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fragment.rs
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fragment.rs
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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
//! The `Fragment` type, which represents the leaves of the layout tree.
#![deny(unsafe_code)]
use app_units::Au;
use canvas_traits::CanvasMsg;
use context::{LayoutContext, with_thread_local_font_context};
use euclid::{Matrix4D, Point2D, Radians, Rect, Size2D};
use floats::ClearType;
use flow::{self, ImmutableFlowUtils};
use flow_ref::FlowRef;
use gfx;
use gfx::display_list::{BLUR_INFLATION_FACTOR, OpaqueNode};
use gfx::text::glyph::ByteIndex;
use gfx::text::text_run::{TextRun, TextRunSlice};
use gfx_traits::{FragmentType, StackingContextId};
use inline::{FIRST_FRAGMENT_OF_ELEMENT, InlineFragmentContext, InlineFragmentNodeInfo};
use inline::{InlineMetrics, LAST_FRAGMENT_OF_ELEMENT, LineMetrics};
use ipc_channel::ipc::IpcSender;
#[cfg(debug_assertions)]
use layout_debug;
use model::{self, IntrinsicISizes, IntrinsicISizesContribution, MaybeAuto, SizeConstraint};
use model::{style_length, ToGfxMatrix};
use msg::constellation_msg::PipelineId;
use net_traits::image::base::{Image, ImageMetadata};
use net_traits::image_cache::{ImageOrMetadataAvailable, UsePlaceholder};
use range::*;
use script_layout_interface::HTMLCanvasData;
use script_layout_interface::SVGSVGData;
use script_layout_interface::wrapper_traits::{PseudoElementType, ThreadSafeLayoutElement, ThreadSafeLayoutNode};
use serde::ser::{Serialize, SerializeStruct, Serializer};
use servo_url::ServoUrl;
use std::{f32, fmt};
use std::borrow::ToOwned;
use std::cmp::{Ordering, max, min};
use std::collections::LinkedList;
use std::sync::{Arc, Mutex};
use style::arc_ptr_eq;
use style::computed_values::{border_collapse, box_sizing, clear, color, display, mix_blend_mode};
use style::computed_values::{overflow_wrap, overflow_x, position, text_decoration_line, transform};
use style::computed_values::{transform_style, vertical_align, white_space, word_break};
use style::computed_values::content::ContentItem;
use style::logical_geometry::{Direction, LogicalMargin, LogicalRect, LogicalSize, WritingMode};
use style::properties::ServoComputedValues;
use style::selector_parser::RestyleDamage;
use style::servo::restyle_damage::RECONSTRUCT_FLOW;
use style::str::char_is_whitespace;
use style::values::{self, Either, Auto};
use style::values::computed::{LengthOrPercentage, LengthOrPercentageOrAuto};
use text;
use text::TextRunScanner;
use wrapper::ThreadSafeLayoutNodeHelpers;
// From gfxFontConstants.h in Firefox.
static FONT_SUBSCRIPT_OFFSET_RATIO: f32 = 0.20;
static FONT_SUPERSCRIPT_OFFSET_RATIO: f32 = 0.34;
// https://drafts.csswg.org/css-images/#default-object-size
static DEFAULT_REPLACED_WIDTH: i32 = 300;
static DEFAULT_REPLACED_HEIGHT: i32 = 150;
/// Fragments (`struct Fragment`) are the leaves of the layout tree. They cannot position
/// themselves. In general, fragments do not have a simple correspondence with CSS fragments in the
/// specification:
///
/// * Several fragments may correspond to the same CSS box or DOM node. For example, a CSS text box
/// broken across two lines is represented by two fragments.
///
/// * Some CSS fragments are not created at all, such as some anonymous block fragments induced by
/// inline fragments with block-level sibling fragments. In that case, Servo uses an `InlineFlow`
/// with `BlockFlow` siblings; the `InlineFlow` is block-level, but not a block container. It is
/// positioned as if it were a block fragment, but its children are positioned according to
/// inline flow.
///
/// A `SpecificFragmentInfo::Generic` is an empty fragment that contributes only borders, margins,
/// padding, and backgrounds. It is analogous to a CSS nonreplaced content box.
///
/// A fragment's type influences how its styles are interpreted during layout. For example,
/// replaced content such as images are resized differently from tables, text, or other content.
/// Different types of fragments may also contain custom data; for example, text fragments contain
/// text.
///
/// Do not add fields to this structure unless they're really really mega necessary! Fragments get
/// moved around a lot and thus their size impacts performance of layout quite a bit.
///
/// FIXME(#2260, pcwalton): This can be slimmed down some by (at least) moving `inline_context`
/// to be on `InlineFlow` only.
