDeepClone(item);
childNode->setOwner(node);
vec.push_back(childNode);
}
node->setChildren(vec);
return node;
}
void YGNodeFree(const YGNodeRef node) {
if (YGNodeRef owner = node->getOwner()) {
owner->removeChild(node);
node->setOwner(nullptr);
}
const uint32_t childCount = YGNodeGetChildCount(node);
for (uint32_t i = 0; i < childCount; i++) {
const YGNodeRef child = YGNodeGetChild(node, i);
child->setOwner(nullptr);
}
node->clearChildren();
Event::publish<Event::NodeDeallocation>(node, {node->getConfig()});
delete node;
}
static void YGConfigFreeRecursive(const YGNodeRef root) {
if (root->getConfig() != nullptr) {
gConfigInstanceCount--;
delete root->getConfig();
}
// Delete configs recursively for childrens
for (auto* child : root->getChildren()) {
YGConfigFreeRecursive(child);
}
}
void YGNodeFreeRecursiveWithCleanupFunc(
const YGNodeRef root,
YGNodeCleanupFunc cleanup) {
uint32_t skipped = 0;
while (YGNodeGetChildCount(root) > skipped) {
const YGNodeRef child = YGNodeGetChild(root, skipped);
if (child->getOwner() != root) {
// Don't free shared nodes that we don't own.
skipped += 1;
} else {
YGNodeRemoveChild(root, child);
YGNodeFreeRecursive(child);
}
}
if (cleanup != nullptr) {
cleanup(root);
}
YGNodeFree(root);
}
void YGNodeFreeRecursive(const YGNodeRef root) {
return YGNodeFreeRecursiveWithCleanupFunc(root, nullptr);
}
void YGNodeReset(YGNodeRef node) {
node->reset();
}
int32_t YGConfigGetInstanceCount(void) {
return gConfigInstanceCount;
}
YGConfigRef YGConfigNew(void) {
#ifdef ANDROID
const YGConfigRef config = new YGConfig(YGAndroidLog);
#else
const YGConfigRef config = new YGConfig(YGDefaultLog);
#endif
gConfigInstanceCount++;
return config;
}
void YGConfigFree(const YGConfigRef config) {
delete config;
gConfigInstanceCount--;
}
void YGConfigCopy(const YGConfigRef dest, const YGConfigRef src) {
memcpy(dest, src, sizeof(YGConfig));
}
void YGNodeSetIsReferenceBaseline(YGNodeRef node, bool isReferenceBaseline) {
if (node->isReferenceBaseline() != isReferenceBaseline) {
node->setIsReferenceBaseline(isReferenceBaseline);
node->markDirtyAndPropogate();
}
}
bool YGNodeIsReferenceBaseline(YGNodeRef node) {
return node->isReferenceBaseline();
}
void YGNodeInsertChild(
const YGNodeRef owner,
const YGNodeRef child,
const uint32_t index) {
YGAssertWithNode(
owner,
child->getOwner() == nullptr,
"Child already has a owner, it must be removed first.");
YGAssertWithNode(
owner,
!owner->hasMeasureFunc(),
"Cannot add child: Nodes with measure functions cannot have children.");
owner->insertChild(child, index);
child->setOwner(owner);
owner->markDirtyAndPropogate();
}
void YGNodeRemoveChild(const YGNodeRef owner, const YGNodeRef excludedChild) {
if (YGNodeGetChildCount(owner) == 0) {
// This is an empty set. Nothing to remove.
return;
}
// Children may be shared between parents, which is indicated by not having an
// owner. We only want to reset the child completely if it is owned
// exclusively by one node.
auto childOwner = excludedChild->getOwner();
if (owner->removeChild(excludedChild)) {
if (owner == childOwner) {
excludedChild->setLayout({}); // layout is no longer valid
excludedChild->setOwner(nullptr);
}
owner->markDirtyAndPropogate();
}
}
void YGNodeRemoveAllChildren(const YGNodeRef owner) {
const uint32_t childCount = YGNodeGetChildCount(owner);
if (childCount == 0) {
// This is an empty set already. Nothing to do.
return;
}
const YGNodeRef firstChild = YGNodeGetChild(owner, 0);
if (firstChild->getOwner() == owner) {
// If the first child has this node as its owner, we assume that this child
// set is unique.
for (uint32_t i = 0; i < childCount; i++) {
const YGNodeRef oldChild = YGNodeGetChild(owner, i);
oldChild->setLayout(YGNode().getLayout()); // layout is no longer valid
oldChild->setOwner(nullptr);
}
owner->clearChildren();
owner->markDirtyAndPropogate();
return;
}
// Otherwise, we are not the owner of the child set. We don't have to do
// anything to clear it.
owner->setChildren(YGVector());
owner->markDirtyAndPropogate();
}
static void YGNodeSetChildrenInternal(
YGNodeRef const owner,
const std::vector<YGNodeRef>& children) {
if (!owner) {
return;
}
if (children.size() == 0) {
if (YGNodeGetChildCount(owner) > 0) {
for (YGNodeRef const child : owner->getChildren()) {
child->setLayout(YGLayout());
child->setOwner(nullptr);
}
owner->setChildren(YGVector());
owner->markDirtyAndPropogate();
}
} else {
if (YGNodeGetChildCount(owner) > 0) {
for (YGNodeRef const oldChild : owner->getChildren()) {
// Our new children may have nodes in common with the old children. We
// don't reset these common nodes.
if (std::find(children.begin(), children.end(), oldChild) ==
children.end()) {
oldChild->setLayout(YGLayout());
oldChild->setOwner(nullptr);
}
}
}
owner->setChildren(children);
for (YGNodeRef child : children) {
child->setOwner(owner);
}
owner->markDirtyAndPropogate();
}
}
void YGNodeSetChildren(
const YGNodeRef owner,
const YGNodeRef c[],
const uint32_t count) {
const YGVector children = {c, c + count};
YGNodeSetChildrenInternal(owner, children);
}
void YGNodeSetChildren(
YGNodeRef const owner,
const std::vector<YGNodeRef>& children) {
YGNodeSetChildrenInternal(owner, children);
}
YGNodeRef YGNodeGetChild(const YGNodeRef node, const uint32_t index) {
if (index < node->getChildren().size()) {
return node->getChild(index);
}
return nullptr;
}
uint32_t YGNodeGetChildCount(const YGNodeRef node) {
return static_cast<uint32_t>(node->getChildren().size());
}
YGNodeRef YGNodeGetOwner(const YGNodeRef node) {
return node->getOwner();
}
YGNodeRef YGNodeGetParent(const YGNodeRef node) {
return node->getOwner();
}
void YGNodeMarkDirty(const YGNodeRef node) {
YGAssertWithNode(
node,
node->hasMeasureFunc(),
"Only leaf nodes with custom measure functions"
"should manually mark themselves as dirty");
node->markDirtyAndPropogate();
}
void YGNodeCopyStyle(const YGNodeRef dstNode, const YGNodeRef srcNode) {
if (!(dstNode->getStyle() == srcNode->getStyle())) {
dstNode->setStyle(srcNode->getStyle());
dstNode->markDirtyAndPropogate();
}
}
float YGNodeStyleGetFlexGrow(const YGNodeConstRef node) {
return node->getStyle().flexGrow().isUndefined()
? kDefaultFlexGrow
: node->getStyle().flexGrow().unwrap();
}
float YGNodeStyleGetFlexShrink(const YGNodeConstRef node) {
return node->getStyle().flexShrink().isUndefined()
? (node->getConfig()->useWebDefaults ? kWebDefaultFlexShrink
: kDefaultFlexShrink)
: node->getStyle().flexShrink().unwrap();
}
namespace {
template <typename T, typename NeedsUpdate, typename Update>
void updateStyle(
YGNode* node,
T value,
NeedsUpdate&& needsUpdate,
Update&& update) {
if (needsUpdate(node->getStyle(), value)) {
update(node->getStyle(), value);
node->markDirtyAndPropogate();
}
}
template <typename Ref, typename T>
void updateStyle(YGNode* node, Ref (YGStyle::*prop)(), T value) {
updateStyle(
node,
value,
[prop](YGStyle& s, T x) { return (s.*prop)() != x; },
[prop](YGStyle& s, T x) { (s.*prop)() = x; });
}
template <typename Ref, typename Idx>
void updateIndexedStyleProp(
YGNode* node,
Ref (YGStyle::*prop)(),
Idx idx,
detail::CompactValue value) {
using detail::CompactValue;
updateStyle(
node,
value,
[idx, prop](YGStyle& s, CompactValue x) { return (s.*prop)()[idx] != x; },
[idx, prop](YGStyle& s, CompactValue x) { (s.*prop)()[idx] = x; });
}
} // namespace
// MSVC has trouble inferring the return type of pointer to member functions
// with const and non-const overloads, instead of preferring the non-const
// overload like clang and GCC. For the purposes of updateStyle(), we can help
// MSVC by specifying that return type explicitely. In combination with
// decltype, MSVC will prefer the non-const version.
#define MSVC_HINT(PROP) decltype(YGStyle{}.PROP())
void YGNodeStyleSetDirection(const YGNodeRef node, const YGDirection value) {
updateStyle<MSVC_HINT(direction)>(node, &YGStyle::direction, value);
}
YGDirection YGNodeStyleGetDirection(const YGNodeConstRef node) {
return node->getStyle().direction();
}
void YGNodeStyleSetFlexDirection(
const YGNodeRef node,
const YGFlexDirection flexDirection) {
updateStyle<MSVC_HINT(flexDirection)>(
node, &YGStyle::flexDirection, flexDirection);
}
YGFlexDirection YGNodeStyleGetFlexDirection(const YGNodeConstRef node) {
return node->getStyle().flexDirection();
}
void YGNodeStyleSetJustifyContent(
const YGNodeRef node,
const YGJustify justifyContent) {
updateStyle<MSVC_HINT(justifyContent)>(
node, &YGStyle::justifyContent, justifyContent);
}
YGJustify YGNodeStyleGetJustifyContent(const YGNodeConstRef node) {
return node->getStyle().justifyContent();
}
void YGNodeStyleSetAlignContent(
const YGNodeRef node,
const YGAlign alignContent) {
updateStyle<MSVC_HINT(alignContent)>(
node, &YGStyle::alignContent, alignContent);
}
YGAlign YGNodeStyleGetAlignContent(const YGNodeConstRef node) {
return node->getStyle().alignContent();
}
void YGNodeStyleSetAlignItems(const YGNodeRef node, const YGAlign alignItems) {
updateStyle<MSVC_HINT(alignItems)>(node, &YGStyle::alignItems, alignItems);
}
YGAlign YGNodeStyleGetAlignItems(const YGNodeConstRef node) {
return node->getStyle().alignItems();
}
void YGNodeStyleSetAlignSelf(const YGNodeRef node, const YGAlign alignSelf) {
updateStyle<MSVC_HINT(alignSelf)>(node, &YGStyle::alignSelf, alignSelf);
}
YGAlign YGNodeStyleGetAlignSelf(const YGNodeConstRef node) {
return node->getStyle().alignSelf();
}
void YGNodeStyleSetPositionType(
const YGNodeRef node,
const YGPositionType positionType) {
updateStyle<MSVC_HINT(positionType)>(
node, &YGStyle::positionType, positionType);
}
YGPositionType YGNodeStyleGetPositionType(const YGNodeConstRef node) {
return node->getStyle().positionType();
}
void YGNodeStyleSetFlexWrap(const YGNodeRef node, const YGWrap flexWrap) {
updateStyle<MSVC_HINT(flexWrap)>(node, &YGStyle::flexWrap, flexWrap);
}
YGWrap YGNodeStyleGetFlexWrap(const YGNodeConstRef node) {
return node->getStyle().flexWrap();
}
void YGNodeStyleSetOverflow(const YGNodeRef node, const YGOverflow overflow) {
updateStyle<MSVC_HINT(overflow)>(node, &YGStyle::overflow, overflow);
}
YGOverflow YGNodeStyleGetOverflow(const YGNodeConstRef node) {
return node->getStyle().overflow();
}
void YGNodeStyleSetDisplay(const YGNodeRef node, const YGDisplay display) {
updateStyle<MSVC_HINT(display)>(node, &YGStyle::display, display);
}
YGDisplay YGNodeStyleGetDisplay(const YGNodeConstRef node) {
return node->getStyle().display();
}
// TODO(T26792433): Change the API to accept YGFloatOptional.
void YGNodeStyleSetFlex(const YGNodeRef node, const float flex) {
updateStyle<MSVC_HINT(flex)>(node, &YGStyle::flex, YGFloatOptional{flex});
}
// TODO(T26792433): Change the API to accept YGFloatOptional.
float YGNodeStyleGetFlex(const YGNodeConstRef node) {
return node->getStyle().flex().isUndefined()
? YGUndefined
: node->getStyle().flex().unwrap();
}
// TODO(T26792433): Change the API to accept YGFloatOptional.
void YGNodeStyleSetFlexGrow(const YGNodeRef node, const float flexGrow) {
updateStyle<MSVC_HINT(flexGrow)>(
node, &YGStyle::flexGrow, YGFloatOptional{flexGrow});
}
// TODO(T26792433): Change the API to accept YGFloatOptional.
void YGNodeStyleSetFlexShrink(const YGNodeRef node, const float flexShrink) {
updateStyle<MSVC_HINT(flexShrink)>(
node, &YGStyle::flexShrink, YGFloatOptional{flexShrink});
}
YGValue YGNodeStyleGetFlexBasis(const YGNodeConstRef node) {
YGValue flexBasis = node->getStyle().flexBasis();
if (flexBasis.unit == YGUnitUndefined || flexBasis.unit == YGUnitAuto) {
// TODO(T26792433): Get rid off the use of YGUndefined at client side
flexBasis.value = YGUndefined;
}
return flexBasis;
}
void YGNodeStyleSetFlexBasis(const YGNodeRef node, const float flexBasis) {
auto value = detail::CompactValue::ofMaybe<YGUnitPoint>(flexBasis);
updateStyle<MSVC_HINT(flexBasis)>(node, &YGStyle::flexBasis, value);
}
void YGNodeStyleSetFlexBasisPercent(
const YGNodeRef node,
const float flexBasisPercent) {
auto value = detail::CompactValue::ofMaybe<YGUnitPercent>(flexBasisPercent);
updateStyle<MSVC_HINT(flexBasis)>(node, &YGStyle::flexBasis, value);
}
void YGNodeStyleSetFlexBasisAuto(const YGNodeRef node) {
updateStyle<MSVC_HINT(flexBasis)>(
node, &YGStyle::flexBasis, detail::CompactValue::ofAuto());
}
void YGNodeStyleSetPosition(YGNodeRef node, YGEdge edge, float points) {
auto value = detail::CompactValue::ofMaybe<YGUnitPoint>(points);
updateIndexedStyleProp<MSVC_HINT(position)>(
node, &YGStyle::position, edge, value);
}
void YGNodeStyleSetPositionPercent(YGNodeRef node, YGEdge edge, float percent) {
auto value = detail::CompactValue::ofMaybe<YGUnitPercent>(percent);
updateIndexedStyleProp<MSVC_HINT(position)>(
node, &YGStyle::position, edge, value);
}
YGValue YGNodeStyleGetPosition(YGNodeConstRef node, YGEdge edge) {
return node->getStyle().position()[edge];
}
void YGNodeStyleSetMargin(YGNodeRef node, YGEdge edge, float points) {
auto value = detail::CompactValue::ofMaybe<YGUnitPoint>(points);
updateIndexedStyleProp<MSVC_HINT(margin)>(
node, &YGStyle::margin, edge, value);
}
void YGNodeStyleSetMarginPercent(YGNodeRef node, YGEdge edge, float percent) {
auto value = detail::CompactValue::ofMaybe<YGUnitPercent>(percent);
updateIndexedStyleProp<MSVC_HINT(margin)>(
node, &YGStyle::margin, edge, value);
}
void YGNodeStyleSetMarginAuto(YGNodeRef node, YGEdge edge) {
updateIndexedStyleProp<MSVC_HINT(margin)>(
node, &YGStyle::margin, edge, detail::CompactValue::ofAuto());
}
YGValue YGNodeStyleGetMargin(YGNodeConstRef node, YGEdge edge) {
return node->getStyle().margin()[edge];
}
void YGNodeStyleSetPadding(YGNodeRef node, YGEdge edge, float points) {
auto value = detail::CompactValue::ofMaybe<YGUnitPoint>(points);
updateIndexedStyleProp<MSVC_HINT(padding)>(
node, &YGStyle::padding, edge, value);
}
void YGNodeStyleSetPaddingPercent(YGNodeRef node, YGEdge edge, float percent) {
auto value = detail::CompactValue::ofMaybe<YGUnitPercent>(percent);
updateIndexedStyleProp<MSVC_HINT(padding)>(
node, &YGStyle::padding, edge, value);
}
YGValue YGNodeStyleGetPadding(YGNodeConstRef node, YGEdge edge) {
return node->getStyle().padding()[edge];
}
// TODO(T26792433): Change the API to accept YGFloatOptional.
