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Enhance label sizing algorithm
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@RandomShaper
RandomShaper committed Feb 6, 2023
1 parent 1ed549e commit 5131b81
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Showing 2 changed files with 59 additions and 56 deletions.
112 changes: 58 additions & 54 deletions scene/gui/label.cpp
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Expand Up @@ -87,6 +87,8 @@ int Label::get_line_height(int p_line) const {
}

void Label::_shape() {
bool font_was_dirty = font_dirty;

Ref<StyleBox> style = theme_cache.normal_style;
int width = (get_size().width - style->get_minimum_size().width);

Expand Down Expand Up @@ -128,7 +130,24 @@ void Label::_shape() {
TS->free_rid(lines_rid[i]);
}
lines_rid.clear();
}

Size2i prev_minsize = minsize;
minsize = Size2();

if (xl_text.length() == 0) {
lines_dirty = false;
return;
}

// Don't compute minimum size until width is stable (two shape requests in a row with the same width.)
// This avoids situations in which the initial width is very narrow and the label would break text
// into many very short lines, causing a very tall label that can leave a deformed container.
bool width_stabilized = get_size().width == stable_width;
stable_width = get_size().width;

// With autowrap off, there's still a point in shaping before width is stable: to contribute a min width.
if (lines_dirty && (width_stabilized || autowrap_mode == TextServer::AUTOWRAP_OFF)) {
BitField<TextServer::LineBreakFlag> autowrap_flags = TextServer::BREAK_MANDATORY;
switch (autowrap_mode) {
case TextServer::AUTOWRAP_WORD_SMART:
Expand All @@ -152,21 +171,15 @@ void Label::_shape() {
}
}

if (xl_text.length() == 0) {
minsize = Size2(1, get_line_height());
return;
}

if (autowrap_mode == TextServer::AUTOWRAP_OFF) {
minsize.width = 0.0f;
for (int i = 0; i < lines_rid.size(); i++) {
if (minsize.width < TS->shaped_text_get_size(lines_rid[i]).x) {
minsize.width = TS->shaped_text_get_size(lines_rid[i]).x;
}
}
}

if (lines_dirty) {
if (lines_dirty && width_stabilized) {
BitField<TextServer::TextOverrunFlag> overrun_flags = TextServer::OVERRUN_NO_TRIM;
switch (overrun_behavior) {
case TextServer::OVERRUN_TRIM_WORD_ELLIPSIS:
Expand All @@ -191,8 +204,11 @@ void Label::_shape() {

// Fill after min_size calculation.

int visible_lines = lines_rid.size();
if (max_lines_visible >= 0 && visible_lines > max_lines_visible) {
visible_lines = max_lines_visible;
}
if (autowrap_mode != TextServer::AUTOWRAP_OFF) {
int visible_lines = get_visible_line_count();
bool lines_hidden = visible_lines > 0 && visible_lines < lines_rid.size();
if (lines_hidden) {
overrun_flags.set_flag(TextServer::OVERRUN_ENFORCE_ELLIPSIS);
Expand Down Expand Up @@ -221,33 +237,22 @@ void Label::_shape() {
}
}
}
lines_dirty = false;
lines_shaped_last_width = get_size().width;
}

_update_visible();
int last_line = MIN(lines_rid.size(), visible_lines + lines_skipped);
int line_spacing = settings.is_valid() ? settings->get_line_spacing() : theme_cache.line_spacing;
for (int64_t i = lines_skipped; i < last_line; i++) {
minsize.height += TS->shaped_text_get_size(lines_rid[i]).y + line_spacing;
}

if (autowrap_mode == TextServer::AUTOWRAP_OFF || !clip || overrun_behavior == TextServer::OVERRUN_NO_TRIMMING) {
update_minimum_size();
lines_dirty = false;
}
}

void Label::_update_visible() {
int line_spacing = settings.is_valid() ? settings->get_line_spacing() : theme_cache.line_spacing;
Ref<StyleBox> style = theme_cache.normal_style;
int lines_visible = lines_rid.size();

if (max_lines_visible >= 0 && lines_visible > max_lines_visible) {
lines_visible = max_lines_visible;
if (minsize != prev_minsize || font_was_dirty) {
update_minimum_size();
}

minsize.height = 0;
int last_line = MIN(lines_rid.size(), lines_visible + lines_skipped);
for (int64_t i = lines_skipped; i < last_line; i++) {
minsize.height += TS->shaped_text_get_size(lines_rid[i]).y + line_spacing;
if (minsize.height > (get_size().height - style->get_minimum_size().height + line_spacing)) {
break;
}
if (!width_stabilized) {
callable_mp(this, &Label::_shape).call_deferred();
}
}

Expand Down Expand Up @@ -347,6 +352,11 @@ void Label::_notification(int p_what) {

if (dirty || font_dirty || lines_dirty) {
_shape();
if (lines_dirty) {
// There will be another pass.
queue_redraw();
break;
}
}

RID ci = get_canvas_item();
Expand All @@ -370,22 +380,22 @@ void Label::_notification(int p_what) {
style->draw(ci, Rect2(Point2(0, 0), get_size()));

float total_h = 0.0;
int lines_visible = 0;
int visible_lines = 0;