#[derive(Clone)]
pub struct Fragment {
/// An opaque reference to the DOM node that this `Fragment` originates from.
pub node: OpaqueNode,
/// The CSS style of this fragment.
pub style: Arc<ServoComputedValues>,
/// The CSS style of this fragment when it's selected
pub selected_style: Arc<ServoComputedValues>,
/// The position of this fragment relative to its owning flow. The size includes padding and
/// border, but not margin.
///
/// NB: This does not account for relative positioning.
/// NB: Collapsed borders are not included in this.
pub border_box: LogicalRect<Au>,
/// The sum of border and padding; i.e. the distance from the edge of the border box to the
/// content edge of the fragment.
pub border_padding: LogicalMargin<Au>,
/// The margin of the content box.
pub margin: LogicalMargin<Au>,
/// Info specific to the kind of fragment. Keep this enum small.
pub specific: SpecificFragmentInfo,
/// Holds the style context information for fragments that are part of an inline formatting
/// context.
pub inline_context: Option<InlineFragmentContext>,
/// How damaged this fragment is since last reflow.
pub restyle_damage: RestyleDamage,
/// The pseudo-element that this fragment represents.
pub pseudo: PseudoElementType<()>,
/// Various flags for this fragment.
pub flags: FragmentFlags,
/// A debug ID that is consistent for the life of this fragment (via transform etc).
/// This ID should not be considered stable across multiple layouts or fragment
/// manipulations.
debug_id: DebugId,
/// The ID of the StackingContext that contains this fragment. This is initialized
/// to 0, but it assigned during the collect_stacking_contexts phase of display
/// list construction.
pub stacking_context_id: StackingContextId,
}
impl Serialize for Fragment {
fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
let mut serializer = try!(serializer.serialize_struct("fragment", 3));
try!(serializer.serialize_field("id", &self.debug_id));
try!(serializer.serialize_field("border_box", &self.border_box));
try!(serializer.serialize_field("margin", &self.margin));
serializer.end()
}
}
/// Info specific to the kind of fragment.
///
/// Keep this enum small. As in, no more than one word. Or pcwalton will yell at you.
#[derive(Clone)]
pub enum SpecificFragmentInfo {
Generic,
/// A piece of generated content that cannot be resolved into `ScannedText` until the generated
/// content resolution phase (e.g. an ordered list item marker).
GeneratedContent(Box<GeneratedContentInfo>),
Iframe(IframeFragmentInfo),
Image(Box<ImageFragmentInfo>),
Canvas(Box<CanvasFragmentInfo>),
Svg(Box<SvgFragmentInfo>),
/// A hypothetical box (see CSS 2.1 § 10.3.7) for an absolutely-positioned block that was
/// declared with `display: inline;`.
InlineAbsoluteHypothetical(InlineAbsoluteHypotheticalFragmentInfo),
InlineBlock(InlineBlockFragmentInfo),
/// An inline fragment that establishes an absolute containing block for its descendants (i.e.
/// a positioned inline fragment).
InlineAbsolute(InlineAbsoluteFragmentInfo),
ScannedText(Box<ScannedTextFragmentInfo>),
Table,
TableCell,
TableColumn(TableColumnFragmentInfo),
TableRow,
TableWrapper,
Multicol,
MulticolColumn,
UnscannedText(Box<UnscannedTextFragmentInfo>),
/// A container for a fragment that got truncated by text-overflow.
/// "Totally truncated fragments" are not rendered at all.
/// Text fragments may be partially truncated (in which case this renders like a text fragment).
/// Other fragments can only be totally truncated or not truncated at all.