void YGNodeStyleSetBorder(
const YGNodeRef node,
const YGEdge edge,
const float border) {
auto value = detail::CompactValue::ofMaybe<YGUnitPoint>(border);
updateIndexedStyleProp<MSVC_HINT(border)>(
node, &YGStyle::border, edge, value);
}
float YGNodeStyleGetBorder(const YGNodeConstRef node, const YGEdge edge) {
auto border = node->getStyle().border()[edge];
if (border.isUndefined() || border.isAuto()) {
// TODO(T26792433): Rather than returning YGUndefined, change the api to
// return YGFloatOptional.
return YGUndefined;
}
return static_cast<YGValue>(border).value;
}
// Yoga specific properties, not compatible with flexbox specification
// TODO(T26792433): Change the API to accept YGFloatOptional.
float YGNodeStyleGetAspectRatio(const YGNodeConstRef node) {
const YGFloatOptional op = node->getStyle().aspectRatio();
return op.isUndefined() ? YGUndefined : op.unwrap();
}
// TODO(T26792433): Change the API to accept YGFloatOptional.
void YGNodeStyleSetAspectRatio(const YGNodeRef node, const float aspectRatio) {
updateStyle<MSVC_HINT(aspectRatio)>(
node, &YGStyle::aspectRatio, YGFloatOptional{aspectRatio});
}
void YGNodeStyleSetWidth(YGNodeRef node, float points) {
auto value = detail::CompactValue::ofMaybe<YGUnitPoint>(points);
updateIndexedStyleProp<MSVC_HINT(dimensions)>(
node, &YGStyle::dimensions, YGDimensionWidth, value);
}
void YGNodeStyleSetWidthPercent(YGNodeRef node, float percent) {
auto value = detail::CompactValue::ofMaybe<YGUnitPercent>(percent);
updateIndexedStyleProp<MSVC_HINT(dimensions)>(
node, &YGStyle::dimensions, YGDimensionWidth, value);
}
void YGNodeStyleSetWidthAuto(YGNodeRef node) {
updateIndexedStyleProp<MSVC_HINT(dimensions)>(
node,
&YGStyle::dimensions,
YGDimensionWidth,
detail::CompactValue::ofAuto());
}
YGValue YGNodeStyleGetWidth(YGNodeConstRef node) {
return node->getStyle().dimensions()[YGDimensionWidth];
}
void YGNodeStyleSetHeight(YGNodeRef node, float points) {
auto value = detail::CompactValue::ofMaybe<YGUnitPoint>(points);
updateIndexedStyleProp<MSVC_HINT(dimensions)>(
node, &YGStyle::dimensions, YGDimensionHeight, value);
}
void YGNodeStyleSetHeightPercent(YGNodeRef node, float percent) {
auto value = detail::CompactValue::ofMaybe<YGUnitPercent>(percent);
updateIndexedStyleProp<MSVC_HINT(dimensions)>(
node, &YGStyle::dimensions, YGDimensionHeight, value);
}
void YGNodeStyleSetHeightAuto(YGNodeRef node) {
updateIndexedStyleProp<MSVC_HINT(dimensions)>(
node,
&YGStyle::dimensions,
YGDimensionHeight,
detail::CompactValue::ofAuto());
}
YGValue YGNodeStyleGetHeight(YGNodeConstRef node) {
return node->getStyle().dimensions()[YGDimensionHeight];
}
void YGNodeStyleSetMinWidth(const YGNodeRef node, const float minWidth) {
auto value = detail::CompactValue::ofMaybe<YGUnitPoint>(minWidth);
updateIndexedStyleProp<MSVC_HINT(minDimensions)>(
node, &YGStyle::minDimensions, YGDimensionWidth, value);
}
void YGNodeStyleSetMinWidthPercent(const YGNodeRef node, const float minWidth) {
auto value = detail::CompactValue::ofMaybe<YGUnitPercent>(minWidth);
updateIndexedStyleProp<MSVC_HINT(minDimensions)>(
node, &YGStyle::minDimensions, YGDimensionWidth, value);
}
YGValue YGNodeStyleGetMinWidth(const YGNodeConstRef node) {
return node->getStyle().minDimensions()[YGDimensionWidth];
};
void YGNodeStyleSetMinHeight(const YGNodeRef node, const float minHeight) {
auto value = detail::CompactValue::ofMaybe<YGUnitPoint>(minHeight);
updateIndexedStyleProp<MSVC_HINT(minDimensions)>(
node, &YGStyle::minDimensions, YGDimensionHeight, value);
}
void YGNodeStyleSetMinHeightPercent(
const YGNodeRef node,
const float minHeight) {
auto value = detail::CompactValue::ofMaybe<YGUnitPercent>(minHeight);
updateIndexedStyleProp<MSVC_HINT(minDimensions)>(
node, &YGStyle::minDimensions, YGDimensionHeight, value);
}
YGValue YGNodeStyleGetMinHeight(const YGNodeConstRef node) {
return node->getStyle().minDimensions()[YGDimensionHeight];
};
void YGNodeStyleSetMaxWidth(const YGNodeRef node, const float maxWidth) {
auto value = detail::CompactValue::ofMaybe<YGUnitPoint>(maxWidth);
updateIndexedStyleProp<MSVC_HINT(maxDimensions)>(
node, &YGStyle::maxDimensions, YGDimensionWidth, value);
}
void YGNodeStyleSetMaxWidthPercent(const YGNodeRef node, const float maxWidth) {
auto value = detail::CompactValue::ofMaybe<YGUnitPercent>(maxWidth);
updateIndexedStyleProp<MSVC_HINT(maxDimensions)>(
node, &YGStyle::maxDimensions, YGDimensionWidth, value);
}
YGValue YGNodeStyleGetMaxWidth(const YGNodeConstRef node) {
return node->getStyle().maxDimensions()[YGDimensionWidth];
};
void YGNodeStyleSetMaxHeight(const YGNodeRef node, const float maxHeight) {
auto value = detail::CompactValue::ofMaybe<YGUnitPoint>(maxHeight);
updateIndexedStyleProp<MSVC_HINT(maxDimensions)>(
node, &YGStyle::maxDimensions, YGDimensionHeight, value);
}
void YGNodeStyleSetMaxHeightPercent(
const YGNodeRef node,
const float maxHeight) {
auto value = detail::CompactValue::ofMaybe<YGUnitPercent>(maxHeight);
updateIndexedStyleProp<MSVC_HINT(maxDimensions)>(
node, &YGStyle::maxDimensions, YGDimensionHeight, value);
}
YGValue YGNodeStyleGetMaxHeight(const YGNodeConstRef node) {
return node->getStyle().maxDimensions()[YGDimensionHeight];
};
#define YG_NODE_LAYOUT_PROPERTY_IMPL(type, name, instanceName) \
type YGNodeLayoutGet##name(const YGNodeRef node) { \
return node->getLayout().instanceName; \
}
#define YG_NODE_LAYOUT_RESOLVED_PROPERTY_IMPL(type, name, instanceName) \
type YGNodeLayoutGet##name(const YGNodeRef node, const YGEdge edge) { \
YGAssertWithNode( \
node, \
edge <= YGEdgeEnd, \
"Cannot get layout properties of multi-edge shorthands"); \
\
if (edge == YGEdgeStart) { \
if (node->getLayout().direction() == YGDirectionRTL) { \
return node->getLayout().instanceName[YGEdgeRight]; \
} else { \
return node->getLayout().instanceName[YGEdgeLeft]; \
} \
} \
\
if (edge == YGEdgeEnd) { \
if (node->getLayout().direction() == YGDirectionRTL) { \
return node->getLayout().instanceName[YGEdgeLeft]; \
} else { \
return node->getLayout().instanceName[YGEdgeRight]; \
} \
} \
\
return node->getLayout().instanceName[edge]; \
}
YG_NODE_LAYOUT_PROPERTY_IMPL(float, Left, position[YGEdgeLeft]);
YG_NODE_LAYOUT_PROPERTY_IMPL(float, Top, position[YGEdgeTop]);
YG_NODE_LAYOUT_PROPERTY_IMPL(float, Right, position[YGEdgeRight]);
YG_NODE_LAYOUT_PROPERTY_IMPL(float, Bottom, position[YGEdgeBottom]);
YG_NODE_LAYOUT_PROPERTY_IMPL(float, Width, dimensions[YGDimensionWidth]);
YG_NODE_LAYOUT_PROPERTY_IMPL(float, Height, dimensions[YGDimensionHeight]);
YG_NODE_LAYOUT_PROPERTY_IMPL(YGDirection, Direction, direction());
YG_NODE_LAYOUT_PROPERTY_IMPL(bool, HadOverflow, hadOverflow());
YG_NODE_LAYOUT_RESOLVED_PROPERTY_IMPL(float, Margin, margin);
YG_NODE_LAYOUT_RESOLVED_PROPERTY_IMPL(float, Border, border);
YG_NODE_LAYOUT_RESOLVED_PROPERTY_IMPL(float, Padding, padding);
bool YGNodeLayoutGetDidLegacyStretchFlagAffectLayout(const YGNodeRef node) {
return node->getLayout().doesLegacyStretchFlagAffectsLayout();
}
uint32_t gCurrentGenerationCount = 0;
bool YGLayoutNodeInternal(
const YGNodeRef node,
const float availableWidth,
const float availableHeight,
const YGDirection ownerDirection,
const YGMeasureMode widthMeasureMode,
const YGMeasureMode heightMeasureMode,
const float ownerWidth,
const float ownerHeight,
const bool performLayout,
const LayoutPassReason reason,
const YGConfigRef config,
LayoutData& layoutMarkerData,
void* const layoutContext,
const uint32_t depth,
const uint32_t generationCount);
#ifdef DEBUG
static void YGNodePrintInternal(
const YGNodeRef node,
const YGPrintOptions options) {
std::string str;
facebook::yoga::YGNodeToString(str, node, options, 0);
Log::log(node, YGLogLevelDebug, nullptr, str.c_str());
}
void YGNodePrint(const YGNodeRef node, const YGPrintOptions options) {
YGNodePrintInternal(node, options);
}
#endif
const std::array<YGEdge, 4> leading = {
{YGEdgeTop, YGEdgeBottom, YGEdgeLeft, YGEdgeRight}};
const std::array<YGEdge, 4> trailing = {
{YGEdgeBottom, YGEdgeTop, YGEdgeRight, YGEdgeLeft}};
static const std::array<YGEdge, 4> pos = {{
YGEdgeTop,
YGEdgeBottom,
YGEdgeLeft,
YGEdgeRight,
}};
static const std::array<YGDimension, 4> dim = {
{YGDimensionHeight, YGDimensionHeight, YGDimensionWidth, YGDimensionWidth}};
static inline float YGNodePaddingAndBorderForAxis(
const YGNodeConstRef node,
const YGFlexDirection axis,
const float widthSize) {
return (node->getLeadingPaddingAndBorder(axis, widthSize) +
node->getTrailingPaddingAndBorder(axis, widthSize))
.unwrap();
}
static inline YGAlign YGNodeAlignItem(const YGNode* node, const YGNode* child) {
const YGAlign align = child->getStyle().alignSelf() == YGAlignAuto
? node->getStyle().alignItems()
: child->getStyle().alignSelf();
if (align == YGAlignBaseline &&
YGFlexDirectionIsColumn(node->getStyle().flexDirection())) {
return YGAlignFlexStart;
}
return align;
}
static float YGBaseline(const YGNodeRef node, void* layoutContext) {
if (node->hasBaselineFunc()) {
Event::publish<Event::NodeBaselineStart>(node);
const float baseline = node->baseline(
node->getLayout().measuredDimensions[YGDimensionWidth],
node->getLayout().measuredDimensions[YGDimensionHeight],
layoutContext);
Event::publish<Event::NodeBaselineEnd>(node);
YGAssertWithNode(
node,
!YGFloatIsUndefined(baseline),
"Expect custom baseline function to not return NaN");
return baseline;
}
YGNodeRef baselineChild = nullptr;
const uint32_t childCount = YGNodeGetChildCount(node);
for (uint32_t i = 0; i < childCount; i++) {
const YGNodeRef child = YGNodeGetChild(node, i);
if (child->getLineIndex() > 0) {
break;
}
if (child->getStyle().positionType() == YGPositionTypeAbsolute) {
continue;
}
if (YGNodeAlignItem(node, child) == YGAlignBaseline ||
child->isReferenceBaseline()) {
baselineChild = child;
break;
}
if (baselineChild == nullptr) {
baselineChild = child;
}
}
if (baselineChild == nullptr) {
return node->getLayout().measuredDimensions[YGDimensionHeight];
}
const float baseline = YGBaseline(baselineChild, layoutContext);
return baseline + baselineChild->getLayout().position[YGEdgeTop];
}
static bool YGIsBaselineLayout(const YGNodeRef node) {
if (YGFlexDirectionIsColumn(node->getStyle().flexDirection())) {
return false;
}
if (node->getStyle().alignItems() == YGAlignBaseline) {
return true;
}
const uint32_t childCount = YGNodeGetChildCount(node);
for (uint32_t i = 0; i < childCount; i++) {
const YGNodeRef child = YGNodeGetChild(node, i);
if (child->getStyle().positionType() == YGPositionTypeRelative &&
child->getStyle().alignSelf() == YGAlignBaseline) {
return true;
}
}
return false;
}
static inline float YGNodeDimWithMargin(
const YGNodeRef node,
const YGFlexDirection axis,
const float widthSize) {
return node->getLayout().measuredDimensions[dim[axis]] +
(node->getLeadingMargin(axis, widthSize) +
node->getTrailingMargin(axis, widthSize))
.unwrap();
}
static inline bool YGNodeIsStyleDimDefined(
const YGNodeRef node,
const YGFlexDirection axis,
const float ownerSize) {
bool isUndefined =
YGFloatIsUndefined(node->getResolvedDimension(dim[axis]).value);
return !(
node->getResolvedDimension(dim[axis]).unit == YGUnitAuto ||
node->getResolvedDimension(dim[axis]).unit == YGUnitUndefined ||
(node->getResolvedDimension(dim[axis]).unit == YGUnitPoint &&
!isUndefined && node->getResolvedDimension(dim[axis]).value < 0.0f) ||
(node->getResolvedDimension(dim[axis]).unit == YGUnitPercent &&
!isUndefined &&
(node->getResolvedDimension(dim[axis]).value < 0.0f ||
YGFloatIsUndefined(ownerSize))));
}
static inline bool YGNodeIsLayoutDimDefined(
const YGNodeRef node,
const YGFlexDirection axis) {
const float value = node->getLayout().measuredDimensions[dim[axis]];
return !YGFloatIsUndefined(value) && value >= 0.0f;
}
static YGFloatOptional YGNodeBoundAxisWithinMinAndMax(
const YGNodeConstRef node,
const YGFlexDirection axis,
const YGFloatOptional value,
const float axisSize) {
YGFloatOptional min;
YGFloatOptional max;
if (YGFlexDirectionIsColumn(axis)) {
min = YGResolveValue(
node->getStyle().minDimensions()[YGDimensionHeight], axisSize);
max = YGResolveValue(
node->getStyle().maxDimensions()[YGDimensionHeight], axisSize);
} else if (YGFlexDirectionIsRow(axis)) {
min = YGResolveValue(
node->getStyle().minDimensions()[YGDimensionWidth], axisSize);
max = YGResolveValue(
node->getStyle().maxDimensions()[YGDimensionWidth], axisSize);
}
if (max >= YGFloatOptional{0} && value > max) {
return max;
}
if (min >= YGFloatOptional{0} && value < min) {
return min;
}
return value;
}
// Like YGNodeBoundAxisWithinMinAndMax but also ensures that the value doesn't
// go below the padding and border amount.