// Get number of lines to fit to the height.
for (int64_t i = lines_skipped; i < lines_rid.size(); i++) {
total_h += TS->shaped_text_get_size(lines_rid[i]).y + line_spacing;
if (total_h > (get_size().height - style->get_minimum_size().height + line_spacing)) {
break;
}
lines_visible++;
visible_lines++;
}

if (max_lines_visible >= 0 && lines_visible > max_lines_visible) {
lines_visible = max_lines_visible;
if (max_lines_visible >= 0 && visible_lines > max_lines_visible) {
visible_lines = max_lines_visible;
}

int last_line = MIN(lines_rid.size(), lines_visible + lines_skipped);
int last_line = MIN(lines_rid.size(), visible_lines + lines_skipped);
bool trim_chars = (visible_chars >= 0) && (visible_chars_behavior == TextServer::VC_CHARS_AFTER_SHAPING);
bool trim_glyphs_ltr = (visible_chars >= 0) && ((visible_chars_behavior == TextServer::VC_GLYPHS_LTR) || ((visible_chars_behavior == TextServer::VC_GLYPHS_AUTO) && !rtl_layout));
bool trim_glyphs_rtl = (visible_chars >= 0) && ((visible_chars_behavior == TextServer::VC_GLYPHS_RTL) || ((visible_chars_behavior == TextServer::VC_GLYPHS_AUTO) && rtl_layout));
Expand All @@ -402,7 +412,7 @@ void Label::_notification(int p_what) {
total_h += style->get_margin(SIDE_TOP) + style->get_margin(SIDE_BOTTOM);

int vbegin = 0, vsep = 0;
if (lines_visible > 0) {
if (visible_lines > 0) {
switch (vertical_alignment) {
case VERTICAL_ALIGNMENT_TOP: {
// Nothing.
Expand All @@ -419,8 +429,8 @@ void Label::_notification(int p_what) {
} break;
case VERTICAL_ALIGNMENT_FILL: {
vbegin = 0;
if (lines_visible > 1) {
vsep = (size.y - (total_h - line_spacing)) / (lines_visible - 1);
if (visible_lines > 1) {
vsep = (size.y - (total_h - line_spacing)) / (visible_lines - 1);
} else {
vsep = 0;
}
Expand Down Expand Up @@ -597,13 +607,7 @@ void Label::_notification(int p_what) {
} break;

case NOTIFICATION_RESIZED: {
// It may happen that the reshaping due to this size change triggers a cascade of re-layout
// across the hierarchy where this label belongs to in a way that its size changes multiple
// times, but ending up with the original size it was already shaped for.
// This check prevents the catastrophic, freezing infinite cascade of re-layout.
if (lines_shaped_last_width != get_size().width) {
lines_dirty = true;
}
lines_dirty = true;
} break;
}
}
Expand Down Expand Up @@ -646,25 +650,25 @@ int Label::get_line_count() const {
int Label::get_visible_line_count() const {
Ref<StyleBox> style = theme_cache.normal_style;
int line_spacing = settings.is_valid() ? settings->get_line_spacing() : theme_cache.line_spacing;
int lines_visible = 0;
int visible_lines = 0;
float total_h = 0.0;
for (int64_t i = lines_skipped; i < lines_rid.size(); i++) {
total_h += TS->shaped_text_get_size(lines_rid[i]).y + line_spacing;
if (total_h > (get_size().height - style->get_minimum_size().height + line_spacing)) {
break;
}
lines_visible++;
visible_lines++;
}

if (lines_visible > lines_rid.size()) {
lines_visible = lines_rid.size();
if (visible_lines > lines_rid.size()) {
visible_lines = lines_rid.size();
}

if (max_lines_visible >= 0 && lines_visible > max_lines_visible) {
lines_visible = max_lines_visible;
if (max_lines_visible >= 0 && visible_lines > max_lines_visible) {
visible_lines = max_lines_visible;
}

return lines_visible;
return visible_lines;
}

void Label::set_horizontal_alignment(HorizontalAlignment p_alignment) {
Expand Down Expand Up @@ -886,7 +890,7 @@ void Label::set_lines_skipped(int p_lines) {
}

lines_skipped = p_lines;
_update_visible();
lines_dirty = true;
queue_redraw();
}

Expand All @@ -900,7 +904,7 @@ void Label::set_max_lines_visible(int p_lines) {
}

max_lines_visible = p_lines;
_update_visible();
lines_dirty = true;
queue_redraw();
}

Expand Down Expand Up @@ -949,7 +953,7 @@ void Label::_bind_methods() {
ClassDB::bind_method(D_METHOD("get_visible_ratio"), &Label::get_visible_ratio);
ClassDB::bind_method(D_METHOD("set_lines_skipped", "lines_skipped"), &Label::set_lines_skipped);
ClassDB::bind_method(D_METHOD("get_lines_skipped"), &Label::get_lines_skipped);
ClassDB::bind_method(D_METHOD("set_max_lines_visible", "lines_visible"), &Label::set_max_lines_visible);
ClassDB::bind_method(D_METHOD("set_max_lines_visible", "visible_lines"), &Label::set_max_lines_visible);
ClassDB::bind_method(D_METHOD("get_max_lines_visible"), &Label::get_max_lines_visible);
ClassDB::bind_method(D_METHOD("set_structured_text_bidi_override", "parser"), &Label::set_structured_text_bidi_override);
ClassDB::bind_method(D_METHOD("get_structured_text_bidi_override"), &Label::get_structured_text_bidi_override);
Expand Down
3 changes: 1 addition & 2 deletions scene/gui/label.h
View file
Expand Up @@ -46,10 +46,10 @@ class Label : public Control {
bool clip = false;
TextServer::OverrunBehavior overrun_behavior = TextServer::OVERRUN_NO_TRIMMING;
Size2 minsize;
real_t stable_width = -1;
bool uppercase = false;

bool lines_dirty = true;
int lines_shaped_last_width = -1;

bool dirty = true;
bool font_dirty = true;
Expand Down Expand Up @@ -83,7 +83,6 @@ class Label : public Control {
int font_shadow_outline_size;
} theme_cache;

void _update_visible();
void _shape();
void _invalidate();

Expand Down

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