TruncatedFragment(Box<TruncatedFragmentInfo>),
}
impl SpecificFragmentInfo {
fn restyle_damage(&self) -> RestyleDamage {
let flow =
match *self {
SpecificFragmentInfo::Canvas(_) |
SpecificFragmentInfo::GeneratedContent(_) |
SpecificFragmentInfo::Iframe(_) |
SpecificFragmentInfo::Image(_) |
SpecificFragmentInfo::ScannedText(_) |
SpecificFragmentInfo::Svg(_) |
SpecificFragmentInfo::Table |
SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableColumn(_) |
SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::TableWrapper |
SpecificFragmentInfo::Multicol |
SpecificFragmentInfo::MulticolColumn |
SpecificFragmentInfo::UnscannedText(_) |
SpecificFragmentInfo::TruncatedFragment(_) |
SpecificFragmentInfo::Generic => return RestyleDamage::empty(),
SpecificFragmentInfo::InlineAbsoluteHypothetical(ref info) => &info.flow_ref,
SpecificFragmentInfo::InlineAbsolute(ref info) => &info.flow_ref,
SpecificFragmentInfo::InlineBlock(ref info) => &info.flow_ref,
};
flow::base(&**flow).restyle_damage
}
pub fn get_type(&self) -> &'static str {
match *self {
SpecificFragmentInfo::Canvas(_) => "SpecificFragmentInfo::Canvas",
SpecificFragmentInfo::Generic => "SpecificFragmentInfo::Generic",
SpecificFragmentInfo::GeneratedContent(_) => "SpecificFragmentInfo::GeneratedContent",
SpecificFragmentInfo::Iframe(_) => "SpecificFragmentInfo::Iframe",
SpecificFragmentInfo::Image(_) => "SpecificFragmentInfo::Image",
SpecificFragmentInfo::InlineAbsolute(_) => "SpecificFragmentInfo::InlineAbsolute",
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) => {
"SpecificFragmentInfo::InlineAbsoluteHypothetical"
}
SpecificFragmentInfo::InlineBlock(_) => "SpecificFragmentInfo::InlineBlock",
SpecificFragmentInfo::ScannedText(_) => "SpecificFragmentInfo::ScannedText",
SpecificFragmentInfo::Svg(_) => "SpecificFragmentInfo::Svg",
SpecificFragmentInfo::Table => "SpecificFragmentInfo::Table",
SpecificFragmentInfo::TableCell => "SpecificFragmentInfo::TableCell",
SpecificFragmentInfo::TableColumn(_) => "SpecificFragmentInfo::TableColumn",
SpecificFragmentInfo::TableRow => "SpecificFragmentInfo::TableRow",
SpecificFragmentInfo::TableWrapper => "SpecificFragmentInfo::TableWrapper",
SpecificFragmentInfo::Multicol => "SpecificFragmentInfo::Multicol",
SpecificFragmentInfo::MulticolColumn => "SpecificFragmentInfo::MulticolColumn",
SpecificFragmentInfo::UnscannedText(_) => "SpecificFragmentInfo::UnscannedText",
SpecificFragmentInfo::TruncatedFragment(_) => "SpecificFragmentInfo::TruncatedFragment"
}
}
}
impl fmt::Debug for SpecificFragmentInfo {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
SpecificFragmentInfo::ScannedText(ref info) => write!(f, "{:?}", info.text()),
SpecificFragmentInfo::UnscannedText(ref info) => write!(f, "{:?}", info.text),
_ => Ok(())
}
}
}
/// Information for generated content.
#[derive(Clone)]
pub enum GeneratedContentInfo {
ListItem,
ContentItem(ContentItem),
/// Placeholder for elements with generated content that did not generate any fragments.
Empty,
}
/// A hypothetical box (see CSS 2.1 § 10.3.7) for an absolutely-positioned block that was declared
/// with `display: inline;`.
///
/// FIXME(pcwalton): Stop leaking this `FlowRef` to layout; that is not memory safe because layout
/// can clone it.
#[derive(Clone)]
pub struct InlineAbsoluteHypotheticalFragmentInfo {
pub flow_ref: FlowRef,
}
impl InlineAbsoluteHypotheticalFragmentInfo {
pub fn new(flow_ref: FlowRef) -> InlineAbsoluteHypotheticalFragmentInfo {
InlineAbsoluteHypotheticalFragmentInfo {
flow_ref: flow_ref,
}
}
}
/// A fragment that represents an inline-block element.
///
/// FIXME(pcwalton): Stop leaking this `FlowRef` to layout; that is not memory safe because layout
/// can clone it.
#[derive(Clone)]
pub struct InlineBlockFragmentInfo {
pub flow_ref: FlowRef,
}
impl InlineBlockFragmentInfo {
pub fn new(flow_ref: FlowRef) -> InlineBlockFragmentInfo {
InlineBlockFragmentInfo {
flow_ref: flow_ref,
}
}
}
/// An inline fragment that establishes an absolute containing block for its descendants (i.e.
/// a positioned inline fragment).
///
/// FIXME(pcwalton): Stop leaking this `FlowRef` to layout; that is not memory safe because layout
/// can clone it.
#[derive(Clone)]
pub struct InlineAbsoluteFragmentInfo {
pub flow_ref: FlowRef,
}
impl InlineAbsoluteFragmentInfo {
pub fn new(flow_ref: FlowRef) -> InlineAbsoluteFragmentInfo {
InlineAbsoluteFragmentInfo {
flow_ref: flow_ref,
}
}
}
#[derive(Clone)]
pub struct CanvasFragmentInfo {
pub ipc_renderer: Option<Arc<Mutex<IpcSender<CanvasMsg>>>>,
pub dom_width: Au,
pub dom_height: Au,
}
impl CanvasFragmentInfo {
pub fn new(data: HTMLCanvasData) -> CanvasFragmentInfo {
CanvasFragmentInfo {
ipc_renderer: data.ipc_renderer
.map(|renderer| Arc::new(Mutex::new(renderer))),
dom_width: Au::from_px(data.width as i32),
dom_height: Au::from_px(data.height as i32),
}
}
}
#[derive(Clone)]
pub struct SvgFragmentInfo {
pub dom_width: Au,
pub dom_height: Au,
}
impl SvgFragmentInfo {
pub fn new(data: SVGSVGData) -> SvgFragmentInfo {
SvgFragmentInfo {
dom_width: Au::from_px(data.width as i32),
dom_height: Au::from_px(data.height as i32),
}
}
}
/// A fragment that represents a replaced content image and its accompanying borders, shadows, etc.