static inline float YGNodeBoundAxis(
const YGNodeRef node,
const YGFlexDirection axis,
const float value,
const float axisSize,
const float widthSize) {
return YGFloatMax(
YGNodeBoundAxisWithinMinAndMax(
node, axis, YGFloatOptional{value}, axisSize)
.unwrap(),
YGNodePaddingAndBorderForAxis(node, axis, widthSize));
}
static void YGNodeSetChildTrailingPosition(
const YGNodeRef node,
const YGNodeRef child,
const YGFlexDirection axis) {
const float size = child->getLayout().measuredDimensions[dim[axis]];
child->setLayoutPosition(
node->getLayout().measuredDimensions[dim[axis]] - size -
child->getLayout().position[pos[axis]],
trailing[axis]);
}
static void YGConstrainMaxSizeForMode(
const YGNodeConstRef node,
const enum YGFlexDirection axis,
const float ownerAxisSize,
const float ownerWidth,
YGMeasureMode* mode,
float* size) {
const YGFloatOptional maxSize =
YGResolveValue(
node->getStyle().maxDimensions()[dim[axis]], ownerAxisSize) +
YGFloatOptional(node->getMarginForAxis(axis, ownerWidth));
switch (*mode) {
case YGMeasureModeExactly:
case YGMeasureModeAtMost:
*size = (maxSize.isUndefined() || *size < maxSize.unwrap())
? *size
: maxSize.unwrap();
break;
case YGMeasureModeUndefined:
if (!maxSize.isUndefined()) {
*mode = YGMeasureModeAtMost;
*size = maxSize.unwrap();
}
break;
}
}
static void YGNodeComputeFlexBasisForChild(
const YGNodeRef node,
const YGNodeRef child,
const float width,
const YGMeasureMode widthMode,
const float height,
const float ownerWidth,
const float ownerHeight,
const YGMeasureMode heightMode,
const YGDirection direction,
const YGConfigRef config,
LayoutData& layoutMarkerData,
void* const layoutContext,
const uint32_t depth,
const uint32_t generationCount) {
const YGFlexDirection mainAxis =
YGResolveFlexDirection(node->getStyle().flexDirection(), direction);
const bool isMainAxisRow = YGFlexDirectionIsRow(mainAxis);
const float mainAxisSize = isMainAxisRow ? width : height;
const float mainAxisownerSize = isMainAxisRow ? ownerWidth : ownerHeight;
float childWidth;
float childHeight;
YGMeasureMode childWidthMeasureMode;
YGMeasureMode childHeightMeasureMode;
const YGFloatOptional resolvedFlexBasis =
YGResolveValue(child->resolveFlexBasisPtr(), mainAxisownerSize);
const bool isRowStyleDimDefined =
YGNodeIsStyleDimDefined(child, YGFlexDirectionRow, ownerWidth);
const bool isColumnStyleDimDefined =
YGNodeIsStyleDimDefined(child, YGFlexDirectionColumn, ownerHeight);
if (!resolvedFlexBasis.isUndefined() && !YGFloatIsUndefined(mainAxisSize)) {
if (child->getLayout().computedFlexBasis.isUndefined() ||
(YGConfigIsExperimentalFeatureEnabled(
child->getConfig(), YGExperimentalFeatureWebFlexBasis) &&
child->getLayout().computedFlexBasisGeneration != generationCount)) {
const YGFloatOptional paddingAndBorder = YGFloatOptional(
YGNodePaddingAndBorderForAxis(child, mainAxis, ownerWidth));
child->setLayoutComputedFlexBasis(
YGFloatOptionalMax(resolvedFlexBasis, paddingAndBorder));
}
} else if (isMainAxisRow && isRowStyleDimDefined) {
// The width is definite, so use that as the flex basis.
const YGFloatOptional paddingAndBorder = YGFloatOptional(
YGNodePaddingAndBorderForAxis(child, YGFlexDirectionRow, ownerWidth));
child->setLayoutComputedFlexBasis(YGFloatOptionalMax(
YGResolveValue(
child->getResolvedDimensions()[YGDimensionWidth], ownerWidth),
paddingAndBorder));
} else if (!isMainAxisRow && isColumnStyleDimDefined) {
// The height is definite, so use that as the flex basis.
const YGFloatOptional paddingAndBorder =
YGFloatOptional(YGNodePaddingAndBorderForAxis(
child, YGFlexDirectionColumn, ownerWidth));
child->setLayoutComputedFlexBasis(YGFloatOptionalMax(
YGResolveValue(
child->getResolvedDimensions()[YGDimensionHeight], ownerHeight),
paddingAndBorder));
} else {
// Compute the flex basis and hypothetical main size (i.e. the clamped flex
// basis).
childWidth = YGUndefined;
childHeight = YGUndefined;
childWidthMeasureMode = YGMeasureModeUndefined;
childHeightMeasureMode = YGMeasureModeUndefined;
auto marginRow =
child->getMarginForAxis(YGFlexDirectionRow, ownerWidth).unwrap();
auto marginColumn =
child->getMarginForAxis(YGFlexDirectionColumn, ownerWidth).unwrap();
if (isRowStyleDimDefined) {
childWidth =
YGResolveValue(
child->getResolvedDimensions()[YGDimensionWidth], ownerWidth)
.unwrap() +
marginRow;
childWidthMeasureMode = YGMeasureModeExactly;
}
if (isColumnStyleDimDefined) {
childHeight =
YGResolveValue(
child->getResolvedDimensions()[YGDimensionHeight], ownerHeight)
.unwrap() +
marginColumn;
childHeightMeasureMode = YGMeasureModeExactly;
}
// The W3C spec doesn't say anything about the 'overflow' property, but all
// major browsers appear to implement the following logic.
if ((!isMainAxisRow && node->getStyle().overflow() == YGOverflowScroll) ||
node->getStyle().overflow() != YGOverflowScroll) {
if (YGFloatIsUndefined(childWidth) && !YGFloatIsUndefined(width)) {
childWidth = width;
childWidthMeasureMode = YGMeasureModeAtMost;
}
}
if ((isMainAxisRow && node->getStyle().overflow() == YGOverflowScroll) ||
node->getStyle().overflow() != YGOverflowScroll) {
if (YGFloatIsUndefined(childHeight) && !YGFloatIsUndefined(height)) {
childHeight = height;
childHeightMeasureMode = YGMeasureModeAtMost;
}
}
const auto& childStyle = child->getStyle();
if (!childStyle.aspectRatio().isUndefined()) {
if (!isMainAxisRow && childWidthMeasureMode == YGMeasureModeExactly) {
childHeight = marginColumn +
(childWidth - marginRow) / childStyle.aspectRatio().unwrap();
childHeightMeasureMode = YGMeasureModeExactly;
} else if (
isMainAxisRow && childHeightMeasureMode == YGMeasureModeExactly) {
childWidth = marginRow +
(childHeight - marginColumn) * childStyle.aspectRatio().unwrap();
childWidthMeasureMode = YGMeasureModeExactly;
}
}
// If child has no defined size in the cross axis and is set to stretch, set
// the cross axis to be measured exactly with the available inner width
const bool hasExactWidth =
!YGFloatIsUndefined(width) && widthMode == YGMeasureModeExactly;
const bool childWidthStretch =
YGNodeAlignItem(node, child) == YGAlignStretch &&
childWidthMeasureMode != YGMeasureModeExactly;
if (!isMainAxisRow && !isRowStyleDimDefined && hasExactWidth &&
childWidthStretch) {
childWidth = width;
childWidthMeasureMode = YGMeasureModeExactly;
if (!childStyle.aspectRatio().isUndefined()) {
childHeight =
(childWidth - marginRow) / childStyle.aspectRatio().unwrap();
childHeightMeasureMode = YGMeasureModeExactly;
}
}
const bool hasExactHeight =
!YGFloatIsUndefined(height) && heightMode == YGMeasureModeExactly;
const bool childHeightStretch =
YGNodeAlignItem(node, child) == YGAlignStretch &&
childHeightMeasureMode != YGMeasureModeExactly;
if (isMainAxisRow && !isColumnStyleDimDefined && hasExactHeight &&
childHeightStretch) {
childHeight = height;
childHeightMeasureMode = YGMeasureModeExactly;
if (!childStyle.aspectRatio().isUndefined()) {
childWidth =
(childHeight - marginColumn) * childStyle.aspectRatio().unwrap();
childWidthMeasureMode = YGMeasureModeExactly;
}
}
YGConstrainMaxSizeForMode(
child,
YGFlexDirectionRow,
ownerWidth,
ownerWidth,
&childWidthMeasureMode,
&childWidth);
YGConstrainMaxSizeForMode(
child,
YGFlexDirectionColumn,
ownerHeight,
ownerWidth,
&childHeightMeasureMode,
&childHeight);
// Measure the child
YGLayoutNodeInternal(
child,
childWidth,
childHeight,
direction,
childWidthMeasureMode,
childHeightMeasureMode,
ownerWidth,
ownerHeight,
false,
LayoutPassReason::kMeasureChild,
config,
layoutMarkerData,
layoutContext,
depth,
generationCount);
child->setLayoutComputedFlexBasis(YGFloatOptional(YGFloatMax(
child->getLayout().measuredDimensions[dim[mainAxis]],
YGNodePaddingAndBorderForAxis(child, mainAxis, ownerWidth))));
}
child->setLayoutComputedFlexBasisGeneration(generationCount);
}
static void YGNodeAbsoluteLayoutChild(
const YGNodeRef node,
const YGNodeRef child,
const float width,
const YGMeasureMode widthMode,
const float height,
const YGDirection direction,
const YGConfigRef config,
LayoutData& layoutMarkerData,
void* const layoutContext,
const uint32_t depth,
const uint32_t generationCount) {
const YGFlexDirection mainAxis =
YGResolveFlexDirection(node->getStyle().flexDirection(), direction);
const YGFlexDirection crossAxis = YGFlexDirectionCross(mainAxis, direction);
const bool isMainAxisRow = YGFlexDirectionIsRow(mainAxis);
float childWidth = YGUndefined;
float childHeight = YGUndefined;
YGMeasureMode childWidthMeasureMode = YGMeasureModeUndefined;
YGMeasureMode childHeightMeasureMode = YGMeasureModeUndefined;
auto marginRow = child->getMarginForAxis(YGFlexDirectionRow, width).unwrap();
auto marginColumn =
child->getMarginForAxis(YGFlexDirectionColumn, width).unwrap();
if (YGNodeIsStyleDimDefined(child, YGFlexDirectionRow, width)) {
childWidth =
YGResolveValue(child->getResolvedDimensions()[YGDimensionWidth], width)
.unwrap() +
marginRow;
} else {
// If the child doesn't have a specified width, compute the width based on
// the left/right offsets if they're defined.
if (child->isLeadingPositionDefined(YGFlexDirectionRow) &&
child->isTrailingPosDefined(YGFlexDirectionRow)) {
childWidth = node->getLayout().measuredDimensions[YGDimensionWidth] -
(node->getLeadingBorder(YGFlexDirectionRow) +
node->getTrailingBorder(YGFlexDirectionRow)) -
(child->getLeadingPosition(YGFlexDirectionRow, width) +
child->getTrailingPosition(YGFlexDirectionRow, width))
.unwrap();
childWidth =
YGNodeBoundAxis(child, YGFlexDirectionRow, childWidth, width, width);
}
}
if (YGNodeIsStyleDimDefined(child, YGFlexDirectionColumn, height)) {
childHeight = YGResolveValue(
child->getResolvedDimensions()[YGDimensionHeight], height)
.unwrap() +
marginColumn;
} else {
// If the child doesn't have a specified height, compute the height based on
// the top/bottom offsets if they're defined.
if (child->isLeadingPositionDefined(YGFlexDirectionColumn) &&
child->isTrailingPosDefined(YGFlexDirectionColumn)) {
childHeight = node->getLayout().measuredDimensions[YGDimensionHeight] -
(node->getLeadingBorder(YGFlexDirectionColumn) +
node->getTrailingBorder(YGFlexDirectionColumn)) -
(child->getLeadingPosition(YGFlexDirectionColumn, height) +
child->getTrailingPosition(YGFlexDirectionColumn, height))
.unwrap();
childHeight = YGNodeBoundAxis(
child, YGFlexDirectionColumn, childHeight, height, width);
}
}
// Exactly one dimension needs to be defined for us to be able to do aspect
// ratio calculation. One dimension being the anchor and the other being
// flexible.
const auto& childStyle = child->getStyle();
if (YGFloatIsUndefined(childWidth) ^ YGFloatIsUndefined(childHeight)) {
if (!childStyle.aspectRatio().isUndefined()) {
if (YGFloatIsUndefined(childWidth)) {
childWidth = marginRow +
(childHeight - marginColumn) * childStyle.aspectRatio().unwrap();
} else if (YGFloatIsUndefined(childHeight)) {
childHeight = marginColumn +
(childWidth - marginRow) / childStyle.aspectRatio().unwrap();
}
}
}
// If we're still missing one or the other dimension, measure the content.
if (YGFloatIsUndefined(childWidth) || YGFloatIsUndefined(childHeight)) {
childWidthMeasureMode = YGFloatIsUndefined(childWidth)
? YGMeasureModeUndefined
: YGMeasureModeExactly;
childHeightMeasureMode = YGFloatIsUndefined(childHeight)
? YGMeasureModeUndefined
: YGMeasureModeExactly;
// If the size of the owner is defined then try to constrain the absolute
// child to that size as well. This allows text within the absolute child to
// wrap to the size of its owner. This is the same behavior as many browsers
// implement.
if (!isMainAxisRow && YGFloatIsUndefined(childWidth) &&
widthMode != YGMeasureModeUndefined && !YGFloatIsUndefined(width) &&
width > 0) {
childWidth = width;
childWidthMeasureMode = YGMeasureModeAtMost;
}
YGLayoutNodeInternal(
child,
childWidth,
childHeight,
direction,
childWidthMeasureMode,
childHeightMeasureMode,
childWidth,
childHeight,
false,
LayoutPassReason::kAbsMeasureChild,
config,
layoutMarkerData,
layoutContext,
depth,
generationCount);
childWidth = child->getLayout().measuredDimensions[YGDimensionWidth] +
child->getMarginForAxis(YGFlexDirectionRow, width).unwrap();
childHeight = child->getLayout().measuredDimensions[YGDimensionHeight] +
child->getMarginForAxis(YGFlexDirectionColumn, width).unwrap();
}
YGLayoutNodeInternal(
child,
childWidth,
childHeight,
direction,
YGMeasureModeExactly,
YGMeasureModeExactly,
childWidth,
childHeight,
true,
LayoutPassReason::kAbsLayout,
config,
layoutMarkerData,
layoutContext,
depth,
generationCount);
if (child->isTrailingPosDefined(mainAxis) &&
!child->isLeadingPositionDefined(mainAxis)) {
child->setLayoutPosition(
node->getLayout().measuredDimensions[dim[mainAxis]] -
child->getLayout().measuredDimensions[dim[mainAxis]] -
node->getTrailingBorder(mainAxis) -
child->getTrailingMargin(mainAxis, width).unwrap() -
child->getTrailingPosition(mainAxis, isMainAxisRow ? width : height)
.unwrap(),
leading[mainAxis]);
} else if (
!child->isLeadingPositionDefined(mainAxis) &&
node->getStyle().justifyContent() == YGJustifyCenter) {
child->setLayoutPosition(
(node->getLayout().measuredDimensions[dim[mainAxis]] -
child->getLayout().measuredDimensions[dim[mainAxis]]) /
2.0f,
leading[mainAxis]);
} else if (
!child->isLeadingPositionDefined(mainAxis) &&
node->getStyle().justifyContent() == YGJustifyFlexEnd) {
child->setLayoutPosition(
(node->getLayout().measuredDimensions[dim[mainAxis]] -
child->getLayout().measuredDimensions[dim[mainAxis]]),
leading[mainAxis]);
}
if (child->isTrailingPosDefined(crossAxis) &&
!child->isLeadingPositionDefined(crossAxis)) {
child->setLayoutPosition(
node->getLayout().measuredDimensions[dim[crossAxis]] -
child->getLayout().measuredDimensions[dim[crossAxis]] -
node->getTrailingBorder(crossAxis) -
child->getTrailingMargin(crossAxis, width).unwrap() -
child
->getTrailingPosition(crossAxis, isMainAxisRow ? height : width)
.unwrap(),
leading[crossAxis]);
} else if (
!child->isLeadingPositionDefined(crossAxis) &&
YGNodeAlignItem(node, child) == YGAlignCenter) {
child->setLayoutPosition(
(node->getLayout().measuredDimensions[dim[crossAxis]] -
child->getLayout().measuredDimensions[dim[crossAxis]]) /
2.0f,
leading[crossAxis]);
} else if (
!child->isLeadingPositionDefined(crossAxis) &&
((YGNodeAlignItem(node, child) == YGAlignFlexEnd) ^
(node->getStyle().flexWrap() == YGWrapWrapReverse))) {
child->setLayoutPosition(
(node->getLayout().measuredDimensions[dim[crossAxis]] -
child->getLayout().measuredDimensions[dim[crossAxis]]),
leading[crossAxis]);
}
}
static void YGNodeWithMeasureFuncSetMeasuredDimensions(
const YGNodeRef node,
const float availableWidth,
const float availableHeight,
const YGMeasureMode widthMeasureMode,
const YGMeasureMode heightMeasureMode,
const float ownerWidth,
const float ownerHeight,
LayoutData& layoutMarkerData,
void* const layoutContext,
const LayoutPassReason reason) {
YGAssertWithNode(
node,
node->hasMeasureFunc(),
"Expected node to have custom measure function");
const float paddingAndBorderAxisRow =
YGNodePaddingAndBorderForAxis(node, YGFlexDirectionRow, availableWidth);
const float paddingAndBorderAxisColumn = YGNodePaddingAndBorderForAxis(
node, YGFlexDirectionColumn, availableWidth);
const float marginAxisRow =
node->getMarginForAxis(YGFlexDirectionRow, availableWidth).unwrap();
const float marginAxisColumn =
node->getMarginForAxis(YGFlexDirectionColumn, availableWidth).unwrap();
// We want to make sure we don't call measure with negative size
const float innerWidth = YGFloatIsUndefined(availableWidth)
? availableWidth
: YGFloatMax(0, availableWidth - marginAxisRow - paddingAndBorderAxisRow);
const float innerHeight = YGFloatIsUndefined(availableHeight)
? availableHeight
: YGFloatMax(
0, availableHeight - marginAxisColumn - paddingAndBorderAxisColumn);
if (widthMeasureMode == YGMeasureModeExactly &&
heightMeasureMode == YGMeasureModeExactly) {
// Don't bother sizing the text if both dimensions are already defined.