#[derive(Clone)]
pub struct ImageFragmentInfo {
pub image: Option<Arc<Image>>,
pub metadata: Option<ImageMetadata>,
}
impl ImageFragmentInfo {
/// Creates a new image fragment from the given URL and local image cache.
///
/// FIXME(pcwalton): The fact that image fragments store the cache in the fragment makes little
/// sense to me.
pub fn new<N: ThreadSafeLayoutNode>(url: Option<ServoUrl>,
node: &N,
layout_context: &LayoutContext)
-> ImageFragmentInfo {
let image_or_metadata = url.and_then(|url| {
layout_context.get_or_request_image_or_meta(node.opaque(),
url,
UsePlaceholder::Yes)
});
let (image, metadata) = match image_or_metadata {
Some(ImageOrMetadataAvailable::ImageAvailable(i)) => {
(Some(i.clone()), Some(ImageMetadata { height: i.height, width: i.width } ))
}
Some(ImageOrMetadataAvailable::MetadataAvailable(m)) => {
(None, Some(m))
}
None => {
(None, None)
}
};
ImageFragmentInfo {
image: image,
metadata: metadata,
}
}
pub fn tile_image_round(position: &mut Au,
size: &mut Au,
absolute_anchor_origin: Au,
image_size: &mut Au) {
if *size == Au(0) || *image_size == Au(0) {
*position = Au(0);
*size =Au(0);
return;
}
let number_of_tiles = (size.to_f32_px() / image_size.to_f32_px()).round().max(1.0);
*image_size = *size / (number_of_tiles as i32);
ImageFragmentInfo::tile_image(position, size, absolute_anchor_origin, *image_size);
}
pub fn tile_image_spaced(position: &mut Au,
size: &mut Au,
tile_spacing: &mut Au,
absolute_anchor_origin: Au,
image_size: Au) {
if *size == Au(0) || image_size == Au(0) {
*position = Au(0);
*size = Au(0);
*tile_spacing = Au(0);
return;
}
// Per the spec, if the space available is not enough for two images, just tile as
// normal but only display a single tile.
if image_size * 2 >= *size {
ImageFragmentInfo::tile_image(position,
size,
absolute_anchor_origin,
image_size);
*tile_spacing = Au(0);
*size = image_size;
return;
}
// Take the box size, remove room for two tiles on the edges, and then calculate how many
// other tiles fit in between them.
let size_remaining = *size - (image_size * 2);
let num_middle_tiles = (size_remaining.to_f32_px() / image_size.to_f32_px()).floor() as i32;
// Allocate the remaining space as padding between tiles. background-position is ignored
// as per the spec, so the position is just the box origin. We are also ignoring
// background-attachment here, which seems unspecced when combined with
// background-repeat: space.
let space_for_middle_tiles = image_size * num_middle_tiles;
*tile_spacing = (size_remaining - space_for_middle_tiles) / (num_middle_tiles + 1);
}
/// Tile an image
pub fn tile_image(position: &mut Au,
size: &mut Au,
absolute_anchor_origin: Au,
image_size: Au) {
// Avoid division by zero below!
if image_size == Au(0) {
return
}
let delta_pixels = absolute_anchor_origin - *position;
let image_size_px = image_size.to_f32_px();
let tile_count = ((delta_pixels.to_f32_px() + image_size_px - 1.0) / image_size_px).floor();
let offset = image_size * (tile_count as i32);
let new_position = absolute_anchor_origin - offset;
*size = *position - new_position + *size;
*position = new_position;
}
}
/// A fragment that represents an inline frame (iframe). This stores the pipeline ID so that the
/// size of this iframe can be communicated via the constellation to the iframe's own layout thread.
#[derive(Clone)]
pub struct IframeFragmentInfo {
/// The pipeline ID of this iframe.
pub pipeline_id: PipelineId,
}
impl IframeFragmentInfo {
/// Creates the information specific to an iframe fragment.
pub fn new<N: ThreadSafeLayoutNode>(node: &N) -> IframeFragmentInfo {
let pipeline_id = node.iframe_pipeline_id();
IframeFragmentInfo {
pipeline_id: pipeline_id,
}
}
}
/// A scanned text fragment represents a single run of text with a distinct style. A `TextFragment`
/// may be split into two or more fragments across line breaks. Several `TextFragment`s may
/// correspond to a single DOM text node. Split text fragments are implemented by referring to
/// subsets of a single `TextRun` object.
#[derive(Clone)]
pub struct ScannedTextFragmentInfo {
/// The text run that this represents.
pub run: Arc<TextRun>,
/// The intrinsic size of the text fragment.
pub content_size: LogicalSize<Au>,
/// The byte offset of the insertion point, if any.
pub insertion_point: Option<ByteIndex>,
/// The range within the above text run that this represents.
pub range: Range<ByteIndex>,
/// The endpoint of the above range, including whitespace that was stripped out. This exists
/// so that we can restore the range to its original value (before line breaking occurred) when
/// performing incremental reflow.
pub range_end_including_stripped_whitespace: ByteIndex,
pub flags: ScannedTextFlags,
}
bitflags! {
pub flags ScannedTextFlags: u8 {
/// Whether a line break is required after this fragment if wrapping on newlines (e.g. if
/// `white-space: pre` is in effect).
const REQUIRES_LINE_BREAK_AFTERWARD_IF_WRAPPING_ON_NEWLINES = 0x01,
/// Is this fragment selected?
const SELECTED = 0x02,
}
}
impl ScannedTextFragmentInfo {
/// Creates the information specific to a scanned text fragment from a range and a text run.
pub fn new(run: Arc<TextRun>,
range: Range<ByteIndex>,
content_size: LogicalSize<Au>,
insertion_point: Option<ByteIndex>,
flags: ScannedTextFlags)
-> ScannedTextFragmentInfo {
ScannedTextFragmentInfo {
run: run,
range: range,
insertion_point: insertion_point,
content_size: content_size,
range_end_including_stripped_whitespace: range.end(),
flags: flags,
}
}
pub fn text(&self) -> &str {
&self.run.text[self.range.begin().to_usize() .. self.range.end().to_usize()]
}
pub fn requires_line_break_afterward_if_wrapping_on_newlines(&self) -> bool {
self.flags.contains(REQUIRES_LINE_BREAK_AFTERWARD_IF_WRAPPING_ON_NEWLINES)
}
pub fn selected(&self) -> bool {
self.flags.contains(SELECTED)
}
}
/// Describes how to split a fragment. This is used during line breaking as part of the return
/// value of `find_split_info_for_inline_size()`.
#[derive(Debug, Clone)]
pub struct SplitInfo {
// TODO(bjz): this should only need to be a single character index, but both values are
// currently needed for splitting in the `inline::try_append_*` functions.
pub range: Range<ByteIndex>,
pub inline_size: Au,
}
impl SplitInfo {
fn new(range: Range<ByteIndex>, info: &ScannedTextFragmentInfo) -> SplitInfo {
let inline_size = info.run.advance_for_range(&range);
SplitInfo {
range: range,
inline_size: inline_size,
}
}
}
/// Describes how to split a fragment into two. This contains up to two `SplitInfo`s.
pub struct SplitResult {
/// The part of the fragment that goes on the first line.
pub inline_start: Option<SplitInfo>,
/// The part of the fragment that goes on the second line.
pub inline_end: Option<SplitInfo>,
/// The text run which is being split.
pub text_run: Arc<TextRun>,
}
/// Describes how a fragment should be truncated.
struct TruncationResult {
/// The part of the fragment remaining after truncation.
split: SplitInfo,
/// The text run which is being truncated.
text_run: Arc<TextRun>,
}
/// Data for an unscanned text fragment. Unscanned text fragments are the results of flow
/// construction that have not yet had their inline-size determined.
#[derive(Clone)]
pub struct UnscannedTextFragmentInfo {
/// The text inside the fragment.
pub text: Box<str>,
/// The selected text range. An empty range represents the insertion point.
pub selection: Option<Range<ByteIndex>>,
}
impl UnscannedTextFragmentInfo {
/// Creates a new instance of `UnscannedTextFragmentInfo` from the given text.
#[inline]
pub fn new(text: String, selection: Option<Range<ByteIndex>>) -> UnscannedTextFragmentInfo {
UnscannedTextFragmentInfo {
text: text.into_boxed_str(),
selection: selection,
}
}
}
/// A fragment that represents a table column.