node->setLayoutMeasuredDimension(
YGNodeBoundAxis(
node,
YGFlexDirectionRow,
availableWidth - marginAxisRow,
ownerWidth,
ownerWidth),
YGDimensionWidth);
node->setLayoutMeasuredDimension(
YGNodeBoundAxis(
node,
YGFlexDirectionColumn,
availableHeight - marginAxisColumn,
ownerHeight,
ownerWidth),
YGDimensionHeight);
} else {
Event::publish<Event::MeasureCallbackStart>(node);
// Measure the text under the current constraints.
const YGSize measuredSize = node->measure(
innerWidth,
widthMeasureMode,
innerHeight,
heightMeasureMode,
layoutContext);
layoutMarkerData.measureCallbacks += 1;
layoutMarkerData.measureCallbackReasonsCount[static_cast<size_t>(reason)] +=
1;
Event::publish<Event::MeasureCallbackEnd>(
node,
{layoutContext,
innerWidth,
widthMeasureMode,
innerHeight,
heightMeasureMode,
measuredSize.width,
measuredSize.height,
reason});
node->setLayoutMeasuredDimension(
YGNodeBoundAxis(
node,
YGFlexDirectionRow,
(widthMeasureMode == YGMeasureModeUndefined ||
widthMeasureMode == YGMeasureModeAtMost)
? measuredSize.width + paddingAndBorderAxisRow
: availableWidth - marginAxisRow,
ownerWidth,
ownerWidth),
YGDimensionWidth);
node->setLayoutMeasuredDimension(
YGNodeBoundAxis(
node,
YGFlexDirectionColumn,
(heightMeasureMode == YGMeasureModeUndefined ||
heightMeasureMode == YGMeasureModeAtMost)
? measuredSize.height + paddingAndBorderAxisColumn
: availableHeight - marginAxisColumn,
ownerHeight,
ownerWidth),
YGDimensionHeight);
}
}
// For nodes with no children, use the available values if they were provided,
// or the minimum size as indicated by the padding and border sizes.
static void YGNodeEmptyContainerSetMeasuredDimensions(
const YGNodeRef node,
const float availableWidth,
const float availableHeight,
const YGMeasureMode widthMeasureMode,
const YGMeasureMode heightMeasureMode,
const float ownerWidth,
const float ownerHeight) {
const float paddingAndBorderAxisRow =
YGNodePaddingAndBorderForAxis(node, YGFlexDirectionRow, ownerWidth);
const float paddingAndBorderAxisColumn =
YGNodePaddingAndBorderForAxis(node, YGFlexDirectionColumn, ownerWidth);
const float marginAxisRow =
node->getMarginForAxis(YGFlexDirectionRow, ownerWidth).unwrap();
const float marginAxisColumn =
node->getMarginForAxis(YGFlexDirectionColumn, ownerWidth).unwrap();
node->setLayoutMeasuredDimension(
YGNodeBoundAxis(
node,
YGFlexDirectionRow,
(widthMeasureMode == YGMeasureModeUndefined ||
widthMeasureMode == YGMeasureModeAtMost)
? paddingAndBorderAxisRow
: availableWidth - marginAxisRow,
ownerWidth,
ownerWidth),
YGDimensionWidth);
node->setLayoutMeasuredDimension(
YGNodeBoundAxis(
node,
YGFlexDirectionColumn,
(heightMeasureMode == YGMeasureModeUndefined ||
heightMeasureMode == YGMeasureModeAtMost)
? paddingAndBorderAxisColumn
: availableHeight - marginAxisColumn,
ownerHeight,
ownerWidth),
YGDimensionHeight);
}
static bool YGNodeFixedSizeSetMeasuredDimensions(
const YGNodeRef node,
const float availableWidth,
const float availableHeight,
const YGMeasureMode widthMeasureMode,
const YGMeasureMode heightMeasureMode,
const float ownerWidth,
const float ownerHeight) {
if ((!YGFloatIsUndefined(availableWidth) &&
widthMeasureMode == YGMeasureModeAtMost && availableWidth <= 0.0f) ||
(!YGFloatIsUndefined(availableHeight) &&
heightMeasureMode == YGMeasureModeAtMost && availableHeight <= 0.0f) ||
(widthMeasureMode == YGMeasureModeExactly &&
heightMeasureMode == YGMeasureModeExactly)) {
auto marginAxisColumn =
node->getMarginForAxis(YGFlexDirectionColumn, ownerWidth).unwrap();
auto marginAxisRow =
node->getMarginForAxis(YGFlexDirectionRow, ownerWidth).unwrap();
node->setLayoutMeasuredDimension(
YGNodeBoundAxis(
node,
YGFlexDirectionRow,
YGFloatIsUndefined(availableWidth) ||
(widthMeasureMode == YGMeasureModeAtMost &&
availableWidth < 0.0f)
? 0.0f
: availableWidth - marginAxisRow,
ownerWidth,
ownerWidth),
YGDimensionWidth);
node->setLayoutMeasuredDimension(
YGNodeBoundAxis(
node,
YGFlexDirectionColumn,
YGFloatIsUndefined(availableHeight) ||
(heightMeasureMode == YGMeasureModeAtMost &&
availableHeight < 0.0f)
? 0.0f
: availableHeight - marginAxisColumn,
ownerHeight,
ownerWidth),
YGDimensionHeight);
return true;
}
return false;
}
static void YGZeroOutLayoutRecursivly(
const YGNodeRef node,
void* layoutContext) {
node->getLayout() = {};
node->setLayoutDimension(0, 0);
node->setLayoutDimension(0, 1);
node->setHasNewLayout(true);
node->iterChildrenAfterCloningIfNeeded(
YGZeroOutLayoutRecursivly, layoutContext);
}
static float YGNodeCalculateAvailableInnerDim(
const YGNodeConstRef node,
YGFlexDirection axis,
float availableDim,
float ownerDim) {
YGFlexDirection direction =
YGFlexDirectionIsRow(axis) ? YGFlexDirectionRow : YGFlexDirectionColumn;
YGDimension dimension =
YGFlexDirectionIsRow(axis) ? YGDimensionWidth : YGDimensionHeight;
const float margin = node->getMarginForAxis(direction, ownerDim).unwrap();
const float paddingAndBorder =
YGNodePaddingAndBorderForAxis(node, direction, ownerDim);
float availableInnerDim = availableDim - margin - paddingAndBorder;
// Max dimension overrides predefined dimension value; Min dimension in turn
// overrides both of the above
if (!YGFloatIsUndefined(availableInnerDim)) {
// We want to make sure our available height does not violate min and max
// constraints
const YGFloatOptional minDimensionOptional =
YGResolveValue(node->getStyle().minDimensions()[dimension], ownerDim);
const float minInnerDim = minDimensionOptional.isUndefined()
? 0.0f
: minDimensionOptional.unwrap() - paddingAndBorder;
const YGFloatOptional maxDimensionOptional =
YGResolveValue(node->getStyle().maxDimensions()[dimension], ownerDim);
const float maxInnerDim = maxDimensionOptional.isUndefined()
? FLT_MAX
: maxDimensionOptional.unwrap() - paddingAndBorder;
availableInnerDim =
YGFloatMax(YGFloatMin(availableInnerDim, maxInnerDim), minInnerDim);
}
return availableInnerDim;
}
static float YGNodeComputeFlexBasisForChildren(
const YGNodeRef node,
const float availableInnerWidth,
const float availableInnerHeight,
YGMeasureMode widthMeasureMode,
YGMeasureMode heightMeasureMode,
YGDirection direction,
YGFlexDirection mainAxis,
const YGConfigRef config,
bool performLayout,
LayoutData& layoutMarkerData,
void* const layoutContext,
const uint32_t depth,
const uint32_t generationCount) {
float totalOuterFlexBasis = 0.0f;
YGNodeRef singleFlexChild = nullptr;
const YGVector &children = node->getChildren();
YGMeasureMode measureModeMainDim =
YGFlexDirectionIsRow(mainAxis) ? widthMeasureMode : heightMeasureMode;
// If there is only one child with flexGrow + flexShrink it means we can set
// the computedFlexBasis to 0 instead of measuring and shrinking / flexing the
// child to exactly match the remaining space
if (measureModeMainDim == YGMeasureModeExactly) {
for (auto child : children) {
if (child->isNodeFlexible()) {
if (singleFlexChild != nullptr ||
YGFloatsEqual(child->resolveFlexGrow(), 0.0f) ||
YGFloatsEqual(child->resolveFlexShrink(), 0.0f)) {
// There is already a flexible child, or this flexible child doesn't
// have flexGrow and flexShrink, abort
singleFlexChild = nullptr;
break;
} else {
singleFlexChild = child;
}
}
}
}
for (auto child : children) {
child->resolveDimension();
if (child->getStyle().display() == YGDisplayNone) {
YGZeroOutLayoutRecursivly(child, layoutContext);
child->setHasNewLayout(true);
child->setDirty(false);
continue;
}
if (performLayout) {
// Set the initial position (relative to the owner).
const YGDirection childDirection = child->resolveDirection(direction);
const float mainDim = YGFlexDirectionIsRow(mainAxis)
? availableInnerWidth
: availableInnerHeight;
const float crossDim = YGFlexDirectionIsRow(mainAxis)
? availableInnerHeight
: availableInnerWidth;
child->setPosition(
childDirection, mainDim, crossDim, availableInnerWidth);
}
if (child->getStyle().positionType() == YGPositionTypeAbsolute) {
continue;
}
if (child == singleFlexChild) {
child->setLayoutComputedFlexBasisGeneration(generationCount);
child->setLayoutComputedFlexBasis(YGFloatOptional(0));
} else {
YGNodeComputeFlexBasisForChild(
node,
child,
availableInnerWidth,
widthMeasureMode,
availableInnerHeight,
availableInnerWidth,
availableInnerHeight,
heightMeasureMode,
direction,
config,
layoutMarkerData,
layoutContext,
depth,
generationCount);
}
totalOuterFlexBasis +=
(child->getLayout().computedFlexBasis +
child->getMarginForAxis(mainAxis, availableInnerWidth))
.unwrap();
}
return totalOuterFlexBasis;
}
// This function assumes that all the children of node have their
// computedFlexBasis properly computed(To do this use
// YGNodeComputeFlexBasisForChildren function). This function calculates
// YGCollectFlexItemsRowMeasurement
static YGCollectFlexItemsRowValues YGCalculateCollectFlexItemsRowValues(
const YGNodeRef& node,
const YGDirection ownerDirection,
const float mainAxisownerSize,
const float availableInnerWidth,
const float availableInnerMainDim,
const uint32_t startOfLineIndex,
const uint32_t lineCount) {
YGCollectFlexItemsRowValues flexAlgoRowMeasurement = {};
flexAlgoRowMeasurement.relativeChildren.reserve(node->getChildren().size());
float sizeConsumedOnCurrentLineIncludingMinConstraint = 0;
const YGFlexDirection mainAxis = YGResolveFlexDirection(
node->getStyle().flexDirection(), node->resolveDirection(ownerDirection));
const bool isNodeFlexWrap = node->getStyle().flexWrap() != YGWrapNoWrap;
// Add items to the current line until it's full or we run out of items.
uint32_t endOfLineIndex = startOfLineIndex;
for (; endOfLineIndex < node->getChildren().size(); endOfLineIndex++) {
const YGNodeRef child = node->getChild(endOfLineIndex);
if (child->getStyle().display() == YGDisplayNone ||
child->getStyle().positionType() == YGPositionTypeAbsolute) {
continue;
}
child->setLineIndex(lineCount);
const float childMarginMainAxis =
child->getMarginForAxis(mainAxis, availableInnerWidth).unwrap();
const float flexBasisWithMinAndMaxConstraints =
YGNodeBoundAxisWithinMinAndMax(
child,
mainAxis,
child->getLayout().computedFlexBasis,
mainAxisownerSize)
.unwrap();
// If this is a multi-line flow and this item pushes us over the available
// size, we've hit the end of the current line. Break out of the loop and
// lay out the current line.
if (sizeConsumedOnCurrentLineIncludingMinConstraint +
flexBasisWithMinAndMaxConstraints + childMarginMainAxis >
availableInnerMainDim &&
isNodeFlexWrap && flexAlgoRowMeasurement.itemsOnLine > 0) {
break;
}
sizeConsumedOnCurrentLineIncludingMinConstraint +=
flexBasisWithMinAndMaxConstraints + childMarginMainAxis;
flexAlgoRowMeasurement.sizeConsumedOnCurrentLine +=
flexBasisWithMinAndMaxConstraints + childMarginMainAxis;
flexAlgoRowMeasurement.itemsOnLine++;
if (child->isNodeFlexible()) {
flexAlgoRowMeasurement.totalFlexGrowFactors += child->resolveFlexGrow();
// Unlike the grow factor, the shrink factor is scaled relative to the
// child dimension.
flexAlgoRowMeasurement.totalFlexShrinkScaledFactors +=
-child->resolveFlexShrink() *
child->getLayout().computedFlexBasis.unwrap();
}
flexAlgoRowMeasurement.relativeChildren.push_back(child);
}
// The total flex factor needs to be floored to 1.
if (flexAlgoRowMeasurement.totalFlexGrowFactors > 0 &&
flexAlgoRowMeasurement.totalFlexGrowFactors < 1) {
flexAlgoRowMeasurement.totalFlexGrowFactors = 1;
}
// The total flex shrink factor needs to be floored to 1.
if (flexAlgoRowMeasurement.totalFlexShrinkScaledFactors > 0 &&
flexAlgoRowMeasurement.totalFlexShrinkScaledFactors < 1) {
flexAlgoRowMeasurement.totalFlexShrinkScaledFactors = 1;
}
flexAlgoRowMeasurement.endOfLineIndex = endOfLineIndex;
return flexAlgoRowMeasurement;
}
// It distributes the free space to the flexible items and ensures that the size
// of the flex items abide the min and max constraints. At the end of this
// function the child nodes would have proper size. Prior using this function
// please ensure that YGDistributeFreeSpaceFirstPass is called.
static float YGDistributeFreeSpaceSecondPass(
YGCollectFlexItemsRowValues& collectedFlexItemsValues,
const YGNodeRef node,
const YGFlexDirection mainAxis,
const YGFlexDirection crossAxis,
const float mainAxisownerSize,
const float availableInnerMainDim,
const float availableInnerCrossDim,
const float availableInnerWidth,
const float availableInnerHeight,
const bool flexBasisOverflows,
const YGMeasureMode measureModeCrossDim,
const bool performLayout,
const YGConfigRef config,
LayoutData& layoutMarkerData,
void* const layoutContext,
const uint32_t depth,
const uint32_t generationCount) {
float childFlexBasis = 0;
float flexShrinkScaledFactor = 0;
float flexGrowFactor = 0;
float deltaFreeSpace = 0;
const bool isMainAxisRow = YGFlexDirectionIsRow(mainAxis);
const bool isNodeFlexWrap = node->getStyle().flexWrap() != YGWrapNoWrap;
for (auto currentRelativeChild : collectedFlexItemsValues.relativeChildren) {
childFlexBasis = YGNodeBoundAxisWithinMinAndMax(
currentRelativeChild,
mainAxis,
currentRelativeChild->getLayout().computedFlexBasis,
mainAxisownerSize)
.unwrap();
float updatedMainSize = childFlexBasis;
if (!YGFloatIsUndefined(collectedFlexItemsValues.remainingFreeSpace) &&
collectedFlexItemsValues.remainingFreeSpace < 0) {
flexShrinkScaledFactor =
-currentRelativeChild->resolveFlexShrink() * childFlexBasis;
// Is this child able to shrink?
if (flexShrinkScaledFactor != 0) {
float childSize;
if (!YGFloatIsUndefined(
collectedFlexItemsValues.totalFlexShrinkScaledFactors) &&
collectedFlexItemsValues.totalFlexShrinkScaledFactors == 0) {
childSize = childFlexBasis + flexShrinkScaledFactor;
} else {
childSize = childFlexBasis +
(collectedFlexItemsValues.remainingFreeSpace /
collectedFlexItemsValues.totalFlexShrinkScaledFactors) *
flexShrinkScaledFactor;
}
updatedMainSize = YGNodeBoundAxis(
currentRelativeChild,
mainAxis,
childSize,
availableInnerMainDim,
availableInnerWidth);
}
} else if (
!YGFloatIsUndefined(collectedFlexItemsValues.remainingFreeSpace) &&
collectedFlexItemsValues.remainingFreeSpace > 0) {
flexGrowFactor = currentRelativeChild->resolveFlexGrow();
// Is this child able to grow?