#[derive(Copy, Clone)]
pub struct TableColumnFragmentInfo {
/// the number of columns a <col> element should span
pub span: u32,
}
impl TableColumnFragmentInfo {
/// Create the information specific to an table column fragment.
pub fn new<N: ThreadSafeLayoutNode>(node: &N) -> TableColumnFragmentInfo {
let element = node.as_element().unwrap();
let span = element.get_attr(&ns!(), &local_name!("span"))
.and_then(|string| string.parse().ok())
.unwrap_or(0);
TableColumnFragmentInfo {
span: span,
}
}
}
/// A wrapper for fragments that have been truncated by the `text-overflow` property.
/// This may have an associated text node, or, if the fragment was completely truncated,
/// it may act as an invisible marker for incremental reflow.
#[derive(Clone)]
pub struct TruncatedFragmentInfo {
pub text_info: Option<ScannedTextFragmentInfo>,
pub full: Fragment,
}
impl Fragment {
/// Constructs a new `Fragment` instance.
pub fn new<N: ThreadSafeLayoutNode>(node: &N, specific: SpecificFragmentInfo, ctx: &LayoutContext) -> Fragment {
let shared_context = ctx.shared_context();
let style = node.style(shared_context);
let writing_mode = style.writing_mode;
let mut restyle_damage = node.restyle_damage();
restyle_damage.remove(RECONSTRUCT_FLOW);
Fragment {
node: node.opaque(),
style: style,
selected_style: node.selected_style(),
restyle_damage: restyle_damage,
border_box: LogicalRect::zero(writing_mode),
border_padding: LogicalMargin::zero(writing_mode),
margin: LogicalMargin::zero(writing_mode),
specific: specific,
inline_context: None,
pseudo: node.get_pseudo_element_type().strip(),
flags: FragmentFlags::empty(),
debug_id: DebugId::new(),
stacking_context_id: StackingContextId::new(0),
}
}
/// Constructs a new `Fragment` instance from an opaque node.
pub fn from_opaque_node_and_style(node: OpaqueNode,
pseudo: PseudoElementType<()>,
style: Arc<ServoComputedValues>,
selected_style: Arc<ServoComputedValues>,
mut restyle_damage: RestyleDamage,
specific: SpecificFragmentInfo)
-> Fragment {
let writing_mode = style.writing_mode;
restyle_damage.remove(RECONSTRUCT_FLOW);
Fragment {
node: node,
style: style,
selected_style: selected_style,
restyle_damage: restyle_damage,
border_box: LogicalRect::zero(writing_mode),
border_padding: LogicalMargin::zero(writing_mode),
margin: LogicalMargin::zero(writing_mode),
specific: specific,
inline_context: None,
pseudo: pseudo,
flags: FragmentFlags::empty(),
debug_id: DebugId::new(),
stacking_context_id: StackingContextId::new(0),
}
}
/// Creates an anonymous fragment just like this one but with the given style and fragment
/// type. For the new anonymous fragment, layout-related values (border box, etc.) are reset to
/// initial values.
pub fn create_similar_anonymous_fragment(&self,
style: Arc<ServoComputedValues>,
specific: SpecificFragmentInfo)
-> Fragment {
let writing_mode = style.writing_mode;
Fragment {
node: self.node,
style: style,
selected_style: self.selected_style.clone(),
restyle_damage: self.restyle_damage,
border_box: LogicalRect::zero(writing_mode),
border_padding: LogicalMargin::zero(writing_mode),
margin: LogicalMargin::zero(writing_mode),
specific: specific,
inline_context: None,
pseudo: self.pseudo,
flags: FragmentFlags::empty(),
debug_id: DebugId::new(),
stacking_context_id: StackingContextId::new(0),
}
}
/// Transforms this fragment into another fragment of the given type, with the given size,
/// preserving all the other data.
pub fn transform(&self, size: LogicalSize<Au>, info: SpecificFragmentInfo)
-> Fragment {
let new_border_box = LogicalRect::from_point_size(self.style.writing_mode,
self.border_box.start,
size);
let mut restyle_damage = RestyleDamage::rebuild_and_reflow();
restyle_damage.remove(RECONSTRUCT_FLOW);
Fragment {
node: self.node,
style: self.style.clone(),
selected_style: self.selected_style.clone(),
restyle_damage: restyle_damage,
border_box: new_border_box,
border_padding: self.border_padding,
margin: self.margin,
specific: info,
inline_context: self.inline_context.clone(),
pseudo: self.pseudo.clone(),
flags: FragmentFlags::empty(),
debug_id: self.debug_id.clone(),
stacking_context_id: StackingContextId::new(0),
}
}
/// Transforms this fragment using the given `SplitInfo`, preserving all the other data.
pub fn transform_with_split_info(&self, split: &SplitInfo, text_run: Arc<TextRun>)
-> Fragment {
let size = LogicalSize::new(self.style.writing_mode,
split.inline_size,
self.border_box.size.block);
// Preserve the insertion point if it is in this fragment's range or it is at line end.
let (flags, insertion_point) = match self.specific {
SpecificFragmentInfo::ScannedText(ref info) => {
match info.insertion_point {
Some(index) if split.range.contains(index) => (info.flags, info.insertion_point),
Some(index) if index == ByteIndex(text_run.text.chars().count() as isize - 1) &&
index == split.range.end() => (info.flags, info.insertion_point),
_ => (info.flags, None)
}
},
_ => (ScannedTextFlags::empty(), None)
};
let info = box ScannedTextFragmentInfo::new(
text_run,
split.range,
size,
insertion_point,
flags);
self.transform(size, SpecificFragmentInfo::ScannedText(info))
}
/// Transforms this fragment into an ellipsis fragment, preserving all the other data.
pub fn transform_into_ellipsis(&self,
layout_context: &LayoutContext,
text_overflow_string: String)
-> Fragment {
let mut unscanned_ellipsis_fragments = LinkedList::new();
let mut ellipsis_fragment = self.transform(
self.border_box.size,
SpecificFragmentInfo::UnscannedText(
box UnscannedTextFragmentInfo::new(text_overflow_string, None)));
unscanned_ellipsis_fragments.push_back(ellipsis_fragment);
let ellipsis_fragments = with_thread_local_font_context(layout_context, |font_context| {
TextRunScanner::new().scan_for_runs(font_context, unscanned_ellipsis_fragments)
});
debug_assert!(ellipsis_fragments.len() == 1);
ellipsis_fragment = ellipsis_fragments.fragments.into_iter().next().unwrap();
ellipsis_fragment.flags |= IS_ELLIPSIS;
ellipsis_fragment
}
pub fn restyle_damage(&self) -> RestyleDamage {
self.restyle_damage | self.specific.restyle_damage()
}
pub fn contains_node(&self, node_address: OpaqueNode) -> bool {
node_address == self.node ||
self.inline_context.as_ref().map_or(false, |ctx| {
ctx.contains_node(node_address)
})
}
/// Adds a style to the inline context for this fragment. If the inline context doesn't exist
/// yet, it will be created.
pub fn add_inline_context_style(&mut self, node_info: InlineFragmentNodeInfo) {
if self.inline_context.is_none() {
self.inline_context = Some(InlineFragmentContext::new());
}
self.inline_context.as_mut().unwrap().nodes.push(node_info);
}
/// Determines which quantities (border/padding/margin/specified) should be included in the
/// intrinsic inline size of this fragment.
fn quantities_included_in_intrinsic_inline_size(&self)
-> QuantitiesIncludedInIntrinsicInlineSizes {
match self.specific {
SpecificFragmentInfo::Canvas(_) |
SpecificFragmentInfo::Generic |
SpecificFragmentInfo::GeneratedContent(_) |
SpecificFragmentInfo::Iframe(_) |
SpecificFragmentInfo::Image(_) |
SpecificFragmentInfo::InlineAbsolute(_) |
SpecificFragmentInfo::Multicol |
SpecificFragmentInfo::Svg(_) => {
QuantitiesIncludedInIntrinsicInlineSizes::all()
}
SpecificFragmentInfo::Table => {
INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED |
INTRINSIC_INLINE_SIZE_INCLUDES_PADDING |
INTRINSIC_INLINE_SIZE_INCLUDES_BORDER
}
SpecificFragmentInfo::TableCell => {
let base_quantities = INTRINSIC_INLINE_SIZE_INCLUDES_PADDING |
INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED;
if self.style.get_inheritedtable().border_collapse ==
border_collapse::T::separate {
base_quantities | INTRINSIC_INLINE_SIZE_INCLUDES_BORDER
} else {
base_quantities
}
}
SpecificFragmentInfo::TableWrapper => {
let base_quantities = INTRINSIC_INLINE_SIZE_INCLUDES_MARGINS |
INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED;
if self.style.get_inheritedtable().border_collapse ==
border_collapse::T::separate {
base_quantities | INTRINSIC_INLINE_SIZE_INCLUDES_BORDER
} else {
base_quantities
}
}
SpecificFragmentInfo::TableRow => {
let base_quantities = INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED;
if self.style.get_inheritedtable().border_collapse ==
border_collapse::T::separate {
base_quantities | INTRINSIC_INLINE_SIZE_INCLUDES_BORDER
} else {
base_quantities
}
}
SpecificFragmentInfo::TruncatedFragment(_) |
SpecificFragmentInfo::ScannedText(_) |
SpecificFragmentInfo::TableColumn(_) |
SpecificFragmentInfo::UnscannedText(_) |
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) |
SpecificFragmentInfo::InlineBlock(_) |
SpecificFragmentInfo::MulticolColumn => {
QuantitiesIncludedInIntrinsicInlineSizes::empty()
}
}
}
/// Returns the portion of the intrinsic inline-size that consists of borders/padding and
/// margins, respectively.