if (!YGFloatIsUndefined(flexGrowFactor) && flexGrowFactor != 0) {
updatedMainSize = YGNodeBoundAxis(
currentRelativeChild,
mainAxis,
childFlexBasis +
collectedFlexItemsValues.remainingFreeSpace /
collectedFlexItemsValues.totalFlexGrowFactors *
flexGrowFactor,
availableInnerMainDim,
availableInnerWidth);
}
}
deltaFreeSpace += updatedMainSize - childFlexBasis;
const float marginMain =
currentRelativeChild->getMarginForAxis(mainAxis, availableInnerWidth)
.unwrap();
const float marginCross =
currentRelativeChild->getMarginForAxis(crossAxis, availableInnerWidth)
.unwrap();
float childCrossSize;
float childMainSize = updatedMainSize + marginMain;
YGMeasureMode childCrossMeasureMode;
YGMeasureMode childMainMeasureMode = YGMeasureModeExactly;
const auto& childStyle = currentRelativeChild->getStyle();
if (!childStyle.aspectRatio().isUndefined()) {
childCrossSize = isMainAxisRow
? (childMainSize - marginMain) / childStyle.aspectRatio().unwrap()
: (childMainSize - marginMain) * childStyle.aspectRatio().unwrap();
childCrossMeasureMode = YGMeasureModeExactly;
childCrossSize += marginCross;
} else if (
!YGFloatIsUndefined(availableInnerCrossDim) &&
!YGNodeIsStyleDimDefined(
currentRelativeChild, crossAxis, availableInnerCrossDim) &&
measureModeCrossDim == YGMeasureModeExactly &&
!(isNodeFlexWrap && flexBasisOverflows) &&
YGNodeAlignItem(node, currentRelativeChild) == YGAlignStretch &&
currentRelativeChild->marginLeadingValue(crossAxis).unit !=
YGUnitAuto &&
currentRelativeChild->marginTrailingValue(crossAxis).unit !=
YGUnitAuto) {
childCrossSize = availableInnerCrossDim;
childCrossMeasureMode = YGMeasureModeExactly;
} else if (!YGNodeIsStyleDimDefined(
currentRelativeChild, crossAxis, availableInnerCrossDim)) {
childCrossSize = availableInnerCrossDim;
childCrossMeasureMode = YGFloatIsUndefined(childCrossSize)
? YGMeasureModeUndefined
: YGMeasureModeAtMost;
} else {
childCrossSize =
YGResolveValue(
currentRelativeChild->getResolvedDimension(dim[crossAxis]),
availableInnerCrossDim)
.unwrap() +
marginCross;
const bool isLoosePercentageMeasurement =
currentRelativeChild->getResolvedDimension(dim[crossAxis]).unit ==
YGUnitPercent &&
measureModeCrossDim != YGMeasureModeExactly;
childCrossMeasureMode =
YGFloatIsUndefined(childCrossSize) || isLoosePercentageMeasurement
? YGMeasureModeUndefined
: YGMeasureModeExactly;
}
YGConstrainMaxSizeForMode(
currentRelativeChild,
mainAxis,
availableInnerMainDim,
availableInnerWidth,
&childMainMeasureMode,
&childMainSize);
YGConstrainMaxSizeForMode(
currentRelativeChild,
crossAxis,
availableInnerCrossDim,
availableInnerWidth,
&childCrossMeasureMode,
&childCrossSize);
const bool requiresStretchLayout =
!YGNodeIsStyleDimDefined(
currentRelativeChild, crossAxis, availableInnerCrossDim) &&
YGNodeAlignItem(node, currentRelativeChild) == YGAlignStretch &&
currentRelativeChild->marginLeadingValue(crossAxis).unit !=
YGUnitAuto &&
currentRelativeChild->marginTrailingValue(crossAxis).unit != YGUnitAuto;
const float childWidth = isMainAxisRow ? childMainSize : childCrossSize;
const float childHeight = !isMainAxisRow ? childMainSize : childCrossSize;
const YGMeasureMode childWidthMeasureMode =
isMainAxisRow ? childMainMeasureMode : childCrossMeasureMode;
const YGMeasureMode childHeightMeasureMode =
!isMainAxisRow ? childMainMeasureMode : childCrossMeasureMode;
const bool isLayoutPass = performLayout && !requiresStretchLayout;
// Recursively call the layout algorithm for this child with the updated
// main size.
YGLayoutNodeInternal(
currentRelativeChild,
childWidth,
childHeight,
node->getLayout().direction(),
childWidthMeasureMode,
childHeightMeasureMode,
availableInnerWidth,
availableInnerHeight,
isLayoutPass,
isLayoutPass ? LayoutPassReason::kFlexLayout
: LayoutPassReason::kFlexMeasure,
config,
layoutMarkerData,
layoutContext,
depth,
generationCount);
node->setLayoutHadOverflow(
node->getLayout().hadOverflow() |
currentRelativeChild->getLayout().hadOverflow());
}
return deltaFreeSpace;
}
// It distributes the free space to the flexible items.For those flexible items
// whose min and max constraints are triggered, those flex item's clamped size
// is removed from the remaingfreespace.
static void YGDistributeFreeSpaceFirstPass(
YGCollectFlexItemsRowValues& collectedFlexItemsValues,
const YGFlexDirection mainAxis,
const float mainAxisownerSize,
const float availableInnerMainDim,
const float availableInnerWidth) {
float flexShrinkScaledFactor = 0;
float flexGrowFactor = 0;
float baseMainSize = 0;
float boundMainSize = 0;
float deltaFreeSpace = 0;
for (auto currentRelativeChild : collectedFlexItemsValues.relativeChildren) {
float childFlexBasis =
YGNodeBoundAxisWithinMinAndMax(
currentRelativeChild,
mainAxis,
currentRelativeChild->getLayout().computedFlexBasis,
mainAxisownerSize)
.unwrap();
if (collectedFlexItemsValues.remainingFreeSpace < 0) {
flexShrinkScaledFactor =
-currentRelativeChild->resolveFlexShrink() * childFlexBasis;
// Is this child able to shrink?
if (!YGFloatIsUndefined(flexShrinkScaledFactor) &&
flexShrinkScaledFactor != 0) {
baseMainSize = childFlexBasis +
collectedFlexItemsValues.remainingFreeSpace /
collectedFlexItemsValues.totalFlexShrinkScaledFactors *
flexShrinkScaledFactor;
boundMainSize = YGNodeBoundAxis(
currentRelativeChild,
mainAxis,
baseMainSize,
availableInnerMainDim,
availableInnerWidth);
if (!YGFloatIsUndefined(baseMainSize) &&
!YGFloatIsUndefined(boundMainSize) &&
baseMainSize != boundMainSize) {
// By excluding this item's size and flex factor from remaining, this
// item's min/max constraints should also trigger in the second pass
// resulting in the item's size calculation being identical in the
// first and second passes.
deltaFreeSpace += boundMainSize - childFlexBasis;
collectedFlexItemsValues.totalFlexShrinkScaledFactors -=
flexShrinkScaledFactor;
}
}
} else if (
!YGFloatIsUndefined(collectedFlexItemsValues.remainingFreeSpace) &&
collectedFlexItemsValues.remainingFreeSpace > 0) {
flexGrowFactor = currentRelativeChild->resolveFlexGrow();
// Is this child able to grow?
if (!YGFloatIsUndefined(flexGrowFactor) && flexGrowFactor != 0) {
baseMainSize = childFlexBasis +
collectedFlexItemsValues.remainingFreeSpace /
collectedFlexItemsValues.totalFlexGrowFactors * flexGrowFactor;
boundMainSize = YGNodeBoundAxis(
currentRelativeChild,
mainAxis,
baseMainSize,
availableInnerMainDim,
availableInnerWidth);
if (!YGFloatIsUndefined(baseMainSize) &&
!YGFloatIsUndefined(boundMainSize) &&
baseMainSize != boundMainSize) {
// By excluding this item's size and flex factor from remaining, this
// item's min/max constraints should also trigger in the second pass
// resulting in the item's size calculation being identical in the
// first and second passes.
deltaFreeSpace += boundMainSize - childFlexBasis;
collectedFlexItemsValues.totalFlexGrowFactors -= flexGrowFactor;
}
}
}
}
collectedFlexItemsValues.remainingFreeSpace -= deltaFreeSpace;
}
// Do two passes over the flex items to figure out how to distribute the
// remaining space.
//
// The first pass finds the items whose min/max constraints trigger, freezes
// them at those sizes, and excludes those sizes from the remaining space.
//
// The second pass sets the size of each flexible item. It distributes the
// remaining space amongst the items whose min/max constraints didn't trigger in
// the first pass. For the other items, it sets their sizes by forcing their
// min/max constraints to trigger again.
//
// This two pass approach for resolving min/max constraints deviates from the
// spec. The spec
// (https://www.w3.org/TR/CSS-flexbox-1/#resolve-flexible-lengths) describes a
// process that needs to be repeated a variable number of times. The algorithm
// implemented here won't handle all cases but it was simpler to implement and
// it mitigates performance concerns because we know exactly how many passes
// it'll do.
//
// At the end of this function the child nodes would have the proper size
// assigned to them.
//
static void YGResolveFlexibleLength(
const YGNodeRef node,
YGCollectFlexItemsRowValues& collectedFlexItemsValues,
const YGFlexDirection mainAxis,
const YGFlexDirection crossAxis,
const float mainAxisownerSize,
const float availableInnerMainDim,
const float availableInnerCrossDim,
const float availableInnerWidth,
const float availableInnerHeight,
const bool flexBasisOverflows,
const YGMeasureMode measureModeCrossDim,
const bool performLayout,
const YGConfigRef config,
LayoutData& layoutMarkerData,
void* const layoutContext,
const uint32_t depth,
const uint32_t generationCount) {
const float originalFreeSpace = collectedFlexItemsValues.remainingFreeSpace;
// First pass: detect the flex items whose min/max constraints trigger
YGDistributeFreeSpaceFirstPass(
collectedFlexItemsValues,
mainAxis,
mainAxisownerSize,
availableInnerMainDim,
availableInnerWidth);
// Second pass: resolve the sizes of the flexible items
const float distributedFreeSpace = YGDistributeFreeSpaceSecondPass(
collectedFlexItemsValues,
node,
mainAxis,
crossAxis,
mainAxisownerSize,
availableInnerMainDim,
availableInnerCrossDim,
availableInnerWidth,
availableInnerHeight,
flexBasisOverflows,
measureModeCrossDim,
performLayout,
config,
layoutMarkerData,
layoutContext,
depth,
generationCount);
collectedFlexItemsValues.remainingFreeSpace =
originalFreeSpace - distributedFreeSpace;
}
static void YGJustifyMainAxis(
const YGNodeRef node,
YGCollectFlexItemsRowValues& collectedFlexItemsValues,
const uint32_t startOfLineIndex,
const YGFlexDirection mainAxis,
const YGFlexDirection crossAxis,
const YGMeasureMode measureModeMainDim,
const YGMeasureMode measureModeCrossDim,
const float mainAxisownerSize,
const float ownerWidth,
const float availableInnerMainDim,
const float availableInnerCrossDim,
const float availableInnerWidth,
const bool performLayout,
void* const layoutContext) {
const auto& style = node->getStyle();
const float leadingPaddingAndBorderMain =
node->getLeadingPaddingAndBorder(mainAxis, ownerWidth).unwrap();
const float trailingPaddingAndBorderMain =
node->getTrailingPaddingAndBorder(mainAxis, ownerWidth).unwrap();
// If we are using "at most" rules in the main axis, make sure that
// remainingFreeSpace is 0 when min main dimension is not given
if (measureModeMainDim == YGMeasureModeAtMost &&
collectedFlexItemsValues.remainingFreeSpace > 0) {
if (!style.minDimensions()[dim[mainAxis]].isUndefined() &&
!YGResolveValue(style.minDimensions()[dim[mainAxis]], mainAxisownerSize)
.isUndefined()) {
// This condition makes sure that if the size of main dimension(after
// considering child nodes main dim, leading and trailing padding etc)
// falls below min dimension, then the remainingFreeSpace is reassigned
// considering the min dimension
// `minAvailableMainDim` denotes minimum available space in which child
// can be laid out, it will exclude space consumed by padding and border.
const float minAvailableMainDim =
YGResolveValue(
style.minDimensions()[dim[mainAxis]], mainAxisownerSize)
.unwrap() -
leadingPaddingAndBorderMain - trailingPaddingAndBorderMain;
const float occupiedSpaceByChildNodes =
availableInnerMainDim - collectedFlexItemsValues.remainingFreeSpace;
collectedFlexItemsValues.remainingFreeSpace =
YGFloatMax(0, minAvailableMainDim - occupiedSpaceByChildNodes);
} else {
collectedFlexItemsValues.remainingFreeSpace = 0;
}
}
int numberOfAutoMarginsOnCurrentLine = 0;
for (uint32_t i = startOfLineIndex;
i < collectedFlexItemsValues.endOfLineIndex;
i++) {
const YGNodeRef child = node->getChild(i);
if (child->getStyle().positionType() == YGPositionTypeRelative) {
if (child->marginLeadingValue(mainAxis).unit == YGUnitAuto) {
numberOfAutoMarginsOnCurrentLine++;
}
if (child->marginTrailingValue(mainAxis).unit == YGUnitAuto) {
numberOfAutoMarginsOnCurrentLine++;
}
}
}
// In order to position the elements in the main axis, we have two controls.
// The space between the beginning and the first element and the space between
// each two elements.
float leadingMainDim = 0;
float betweenMainDim = 0;
const YGJustify justifyContent = node->getStyle().justifyContent();
if (numberOfAutoMarginsOnCurrentLine == 0) {
switch (justifyContent) {
case YGJustifyCenter:
leadingMainDim = collectedFlexItemsValues.remainingFreeSpace / 2;
break;
case YGJustifyFlexEnd:
leadingMainDim = collectedFlexItemsValues.remainingFreeSpace;
break;
case YGJustifySpaceBetween:
if (collectedFlexItemsValues.itemsOnLine > 1) {
betweenMainDim =
YGFloatMax(collectedFlexItemsValues.remainingFreeSpace, 0) /
(collectedFlexItemsValues.itemsOnLine - 1);
} else {
betweenMainDim = 0;
}
break;
case YGJustifySpaceEvenly:
// Space is distributed evenly across all elements
betweenMainDim = collectedFlexItemsValues.remainingFreeSpace /
(collectedFlexItemsValues.itemsOnLine + 1);
leadingMainDim = betweenMainDim;
break;
case YGJustifySpaceAround:
// Space on the edges is half of the space between elements
betweenMainDim = collectedFlexItemsValues.remainingFreeSpace /
collectedFlexItemsValues.itemsOnLine;
leadingMainDim = betweenMainDim / 2;
break;
case YGJustifyFlexStart:
break;
}
}
collectedFlexItemsValues.mainDim =
leadingPaddingAndBorderMain + leadingMainDim;
collectedFlexItemsValues.crossDim = 0;
float maxAscentForCurrentLine = 0;
float maxDescentForCurrentLine = 0;
bool isNodeBaselineLayout = YGIsBaselineLayout(node);
for (uint32_t i = startOfLineIndex;
i < collectedFlexItemsValues.endOfLineIndex;
i++) {
const YGNodeRef child = node->getChild(i);
const YGStyle& childStyle = child->getStyle();
const YGLayout childLayout = child->getLayout();
if (childStyle.display() == YGDisplayNone) {
continue;
}
if (childStyle.positionType() == YGPositionTypeAbsolute &&
child->isLeadingPositionDefined(mainAxis)) {
if (performLayout) {
// In case the child is position absolute and has left/top being
// defined, we override the position to whatever the user said (and
// margin/border).
child->setLayoutPosition(
child->getLeadingPosition(mainAxis, availableInnerMainDim)
.unwrap() +
node->getLeadingBorder(mainAxis) +
child->getLeadingMargin(mainAxis, availableInnerWidth).unwrap(),
pos[mainAxis]);
}
} else {
// Now that we placed the element, we need to update the variables.