///
/// FIXME(#2261, pcwalton): This won't work well for inlines: is this OK?
pub fn surrounding_intrinsic_inline_size(&self) -> (Au, Au) {
let flags = self.quantities_included_in_intrinsic_inline_size();
let style = self.style();
// FIXME(pcwalton): Percentages should be relative to any definite size per CSS-SIZING.
// This will likely need to be done by pushing down definite sizes during selector
// cascading.
let margin = if flags.contains(INTRINSIC_INLINE_SIZE_INCLUDES_MARGINS) {
let margin = style.logical_margin();
(MaybeAuto::from_style(margin.inline_start, Au(0)).specified_or_zero() +
MaybeAuto::from_style(margin.inline_end, Au(0)).specified_or_zero())
} else {
Au(0)
};
// FIXME(pcwalton): Percentages should be relative to any definite size per CSS-SIZING.
// This will likely need to be done by pushing down definite sizes during selector
// cascading.
let padding = if flags.contains(INTRINSIC_INLINE_SIZE_INCLUDES_PADDING) {
let padding = style.logical_padding();
(model::specified(padding.inline_start, Au(0)) +
model::specified(padding.inline_end, Au(0)))
} else {
Au(0)
};
let border = if flags.contains(INTRINSIC_INLINE_SIZE_INCLUDES_BORDER) {
self.border_width().inline_start_end()
} else {
Au(0)
};
(border + padding, margin)
}
/// Uses the style only to estimate the intrinsic inline-sizes. These may be modified for text
/// or replaced elements.
pub fn style_specified_intrinsic_inline_size(&self) -> IntrinsicISizesContribution {
let flags = self.quantities_included_in_intrinsic_inline_size();
let style = self.style();
// FIXME(#2261, pcwalton): This won't work well for inlines: is this OK?
let (border_padding, margin) = self.surrounding_intrinsic_inline_size();
let mut specified = Au(0);
if flags.contains(INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED) {
specified = MaybeAuto::from_style(style.content_inline_size(),
Au(0)).specified_or_zero();
specified = max(model::specified(style.min_inline_size(), Au(0)), specified);
if let Some(max) = model::specified_or_none(style.max_inline_size(), Au(0)) {
specified = min(specified, max)
}
if self.style.get_position().box_sizing == box_sizing::T::border_box {
specified -= border_padding
}
}
IntrinsicISizesContribution {
content_intrinsic_sizes: IntrinsicISizes {
minimum_inline_size: specified,
preferred_inline_size: specified,
},
surrounding_size: border_padding + margin,
}
}
/// intrinsic width of this replaced element.
#[inline]
pub fn intrinsic_width(&self) -> Au {
match self.specific {
SpecificFragmentInfo::Image(ref info) => {
if let Some(ref data) = info.metadata {
Au::from_px(data.width as i32)
} else {
Au(0)
}
}
SpecificFragmentInfo::Canvas(ref info) => info.dom_width,
SpecificFragmentInfo::Svg(ref info) => info.dom_width,
// Note: Currently for replaced element with no intrinsic size,
// this function simply returns the default object size. As long as
// these elements do not have intrinsic aspect ratio this should be
// sufficient, but we may need to investigate if this is enough for
// use cases like SVG.
SpecificFragmentInfo::Iframe(_) => Au::from_px(DEFAULT_REPLACED_WIDTH),
_ => panic!("Trying to get intrinsic width on non-replaced element!")
}
}
/// intrinsic width of this replaced element.
#[inline]
pub fn intrinsic_height(&self) -> Au {
match self.specific {
SpecificFragmentInfo::Image(ref info) => {
if let Some(ref data) = info.metadata {
Au::from_px(data.height as i32)
} else {
Au(0)
}
}
SpecificFragmentInfo::Canvas(ref info) => info.dom_height,
SpecificFragmentInfo::Svg(ref info) => info.dom_height,
SpecificFragmentInfo::Iframe(_) => Au::from_px(DEFAULT_REPLACED_HEIGHT),
_ => panic!("Trying to get intrinsic height on non-replaced element!")
}
}
/// Whether this replace element has intrinsic aspect ratio.
pub fn has_intrinsic_ratio(&self) -> bool {
match self.specific {
SpecificFragmentInfo::Image(_) |
SpecificFragmentInfo::Canvas(_) |
// TODO(stshine): According to the SVG spec, whether a SVG element has intrinsic
// aspect ratio is determined by the `preserveAspectRatio` attribute. Since for