// We need to do that only for relative elements. Absolute elements do not
// take part in that phase.
if (childStyle.positionType() == YGPositionTypeRelative) {
if (child->marginLeadingValue(mainAxis).unit == YGUnitAuto) {
collectedFlexItemsValues.mainDim +=
collectedFlexItemsValues.remainingFreeSpace /
numberOfAutoMarginsOnCurrentLine;
}
if (performLayout) {
child->setLayoutPosition(
childLayout.position[pos[mainAxis]] +
collectedFlexItemsValues.mainDim,
pos[mainAxis]);
}
if (child->marginTrailingValue(mainAxis).unit == YGUnitAuto) {
collectedFlexItemsValues.mainDim +=
collectedFlexItemsValues.remainingFreeSpace /
numberOfAutoMarginsOnCurrentLine;
}
bool canSkipFlex =
!performLayout && measureModeCrossDim == YGMeasureModeExactly;
if (canSkipFlex) {
// If we skipped the flex step, then we can't rely on the measuredDims
// because they weren't computed. This means we can't call
// YGNodeDimWithMargin.
collectedFlexItemsValues.mainDim += betweenMainDim +
child->getMarginForAxis(mainAxis, availableInnerWidth).unwrap() +
childLayout.computedFlexBasis.unwrap();
collectedFlexItemsValues.crossDim = availableInnerCrossDim;
} else {
// The main dimension is the sum of all the elements dimension plus
// the spacing.
collectedFlexItemsValues.mainDim += betweenMainDim +
YGNodeDimWithMargin(child, mainAxis, availableInnerWidth);
if (isNodeBaselineLayout) {
// If the child is baseline aligned then the cross dimension is
// calculated by adding maxAscent and maxDescent from the baseline.
const float ascent = YGBaseline(child, layoutContext) +
child
->getLeadingMargin(
YGFlexDirectionColumn, availableInnerWidth)
.unwrap();
const float descent =
child->getLayout().measuredDimensions[YGDimensionHeight] +
child
->getMarginForAxis(
YGFlexDirectionColumn, availableInnerWidth)
.unwrap() -
ascent;
maxAscentForCurrentLine =
YGFloatMax(maxAscentForCurrentLine, ascent);
maxDescentForCurrentLine =
YGFloatMax(maxDescentForCurrentLine, descent);
} else {
// The cross dimension is the max of the elements dimension since
// there can only be one element in that cross dimension in the case
// when the items are not baseline aligned
collectedFlexItemsValues.crossDim = YGFloatMax(
collectedFlexItemsValues.crossDim,
YGNodeDimWithMargin(child, crossAxis, availableInnerWidth));
}
}
} else if (performLayout) {
child->setLayoutPosition(
childLayout.position[pos[mainAxis]] +
node->getLeadingBorder(mainAxis) + leadingMainDim,
pos[mainAxis]);
}
}
}
collectedFlexItemsValues.mainDim += trailingPaddingAndBorderMain;
if (isNodeBaselineLayout) {
collectedFlexItemsValues.crossDim =
maxAscentForCurrentLine + maxDescentForCurrentLine;
}
}
//
// This is the main routine that implements a subset of the flexbox layout
// algorithm described in the W3C CSS documentation:
// https://www.w3.org/TR/CSS3-flexbox/.
//
// Limitations of this algorithm, compared to the full standard:
// * Display property is always assumed to be 'flex' except for Text nodes,
// which are assumed to be 'inline-flex'.
// * The 'zIndex' property (or any form of z ordering) is not supported. Nodes
// are stacked in document order.
// * The 'order' property is not supported. The order of flex items is always
// defined by document order.
// * The 'visibility' property is always assumed to be 'visible'. Values of
// 'collapse' and 'hidden' are not supported.
// * There is no support for forced breaks.
// * It does not support vertical inline directions (top-to-bottom or
// bottom-to-top text).
//
// Deviations from standard:
// * Section 4.5 of the spec indicates that all flex items have a default
// minimum main size. For text blocks, for example, this is the width of the
// widest word. Calculating the minimum width is expensive, so we forego it
// and assume a default minimum main size of 0.
// * Min/Max sizes in the main axis are not honored when resolving flexible
// lengths.
// * The spec indicates that the default value for 'flexDirection' is 'row',
// but the algorithm below assumes a default of 'column'.
//
// Input parameters:
// - node: current node to be sized and layed out
// - availableWidth & availableHeight: available size to be used for sizing
// the node or YGUndefined if the size is not available; interpretation
// depends on layout flags
// - ownerDirection: the inline (text) direction within the owner
// (left-to-right or right-to-left)
// - widthMeasureMode: indicates the sizing rules for the width (see below
// for explanation)
// - heightMeasureMode: indicates the sizing rules for the height (see below
// for explanation)
// - performLayout: specifies whether the caller is interested in just the
// dimensions of the node or it requires the entire node and its subtree to
// be layed out (with final positions)
//
// Details:
// This routine is called recursively to lay out subtrees of flexbox
// elements. It uses the information in node.style, which is treated as a
// read-only input. It is responsible for setting the layout.direction and
// layout.measuredDimensions fields for the input node as well as the
// layout.position and layout.lineIndex fields for its child nodes. The
// layout.measuredDimensions field includes any border or padding for the
// node but does not include margins.
//
// The spec describes four different layout modes: "fill available", "max
// content", "min content", and "fit content". Of these, we don't use "min
// content" because we don't support default minimum main sizes (see above
// for details). Each of our measure modes maps to a layout mode from the
// spec (https://www.w3.org/TR/CSS3-sizing/#terms):
// - YGMeasureModeUndefined: max content
// - YGMeasureModeExactly: fill available
// - YGMeasureModeAtMost: fit content
//
// When calling YGNodelayoutImpl and YGLayoutNodeInternal, if the caller
// passes an available size of undefined then it must also pass a measure
// mode of YGMeasureModeUndefined in that dimension.
//
static void YGNodelayoutImpl(
const YGNodeRef node,
const float availableWidth,
const float availableHeight,
const YGDirection ownerDirection,
const YGMeasureMode widthMeasureMode,
const YGMeasureMode heightMeasureMode,
const float ownerWidth,
const float ownerHeight,
const bool performLayout,
const YGConfigRef config,
LayoutData& layoutMarkerData,
void* const layoutContext,
const uint32_t depth,
const uint32_t generationCount,
const LayoutPassReason reason) {
YGAssertWithNode(
node,
YGFloatIsUndefined(availableWidth)
? widthMeasureMode == YGMeasureModeUndefined
: true,
"availableWidth is indefinite so widthMeasureMode must be "
"YGMeasureModeUndefined");
YGAssertWithNode(
node,
YGFloatIsUndefined(availableHeight)
? heightMeasureMode == YGMeasureModeUndefined
: true,
"availableHeight is indefinite so heightMeasureMode must be "
"YGMeasureModeUndefined");
(performLayout ? layoutMarkerData.layouts : layoutMarkerData.measures) += 1;
// Set the resolved resolution in the node's layout.
const YGDirection direction = node->resolveDirection(ownerDirection);
node->setLayoutDirection(direction);
const YGFlexDirection flexRowDirection =
YGResolveFlexDirection(YGFlexDirectionRow, direction);
const YGFlexDirection flexColumnDirection =
YGResolveFlexDirection(YGFlexDirectionColumn, direction);
const YGEdge startEdge =
direction == YGDirectionLTR ? YGEdgeLeft : YGEdgeRight;
const YGEdge endEdge = direction == YGDirectionLTR ? YGEdgeRight : YGEdgeLeft;
node->setLayoutMargin(
node->getLeadingMargin(flexRowDirection, ownerWidth).unwrap(), startEdge);
node->setLayoutMargin(
node->getTrailingMargin(flexRowDirection, ownerWidth).unwrap(), endEdge);
node->setLayoutMargin(
node->getLeadingMargin(flexColumnDirection, ownerWidth).unwrap(),
YGEdgeTop);
node->setLayoutMargin(
node->getTrailingMargin(flexColumnDirection, ownerWidth).unwrap(),
YGEdgeBottom);
node->setLayoutBorder(node->getLeadingBorder(flexRowDirection), startEdge);
node->setLayoutBorder(node->getTrailingBorder(flexRowDirection), endEdge);
node->setLayoutBorder(node->getLeadingBorder(flexColumnDirection), YGEdgeTop);
node->setLayoutBorder(
node->getTrailingBorder(flexColumnDirection), YGEdgeBottom);
node->setLayoutPadding(
node->getLeadingPadding(flexRowDirection, ownerWidth).unwrap(),
startEdge);
node->setLayoutPadding(
node->getTrailingPadding(flexRowDirection, ownerWidth).unwrap(), endEdge);
node->setLayoutPadding(
node->getLeadingPadding(flexColumnDirection, ownerWidth).unwrap(),
YGEdgeTop);
node->setLayoutPadding(
node->getTrailingPadding(flexColumnDirection, ownerWidth).unwrap(),
YGEdgeBottom);
if (node->hasMeasureFunc()) {
YGNodeWithMeasureFuncSetMeasuredDimensions(
node,
availableWidth,
availableHeight,
widthMeasureMode,
heightMeasureMode,
ownerWidth,
ownerHeight,
layoutMarkerData,
layoutContext,
reason);
return;
}
const uint32_t childCount = YGNodeGetChildCount(node);
if (childCount == 0) {
YGNodeEmptyContainerSetMeasuredDimensions(
node,
availableWidth,
availableHeight,
widthMeasureMode,
heightMeasureMode,
ownerWidth,
ownerHeight);
return;
}
// If we're not being asked to perform a full layout we can skip the algorithm
// if we already know the size
if (!performLayout &&
YGNodeFixedSizeSetMeasuredDimensions(
node,
availableWidth,
availableHeight,
widthMeasureMode,
heightMeasureMode,
ownerWidth,
ownerHeight)) {
return;
}
// At this point we know we're going to perform work. Ensure that each child
// has a mutable copy.
node->cloneChildrenIfNeeded(layoutContext);
// Reset layout flags, as they could have changed.
node->setLayoutHadOverflow(false);
// STEP 1: CALCULATE VALUES FOR REMAINDER OF ALGORITHM
const YGFlexDirection mainAxis =
YGResolveFlexDirection(node->getStyle().flexDirection(), direction);
const YGFlexDirection crossAxis = YGFlexDirectionCross(mainAxis, direction);
const bool isMainAxisRow = YGFlexDirectionIsRow(mainAxis);
const bool isNodeFlexWrap = node->getStyle().flexWrap() != YGWrapNoWrap;
const float mainAxisownerSize = isMainAxisRow ? ownerWidth : ownerHeight;
const float crossAxisownerSize = isMainAxisRow ? ownerHeight : ownerWidth;
const float leadingPaddingAndBorderCross =
node->getLeadingPaddingAndBorder(crossAxis, ownerWidth).unwrap();
const float paddingAndBorderAxisMain =
YGNodePaddingAndBorderForAxis(node, mainAxis, ownerWidth);
const float paddingAndBorderAxisCross =
YGNodePaddingAndBorderForAxis(node, crossAxis, ownerWidth);
YGMeasureMode measureModeMainDim =
isMainAxisRow ? widthMeasureMode : heightMeasureMode;
YGMeasureMode measureModeCrossDim =
isMainAxisRow ? heightMeasureMode : widthMeasureMode;
const float paddingAndBorderAxisRow =
isMainAxisRow ? paddingAndBorderAxisMain : paddingAndBorderAxisCross;
const float paddingAndBorderAxisColumn =
isMainAxisRow ? paddingAndBorderAxisCross : paddingAndBorderAxisMain;
const float marginAxisRow =
node->getMarginForAxis(YGFlexDirectionRow, ownerWidth).unwrap();
const float marginAxisColumn =
node->getMarginForAxis(YGFlexDirectionColumn, ownerWidth).unwrap();
const auto& minDimensions = node->getStyle().minDimensions();
const auto& maxDimensions = node->getStyle().maxDimensions();
const float minInnerWidth =
YGResolveValue(minDimensions[YGDimensionWidth], ownerWidth).unwrap() -
paddingAndBorderAxisRow;
const float maxInnerWidth =
YGResolveValue(maxDimensions[YGDimensionWidth], ownerWidth).unwrap() -
paddingAndBorderAxisRow;
const float minInnerHeight =
YGResolveValue(minDimensions[YGDimensionHeight], ownerHeight).unwrap() -
paddingAndBorderAxisColumn;
const float maxInnerHeight =
YGResolveValue(maxDimensions[YGDimensionHeight], ownerHeight).unwrap() -
paddingAndBorderAxisColumn;
const float minInnerMainDim = isMainAxisRow ? minInnerWidth : minInnerHeight;
const float maxInnerMainDim = isMainAxisRow ? maxInnerWidth : maxInnerHeight;
// STEP 2: DETERMINE AVAILABLE SIZE IN MAIN AND CROSS DIRECTIONS
float availableInnerWidth = YGNodeCalculateAvailableInnerDim(
node, YGFlexDirectionRow, availableWidth, ownerWidth);
float availableInnerHeight = YGNodeCalculateAvailableInnerDim(
node, YGFlexDirectionColumn, availableHeight, ownerHeight);
float availableInnerMainDim =
isMainAxisRow ? availableInnerWidth : availableInnerHeight;
const float availableInnerCrossDim =
isMainAxisRow ? availableInnerHeight : availableInnerWidth;
// STEP 3: DETERMINE FLEX BASIS FOR EACH ITEM
float totalOuterFlexBasis = YGNodeComputeFlexBasisForChildren(
node,
availableInnerWidth,
availableInnerHeight,
widthMeasureMode,
heightMeasureMode,
direction,
mainAxis,
config,
performLayout,
layoutMarkerData,
layoutContext,
depth,
generationCount);
const bool flexBasisOverflows = measureModeMainDim == YGMeasureModeUndefined
? false
: totalOuterFlexBasis > availableInnerMainDim;
if (isNodeFlexWrap && flexBasisOverflows &&
measureModeMainDim == YGMeasureModeAtMost) {
measureModeMainDim = YGMeasureModeExactly;
}
// STEP 4: COLLECT FLEX ITEMS INTO FLEX LINES
// Indexes of children that represent the first and last items in the line.
uint32_t startOfLineIndex = 0;
uint32_t endOfLineIndex = 0;
// Number of lines.
uint32_t lineCount = 0;
// Accumulated cross dimensions of all lines so far.
float totalLineCrossDim = 0;
// Max main dimension of all the lines.
float maxLineMainDim = 0;
YGCollectFlexItemsRowValues collectedFlexItemsValues;
for (; endOfLineIndex < childCount;
lineCount++, startOfLineIndex = endOfLineIndex) {
collectedFlexItemsValues = YGCalculateCollectFlexItemsRowValues(
node,
ownerDirection,
mainAxisownerSize,
availableInnerWidth,
availableInnerMainDim,
startOfLineIndex,
lineCount);
endOfLineIndex = collectedFlexItemsValues.endOfLineIndex;
// If we don't need to measure the cross axis, we can skip the entire flex
// step.
const bool canSkipFlex =
!performLayout && measureModeCrossDim == YGMeasureModeExactly;
// STEP 5: RESOLVING FLEXIBLE LENGTHS ON MAIN AXIS
// Calculate the remaining available space that needs to be allocated. If
// the main dimension size isn't known, it is computed based on the line
// length, so there's no more space left to distribute.
bool sizeBasedOnContent = false;
// If we don't measure with exact main dimension we want to ensure we don't
// violate min and max
if (measureModeMainDim != YGMeasureModeExactly) {
if (!YGFloatIsUndefined(minInnerMainDim) &&
collectedFlexItemsValues.sizeConsumedOnCurrentLine <
minInnerMainDim) {
availableInnerMainDim = minInnerMainDim;
} else if (
!YGFloatIsUndefined(maxInnerMainDim) &&
collectedFlexItemsValues.sizeConsumedOnCurrentLine >
maxInnerMainDim) {
availableInnerMainDim = maxInnerMainDim;
} else {
if (!node->getConfig()->useLegacyStretchBehaviour &&
((YGFloatIsUndefined(
collectedFlexItemsValues.totalFlexGrowFactors) &&
collectedFlexItemsValues.totalFlexGrowFactors == 0) ||
(YGFloatIsUndefined(node->resolveFlexGrow()) &&
node->resolveFlexGrow() == 0))) {
// If we don't have any children to flex or we can't flex the node
// itself, space we've used is all space we need. Root node also
// should be shrunk to minimum
availableInnerMainDim =
collectedFlexItemsValues.sizeConsumedOnCurrentLine;
}
if (node->getConfig()->useLegacyStretchBehaviour) {
node->setLayoutDidUseLegacyFlag(true);
}
sizeBasedOnContent = !node->getConfig()->useLegacyStretchBehaviour;
}
}
if (!sizeBasedOnContent && !YGFloatIsUndefined(availableInnerMainDim)) {
collectedFlexItemsValues.remainingFreeSpace = availableInnerMainDim -
collectedFlexItemsValues.sizeConsumedOnCurrentLine;
} else if (collectedFlexItemsValues.sizeConsumedOnCurrentLine < 0) {
// availableInnerMainDim is indefinite which means the node is being sized
// based on its content. sizeConsumedOnCurrentLine is negative which means
// the node will allocate 0 points for its content. Consequently,
// remainingFreeSpace is 0 - sizeConsumedOnCurrentLine.
collectedFlexItemsValues.remainingFreeSpace =
-collectedFlexItemsValues.sizeConsumedOnCurrentLine;
}
if (!canSkipFlex) {
YGResolveFlexibleLength(
node,
collectedFlexItemsValues,
mainAxis,
crossAxis,
mainAxisownerSize,
availableInnerMainDim,
availableInnerCrossDim,
availableInnerWidth,
availableInnerHeight,
flexBasisOverflows,
measureModeCrossDim,
performLayout,
config,
layoutMarkerData,
layoutContext,
depth,
generationCount);
}
node->setLayoutHadOverflow(
node->getLayout().hadOverflow() |
(collectedFlexItemsValues.remainingFreeSpace < 0));
// STEP 6: MAIN-AXIS JUSTIFICATION & CROSS-AXIS SIZE DETERMINATION
// At this point, all the children have their dimensions set in the main
// axis. Their dimensions are also set in the cross axis with the exception
// of items that are aligned "stretch". We need to compute these stretch
// values and set the final positions.
YGJustifyMainAxis(
node,
collectedFlexItemsValues,
startOfLineIndex,
mainAxis,
crossAxis,
measureModeMainDim,
measureModeCrossDim,
mainAxisownerSize,
ownerWidth,
availableInnerMainDim,
availableInnerCrossDim,
availableInnerWidth,
performLayout,
layoutContext);
float containerCrossAxis = availableInnerCrossDim;
if (measureModeCrossDim == YGMeasureModeUndefined ||
measureModeCrossDim == YGMeasureModeAtMost) {
// Compute the cross axis from the max cross dimension of the children.
containerCrossAxis =
YGNodeBoundAxis(
node,
crossAxis,
collectedFlexItemsValues.crossDim + paddingAndBorderAxisCross,
crossAxisownerSize,
ownerWidth) -
paddingAndBorderAxisCross;
}
// If there's no flex wrap, the cross dimension is defined by the container.
if (!isNodeFlexWrap && measureModeCrossDim == YGMeasureModeExactly) {
collectedFlexItemsValues.crossDim = availableInnerCrossDim;
}
// Clamp to the min/max size specified on the container.
collectedFlexItemsValues.crossDim =
YGNodeBoundAxis(
node,
crossAxis,
collectedFlexItemsValues.crossDim + paddingAndBorderAxisCross,
crossAxisownerSize,
ownerWidth) -
paddingAndBorderAxisCross;
// STEP 7: CROSS-AXIS ALIGNMENT
// We can skip child alignment if we're just measuring the container.
if (performLayout) {
for (uint32_t i = startOfLineIndex; i < endOfLineIndex; i++) {
const YGNodeRef child = node->getChild(i);
if (child->getStyle().display() == YGDisplayNone) {
continue;
}
if (child->getStyle().positionType() == YGPositionTypeAbsolute) {
// If the child is absolutely positioned and has a
// top/left/bottom/right set, override all the previously computed
// positions to set it correctly.
const bool isChildLeadingPosDefined =
child->isLeadingPositionDefined(crossAxis);
if (isChildLeadingPosDefined) {
child->setLayoutPosition(
child->getLeadingPosition(crossAxis, availableInnerCrossDim)
.unwrap() +
node->getLeadingBorder(crossAxis) +
child->getLeadingMargin(crossAxis, availableInnerWidth)
.unwrap(),
pos[crossAxis]);
}
// If leading position is not defined or calculations result in Nan,
// default to border + margin
if (!isChildLeadingPosDefined ||
YGFloatIsUndefined(child->getLayout().position[pos[crossAxis]])) {
child->setLayoutPosition(
node->getLeadingBorder(crossAxis) +
child->getLeadingMargin(crossAxis, availableInnerWidth)
.unwrap(),
pos[crossAxis]);
}
} else {
float leadingCrossDim = leadingPaddingAndBorderCross;
// For a relative children, we're either using alignItems (owner) or
// alignSelf (child) in order to determine the position in the cross
// axis
const YGAlign alignItem = YGNodeAlignItem(node, child);
// If the child uses align stretch, we need to lay it out one more
// time, this time forcing the cross-axis size to be the computed
// cross size for the current line.
if (alignItem == YGAlignStretch &&
child->marginLeadingValue(crossAxis).unit != YGUnitAuto &&
child->marginTrailingValue(crossAxis).unit != YGUnitAuto) {
// If the child defines a definite size for its cross axis, there's
// no need to stretch.
if (!YGNodeIsStyleDimDefined(
child, crossAxis, availableInnerCrossDim)) {
float childMainSize =
child->getLayout().measuredDimensions[dim[mainAxis]];
const auto& childStyle = child->getStyle();
float childCrossSize = !childStyle.aspectRatio().isUndefined()
? child->getMarginForAxis(crossAxis, availableInnerWidth)
.unwrap() +
(isMainAxisRow
? childMainSize / childStyle.aspectRatio().unwrap()
: childMainSize * childStyle.aspectRatio().unwrap())
: collectedFlexItemsValues.crossDim;
childMainSize +=
child->getMarginForAxis(mainAxis, availableInnerWidth)
.unwrap();
YGMeasureMode childMainMeasureMode = YGMeasureModeExactly;
YGMeasureMode childCrossMeasureMode = YGMeasureModeExactly;
YGConstrainMaxSizeForMode(
child,
mainAxis,
availableInnerMainDim,
availableInnerWidth,
&childMainMeasureMode,
&childMainSize);
YGConstrainMaxSizeForMode(
child,
crossAxis,
availableInnerCrossDim,
availableInnerWidth,
&childCrossMeasureMode,
&childCrossSize);
const float childWidth =
isMainAxisRow ? childMainSize : childCrossSize;
const float childHeight =
!isMainAxisRow ? childMainSize : childCrossSize;
auto alignContent = node->getStyle().alignContent();
auto crossAxisDoesNotGrow =
alignContent != YGAlignStretch && isNodeFlexWrap;
const YGMeasureMode childWidthMeasureMode =
YGFloatIsUndefined(childWidth) ||
(!isMainAxisRow && crossAxisDoesNotGrow)
? YGMeasureModeUndefined
: YGMeasureModeExactly;
const YGMeasureMode childHeightMeasureMode =
YGFloatIsUndefined(childHeight) ||
(isMainAxisRow && crossAxisDoesNotGrow)
? YGMeasureModeUndefined
: YGMeasureModeExactly;
YGLayoutNodeInternal(
child,
childWidth,
childHeight,
direction,
childWidthMeasureMode,
childHeightMeasureMode,
availableInnerWidth,
availableInnerHeight,
true,
LayoutPassReason::kStretch,
config,
layoutMarkerData,
layoutContext,
depth,
generationCount);
}
} else {
const float remainingCrossDim = containerCrossAxis -
YGNodeDimWithMargin(child, crossAxis, availableInnerWidth);
if (child->marginLeadingValue(crossAxis).unit == YGUnitAuto &&
child->marginTrailingValue(crossAxis).unit == YGUnitAuto) {
leadingCrossDim += YGFloatMax(0.0f, remainingCrossDim / 2);
} else if (
child->marginTrailingValue(crossAxis).unit == YGUnitAuto) {
// No-Op
} else if (
child->marginLeadingValue(crossAxis).unit == YGUnitAuto) {
leadingCrossDim += YGFloatMax(0.0f, remainingCrossDim);
} else if (alignItem == YGAlignFlexStart) {
// No-Op
} else if (alignItem == YGAlignCenter) {
leadingCrossDim += remainingCrossDim / 2;
} else {
leadingCrossDim += remainingCrossDim;
}
}
// And we apply the position
child->setLayoutPosition(
child->getLayout().position[pos[crossAxis]] + totalLineCrossDim +
leadingCrossDim,
pos[crossAxis]);
}
}
}
totalLineCrossDim += collectedFlexItemsValues.crossDim;
maxLineMainDim =
YGFloatMax(maxLineMainDim, collectedFlexItemsValues.mainDim);
}
// STEP 8: MULTI-LINE CONTENT ALIGNMENT
// currentLead stores the size of the cross dim
if (performLayout && (isNodeFlexWrap || YGIsBaselineLayout(node))) {
float crossDimLead = 0;
float currentLead = leadingPaddingAndBorderCross;
if (!YGFloatIsUndefined(availableInnerCrossDim)) {
const float remainingAlignContentDim =
availableInnerCrossDim - totalLineCrossDim;
switch (node->getStyle().alignContent()) {
case YGAlignFlexEnd:
currentLead += remainingAlignContentDim;
break;
case YGAlignCenter:
currentLead += remainingAlignContentDim / 2;
break;
case YGAlignStretch:
if (availableInnerCrossDim > totalLineCrossDim) {
crossDimLead = remainingAlignContentDim / lineCount;
}
break;
case YGAlignSpaceAround:
if (availableInnerCrossDim > totalLineCrossDim) {
currentLead += remainingAlignContentDim / (2 * lineCount);
if (lineCount > 1) {
crossDimLead = remainingAlignContentDim / lineCount;
}
} else {
currentLead += remainingAlignContentDim / 2;
}
break;
case YGAlignSpaceBetween:
if (availableInnerCrossDim > totalLineCrossDim && lineCount > 1) {
crossDimLead = remainingAlignContentDim / (lineCount - 1);
}
break;
case YGAlignAuto:
case YGAlignFlexStart:
case YGAlignBaseline:
break;
}
}
uint32_t endIndex = 0;
for (uint32_t i = 0; i < lineCount; i++) {
const uint32_t startIndex = endIndex;
uint32_t ii;
// compute the line's height and find the endIndex
float lineHeight = 0;
float maxAscentForCurrentLine = 0;
float maxDescentForCurrentLine = 0;
for (ii = startIndex; ii < childCount; ii++) {
const YGNodeRef child = node->getChild(ii);
if (child->getStyle().display() == YGDisplayNone) {
continue;
}
if (child->getStyle().positionType() == YGPositionTypeRelative) {
if (child->getLineIndex() != i) {
break;
}
if (YGNodeIsLayoutDimDefined(child, crossAxis)) {
lineHeight = YGFloatMax(
lineHeight,
child->getLayout().measuredDimensions[dim[crossAxis]] +
child->getMarginForAxis(crossAxis, availableInnerWidth)
.unwrap());
}
if (YGNodeAlignItem(node, child) == YGAlignBaseline) {
const float ascent = YGBaseline(child, layoutContext) +
child
->getLeadingMargin(
YGFlexDirectionColumn, availableInnerWidth)
.unwrap();
const float descent =
child->getLayout().measuredDimensions[YGDimensionHeight] +
child
->getMarginForAxis(
YGFlexDirectionColumn, availableInnerWidth)
.unwrap() -
ascent;
maxAscentForCurrentLine =
YGFloatMax(maxAscentForCurrentLine, ascent);
maxDescentForCurrentLine =
YGFloatMax(maxDescentForCurrentLine, descent);
lineHeight = YGFloatMax(
lineHeight, maxAscentForCurrentLine + maxDescentForCurrentLine);
}
}
}
endIndex = ii;
lineHeight += crossDimLead;
if (performLayout) {
for (ii = startIndex; ii < endIndex; ii++) {
const YGNodeRef child = node->getChild(ii);
if (child->getStyle().display() == YGDisplayNone) {
continue;
}
if (child->getStyle().positionType() == YGPositionTypeRelative) {
switch (YGNodeAlignItem(node, child)) {
case YGAlignFlexStart: {
child->setLayoutPosition(
currentLead +
child->getLeadingMargin(crossAxis, availableInnerWidth)
.unwrap(),
pos[crossAxis]);
break;
}
case YGAlignFlexEnd: {
child->setLayoutPosition(
currentLead + lineHeight -
child->getTrailingMargin(crossAxis, availableInnerWidth)
.unwrap() -
child->getLayout().measuredDimensions[dim[crossAxis]],
pos[crossAxis]);
break;
}
case YGAlignCenter: {
float childHeight =
child->getLayout().measuredDimensions[dim[crossAxis]];
child->setLayoutPosition(
currentLead + (lineHeight - childHeight) / 2,
pos[crossAxis]);
break;
}
case YGAlignStretch: {
child->setLayoutPosition(
currentLead +
child->getLeadingMargin(crossAxis, availableInnerWidth)
.unwrap(),
pos[crossAxis]);
// Remeasure child with the line height as it as been only
// measured with the owners height yet.
if (!YGNodeIsStyleDimDefined(
child, crossAxis, availableInnerCrossDim)) {
const float childWidth = isMainAxisRow
? (child->getLayout()
.measuredDimensions[YGDimensionWidth] +
child->getMarginForAxis(mainAxis, availableInnerWidth)
.unwrap())
: lineHeight;
const float childHeight = !isMainAxisRow
? (child->getLayout()
.measuredDimensions[YGDimensionHeight] +
child->getMarginForAxis(crossAxis, availableInnerWidth)
.unwrap())
: lineHeight;
if (!(YGFloatsEqual(
childWidth,
child->getLayout()
.measuredDimensions[YGDimensionWidth]) &&
YGFloatsEqual(
childHeight,
child->getLayout()
.measuredDimensions[YGDimensionHeight]))) {
YGLayoutNodeInternal(
child,
childWidth,
childHeight,
direction,
YGMeasureModeExactly,
YGMeasureModeExactly,
availableInnerWidth,
availableInnerHeight,
true,
LayoutPassReason::kMultilineStretch,
config,
layoutMarkerData,
layoutContext,
depth,
generationCount);
}
}
break;
}
case YGAlignBaseline: {
child->setLayoutPosition(
currentLead + maxAscentForCurrentLine -
YGBaseline(child, layoutContext) +
child
->getLeadingPosition(
YGFlexDirectionColumn, availableInnerCrossDim)
.unwrap(),
YGEdgeTop);
break;
}
case YGAlignAuto:
case YGAlignSpaceBetween:
case YGAlignSpaceAround:
break;
}
}
}
}
currentLead += lineHeight;
}
}
// STEP 9: COMPUTING FINAL DIMENSIONS
node->setLayoutMeasuredDimension(
YGNodeBoundAxis(
node,
YGFlexDirectionRow,
availableWidth - marginAxisRow,
ownerWidth,
ownerWidth),
YGDimensionWidth);
node->setLayoutMeasuredDimension(
YGNodeBoundAxis(
node,
YGFlexDirectionColumn,
availableHeight - marginAxisColumn,
ownerHeight,
ownerWidth),
YGDimensionHeight);
// If the user didn't specify a width or height for the node, set the
// dimensions based on the children.
if (measureModeMainDim == YGMeasureModeUndefined ||
(node->getStyle().overflow() != YGOverflowScroll &&
measureModeMainDim == YGMeasureModeAtMost)) {
// Clamp the size to the min/max size, if specified, and make sure it
// doesn't go below the padding and border amount.
node->setLayoutMeasuredDimension(
YGNodeBoundAxis(
node, mainAxis, maxLineMainDim, mainAxisownerSize, ownerWidth),
dim[mainAxis]);
} else if (
measureModeMainDim == YGMeasureModeAtMost &&
node->getStyle().overflow() == YGOverflowScroll) {
node->setLayoutMeasuredDimension(
YGFloatMax(
YGFloatMin(
availableInnerMainDim + paddingAndBorderAxisMain,
YGNodeBoundAxisWithinMinAndMax(
node,
mainAxis,
YGFloatOptional{maxLineMainDim},
mainAxisownerSize)
.unwrap()),
paddingAndBorderAxisMain),
dim[mainAxis]);
}
if (measureModeCrossDim == YGMeasureModeUndefined ||
(node->getStyle().overflow() != YGOverflowScroll &&
measureModeCrossDim == YGMeasureModeAtMost)) {
// Clamp the size to the min/max size, if specified, and make sure it
// doesn't go below the padding and border amount.
node->setLayoutMeasuredDimension(
YGNodeBoundAxis(
node,
crossAxis,
totalLineCrossDim + paddingAndBorderAxisCross,
crossAxisownerSize,
ownerWidth),
dim[crossAxis]);
} else if (
measureModeCrossDim == YGMeasureModeAtMost &&
node->getStyle().overflow() == YGOverflowScroll) {
node->setLayoutMeasuredDimension(
YGFloatMax(
YGFloatMin(
availableInnerCrossDim + paddingAndBorderAxisCross,
YGNodeBoundAxisWithinMinAndMax(
node,
crossAxis,
YGFloatOptional{totalLineCrossDim +
paddingAndBorderAxisCross},
crossAxisownerSize)
.unwrap()),
paddingAndBorderAxisCross),
dim[crossAxis]);
}
// As we only wrapped in normal direction yet, we need to reverse the
// positions on wrap-reverse.
if (performLayout && node->getStyle().flexWrap() == YGWrapWrapReverse) {
for (uint32_t i = 0; i < childCount; i++) {
const YGNodeRef child = YGNodeGetChild(node, i);
if (child->getStyle().positionType() == YGPositionTypeRelative) {
child->setLayoutPosition(
node->getLayout().measuredDimensions[dim[crossAxis]] -
child->getLayout().position[pos[crossAxis]] -
child->getLayout().measuredDimensions[dim[crossAxis]],
pos[crossAxis]);
}
}
}
if (performLayout) {
// STEP 10: SIZING AND POSITIONING ABSOLUTE CHILDREN
for (auto child : node->getChildren()) {
if (child->getStyle().positionType() != YGPositionTypeAbsolute) {
continue;
}
YGNodeAbsoluteLayoutChild(
node,
child,
availableInnerWidth,
isMainAxisRow ? measureModeMainDim : measureModeCrossDim,
availableInnerHeight,
direction,
config,
layoutMarkerData,
layoutContext,
depth,
generationCount);
}
// STEP 11: SETTING TRAILING POSITIONS FOR CHILDREN
const bool needsMainTrailingPos = mainAxis == YGFlexDirectionRowReverse ||
mainAxis == YGFlexDirectionColumnReverse;
const bool needsCrossTrailingPos = crossAxis == YGFlexDirectionRowReverse ||
crossAxis == YGFlexDirectionColumnReverse;
// Set trailing position if necessary.
if (needsMainTrailingPos || needsCrossTrailingPos) {
for (uint32_t i = 0; i < childCount; i++) {
const YGNodeRef child = node->getChild(i);
if (child->getStyle().display() == YGDisplayNone) {
continue;
}
if (needsMainTrailingPos) {
YGNodeSetChildTrailingPosition(node, child, mainAxis);
}
if (needsCrossTrailingPos) {
YGNodeSetChildTrailingPosition(node, child, crossAxis);
}
}
}
}
}
bool gPrintChanges = false;
bool gPrintSkips = false;
static const char* spacer =
" ";
static const char* YGSpacer(const unsigned long level) {
const size_t spacerLen = strlen(spacer);
if (level > spacerLen) {
return &spacer[0];
} else {
return &spacer[spacerLen - level];
}
}
static const char* YGMeasureModeName(
const YGMeasureMode mode,
const bool performLayout) {
constexpr auto N = enums::count<YGMeasureMode>();
const char* kMeasureModeNames[N] = {"UNDEFINED", "EXACTLY", "AT_MOST"};
const char* kLayoutModeNames[N] = {
"LAY_UNDEFINED", "LAY_EXACTLY", "LAY_AT_MOST"};
if (mode >= N) {
return "";
}
return performLayout ? kLayoutModeNames[mode] : kMeasureModeNames[mode];
}
static inline bool YGMeasureModeSizeIsExactAndMatchesOldMeasuredSize(
YGMeasureMode sizeMode,
float size,
float lastComputedSize) {
return sizeMode == YGMeasureModeExactly &&
YGFloatsEqual(size, lastComputedSize);
}
static inline bool YGMeasureModeOldSizeIsUnspecifiedAndStillFits(
YGMeasureMode sizeMode,
float size,
YGMeasureMode lastSizeMode,
float lastComputedSize) {
return sizeMode == YGMeasureModeAtMost &&
lastSizeMode == YGMeasureModeUndefined &&
(size >= lastComputedSize || YGFloatsEqual(size, lastComputedSize));
}
static inline bool YGMeasureModeNewMeasureSizeIsStricterAndStillValid(
YGMeasureMode sizeMode,
float size,
YGMeasureMode lastSizeMode,
float lastSize,
float lastComputedSize) {
return lastSizeMode == YGMeasureModeAtMost &&
sizeMode == YGMeasureModeAtMost && !YGFloatIsUndefined(lastSize) &&
!YGFloatIsUndefined(size) && !YGFloatIsUndefined(lastComputedSize) &&
lastSize > size &&
(lastComputedSize <= size || YGFloatsEqual(size, lastComputedSize));
}
float YGRoundValueToPixelGrid(
const float value,
const float pointScaleFactor,
const bool forceCeil,
const bool forceFloor) {
float scaledValue = value * pointScaleFactor;
// We want to calculate `fractial` such that `floor(scaledValue) = scaledValue
// - fractial`.
float fractial = fmodf(scaledValue, 1.0f);
if (fractial < 0) {
// This branch is for handling negative numbers for `value`.
//
// Regarding `floor` and `ceil`. Note that for a number x, `floor(x) <= x <=
// ceil(x)` even for negative numbers. Here are a couple of examples:
// - x = 2.2: floor( 2.2) = 2, ceil( 2.2) = 3
// - x = -2.2: floor(-2.2) = -3, ceil(-2.2) = -2
//
// Regarding `fmodf`. For fractional negative numbers, `fmodf` returns a
// negative number. For example, `fmodf(-2.2) = -0.2`. However, we want
// `fractial` to be the number such that subtracting it from `value` will
// give us `floor(value)`. In the case of negative numbers, adding 1 to
// `fmodf(value)` gives us this. Let's continue the example from above:
// - fractial = fmodf(-2.2) = -0.2
// - Add 1 to the fraction: fractial2 = fractial + 1 = -0.2 + 1 = 0.8
// - Finding the `floor`: -2.2 - fractial2 = -2.2 - 0.8 = -3
++fractial;
}
if (YGFloatsEqual(fractial, 0)) {
// First we check if the value is already rounded
scaledValue = scaledValue - fractial;
} else if (YGFloatsEqual(fractial, 1.0f)) {
scaledValue = scaledValue - fractial + 1.0f;
} else if (forceCeil) {
// Next we check if we need to use forced rounding
scaledValue = scaledValue - fractial + 1.0f;
} else if (forceFloor) {
scaledValue = scaledValue - fractial;
} else {
// Finally we just round the value
scaledValue = scaledValue - fractial +
(!YGFloatIsUndefined(fractial) &&
(fractial > 0.5f || YGFloatsEqual(fractial, 0.5f))
? 1.0f
: 0.0f);
}
return (YGFloatIsUndefined(scaledValue) ||
YGFloatIsUndefined(pointScaleFactor))
? YGUndefined
: scaledValue / pointScaleFactor;
}
bool YGNodeCanUseCachedMeasurement(
const YGMeasureMode widthMode,
const float width,
const YGMeasureMode heightMode,
const float height,
const YGMeasureMode lastWidthMode,
const float lastWidth,
const YGMeasureMode lastHeightMode,
const float lastHeight,
const float lastComputedWidth,
const float lastComputedHeight,
const float marginRow,
const float marginColumn,
const YGConfigRef config) {
if ((!YGFloatIsUndefined(lastComputedHeight) && lastComputedHeight < 0) ||
(!YGFloatIsUndefined(lastComputedWidth) && lastComputedWidth < 0)) {
return false;
}
bool useRoundedComparison =
config != nullptr && config->pointScaleFactor != 0;
const float effectiveWidth = useRoundedComparison
? YGRoundValueToPixelGrid(width, config->pointScaleFactor, false, false)
: width;
const float effectiveHeight = useRoundedComparison
? YGRoundValueToPixelGrid(height, config->pointScaleFactor, false, false)
: height;
const float effectiveLastWidth = useRoundedComparison
? YGRoundValueToPixelGrid(
lastWidth, config->pointScaleFactor, false, false)
: lastWidth;
const float effectiveLastHeight = useRoundedComparison
? YGRoundValueToPixelGrid(
lastHeight, config->pointScaleFactor, false, false)
: lastHeight;
const bool hasSameWidthSpec = lastWidthMode == widthMode &&
YGFloatsEqual(effectiveLastWidth, effectiveWidth);
const bool hasSameHeightSpec = lastHeightMode == heightMode &&
YGFloatsEqual(effectiveLastHeight, effectiveHeight);
const bool widthIsCompatible =
hasSameWidthSpec ||
YGMeasureModeSizeIsExactAndMatchesOldMeasuredSize(
widthMode, width - marginRow, lastComputedWidth) ||
YGMeasureModeOldSizeIsUnspecifiedAndStillFits(
widthMode, width - marginRow, lastWidthMode, lastComputedWidth) ||
YGMeasureModeNewMeasureSizeIsStricterAndStillValid(
widthMode,
width - marginRow,
lastWidthMode,
lastWidth,
lastComputedWidth);
const bool heightIsCompatible =
hasSameHeightSpec ||
YGMeasureModeSizeIsExactAndMatchesOldMeasuredSize(
heightMode, height - marginColumn, lastComputedHeight) ||
YGMeasureModeOldSizeIsUnspecifiedAndStillFits(
heightMode,
height - marginColumn,
lastHeightMode,
lastComputedHeight) ||
YGMeasureModeNewMeasureSizeIsStricterAndStillValid(
heightMode,
height - marginColumn,
lastHeightMode,
lastHeight,
lastComputedHeight);
return widthIsCompatible && heightIsCompatible;
}
//
// This is a wrapper around the YGNodelayoutImpl function. It determines whether
// the layout request is redundant and can be skipped.
//
// Parameters:
// Input parameters are the same as YGNodelayoutImpl (see above)
// Return parameter is true if layout was performed, false if skipped
//
bool YGLayoutNodeInternal(
const YGNodeRef node,
const float availableWidth,
const float availableHeight,
const YGDirection ownerDirection,
const YGMeasureMode widthMeasureMode,
const YGMeasureMode heightMeasureMode,
const float ownerWidth,
const float ownerHeight,
const bool performLayout,
const LayoutPassReason reason,
const YGConfigRef config,
LayoutData& layoutMarkerData,
void* const layoutContext,
uint32_t depth,
const uint32_t generationCount) {
YGLayout* layout = &node->getLayout();
depth++;
const bool needToVisitNode =
(node->isDirty() && layout->generationCount != generationCount) ||
layout->lastOwnerDirection != ownerDirection;
if (needToVisitNode) {
// Invalidate the cached results.
layout->nextCachedMeasurementsIndex = 0;
layout->cachedLayout.widthMeasureMode = (YGMeasureMode) -1;
layout->cachedLayout.heightMeasureMode = (YGMeasureMode) -1;
layout->cachedLayout.computedWidth = -1;
layout->cachedLayout.computedHeight = -1;
}
YGCachedMeasurement* cachedResults = nullptr;
// Determine whether the results are already cached. We maintain a separate
// cache for layouts and measurements. A layout operation modifies the
// positions and dimensions for nodes in the subtree. The algorithm assumes
// that each node gets layed out a maximum of one time per tree layout, but
// multiple measurements may be required to resolve all of the flex
// dimensions. We handle nodes with measure functions specially here because
// they are the most expensive to measure, so it's worth avoiding redundant
// measurements if at all possible.
if (node->hasMeasureFunc()) {
const float marginAxisRow =
node->getMarginForAxis(YGFlexDirectionRow, ownerWidth).unwrap();
const float marginAxisColumn =
node->getMarginForAxis(YGFlexDirectionColumn, ownerWidth).unwrap();
// First, try to use the layout cache.
if (YGNodeCanUseCachedMeasurement(
widthMeasureMode,
availableWidth,
heightMeasureMode,
availableHeight,
layout->cachedLayout.widthMeasureMode,
layout->cachedLayout.availableWidth,
layout->cachedLayout.heightMeasureMode,
layout->cachedLayout.availableHeight,
layout->cachedLayout.computedWidth,
layout->cachedLayout.computedHeight,
marginAxisRow,
marginAxisColumn,
config)) {
cachedResults = &layout->cachedLayout;
} else {
// Try to use the measurement cache.
for (uint32_t i = 0; i < layout->nextCachedMeasurementsIndex; i++) {
if (YGNodeCanUseCachedMeasurement(
widthMeasureMode,
availableWidth,
heightMeasureMode,
availableHeight,
layout->cachedMeasurements[i].widthMeasureMode,
layout->cachedMeasurements[i].availableWidth,
layout->cachedMeasurements[i].heightMeasureMode,
layout->cachedMeasurements[i].availableHeight,
layout->cachedMeasurements[i].computedWidth,
layout->cachedMeasurements[i].computedHeight,
marginAxisRow,
marginAxisColumn,
config)) {
cachedResults = &layout->cachedMeasurements[i];
break;
}
}
}
} else if (performLayout) {
if (YGFloatsEqual(layout->cachedLayout.availableWidth, availableWidth) &&
YGFloatsEqual(layout->cachedLayout.availableHeight, availableHeight) &&
layout->cachedLayout.widthMeasureMode == widthMeasureMode &&
layout->cachedLayout.heightMeasureMode == heightMeasureMode) {
cachedResults = &layout->cachedLayout;
}
} else {
for (uint32_t i = 0; i < layout->nextCachedMeasurementsIndex; i++) {
if (YGFloatsEqual(
layout->cachedMeasurements[i].availableWidth, availableWidth) &&
YGFloatsEqual(
layout->cachedMeasurements[i].availableHeight, availableHeight) &&
layout->cachedMeasurements[i].widthMeasureMode == widthMeasureMode &&
layout->cachedMeasurements[i].heightMeasureMode ==
heightMeasureMode) {
cachedResults = &layout->cachedMeasurements[i];
break;
}
}
}
if (!needToVisitNode && cachedResults != nullptr) {
layout->measuredDimensions[YGDimensionWidth] = cachedResults->computedWidth;
layout->measuredDimensions[YGDimensionHeight] =
cachedResults->computedHeight;
(performLayout ? layoutMarkerData.cachedLayouts
: layoutMarkerData.cachedMeasures) += 1;
if (gPrintChanges && gPrintSkips) {
Log::log(
node,
YGLogLevelVerbose,
nullptr,
"%s%d.{[skipped] ",
YGSpacer(depth),
depth);
node->print(layoutContext);
Log::log(
node,
YGLogLevelVerbose,
nullptr,
"wm: %s, hm: %s, aw: %f ah: %f => d: (%f, %f) %s\n",
YGMeasureModeName(widthMeasureMode, performLayout),
YGMeasureModeName(heightMeasureMode, performLayout),
availableWidth,
availableHeight,
cachedResults->computedWidth,
cachedResults->computedHeight,
LayoutPassReasonToString(reason));
}
} else {
if (gPrintChanges) {
Log::log(
node,
YGLogLevelVerbose,
nullptr,
"%s%d.{%s",
YGSpacer(depth),
depth,
needToVisitNode ? "*" : "");
node->print(layoutContext);
Log::log(
node,
YGLogLevelVerbose,
nullptr,
"wm: %s, hm: %s, aw: %f ah: %f %s\n",
YGMeasureModeName(widthMeasureMode, performLayout),
YGMeasureModeName(heightMeasureMode, performLayout),
availableWidth,
availableHeight,
LayoutPassReasonToString(reason));
}
YGNodelayoutImpl(
node,
availableWidth,
availableHeight,
ownerDirection,
widthMeasureMode,
heightMeasureMode,
ownerWidth,
ownerHeight,
performLayout,
config,
layoutMarkerData,
layoutContext,
depth,
generationCount,
reason);
if (gPrintChanges) {
Log::log(
node,
YGLogLevelVerbose,
nullptr,
"%s%d.}%s",
YGSpacer(depth),
depth,
needToVisitNode ? "*" : "");
node->print(layoutContext);
Log::log(
node,
YGLogLevelVerbose,
nullptr,
"wm: %s, hm: %s, d: (%f, %f) %s\n",
YGMeasureModeName(widthMeasureMode, performLayout),
YGMeasureModeName(heightMeasureMode, performLayout),
layout->measuredDimensions[YGDimensionWidth],
layout->measuredDimensions[YGDimensionHeight],
LayoutPassReasonToString(reason));
}
layout->lastOwnerDirection = ownerDirection;
if (cachedResults == nullptr) {
if (layout->nextCachedMeasurementsIndex + 1 >
(uint32_t) layoutMarkerData.maxMeasureCache) {
layoutMarkerData.maxMeasureCache =
layout->nextCachedMeasurementsIndex + 1;
}
if (layout->nextCachedMeasurementsIndex == YG_MAX_CACHED_RESULT_COUNT) {
if (gPrintChanges) {
Log::log(node, YGLogLevelVerbose, nullptr, "Out of cache entries!\n");
}
layout->nextCachedMeasurementsIndex = 0;
}
YGCachedMeasurement* newCacheEntry;
if (performLayout) {
// Use the single layout cache entry.
newCacheEntry = &layout->cachedLayout;
} else {
// Allocate a new measurement cache entry.
newCacheEntry =
&layout->cachedMeasurements[layout->nextCachedMeasurementsIndex];
layout->nextCachedMeasurementsIndex++;
}
newCacheEntry->availableWidth = availableWidth;
newCacheEntry->availableHeight = availableHeight;
newCacheEntry->widthMeasureMode = widthMeasureMode;
newCacheEntry->heightMeasureMode = heightMeasureMode;
newCacheEntry->computedWidth =
layout->measuredDimensions[YGDimensionWidth];
newCacheEntry->computedHeight =
layout->measuredDimensions[YGDimensionHeight];
}
}
if (performLayout) {
node->setLayoutDimension(
node->getLayout().measuredDimensions[YGDimensionWidth],
YGDimensionWidth);
node->setLayoutDimension(
node->getLayout().measuredDimensions[YGDimensionHeight],
YGDimensionHeight);
node->setHasNewLayout(true);
node->setDirty(false);
}
layout->generationCount = generationCount;
LayoutType layoutType;
if (performLayout) {
layoutType = !needToVisitNode && cachedResults == &layout->cachedLayout
? LayoutType::kCachedLayout
: LayoutType::kLayout;
} else {
layoutType = cachedResults != nullptr ? LayoutType::kCachedMeasure
: LayoutType::kMeasure;
}
Event::publish<Event::NodeLayout>(node, {layoutType, layoutContext});
return (needToVisitNode || cachedResults == nullptr);
}
void YGConfigSetPointScaleFactor(
const YGConfigRef config,
const float pixelsInPoint) {
YGAssertWithConfig(
config,
pixelsInPoint >= 0.0f,
"Scale f