Reuse TextLayoutInfo in queue_text (#14997)

# Objective

Don't reallocate `TextLayoutInfo` every time it needs to be updated.

## Solution

Reuse existing allocation.

crates/bevy_text/src/pipeline.rs

@@ -145,6 +145,7 @@ impl TextPipeline {
  #[allow(clippy::too_many_arguments)]
  pub fn queue_text(
  &mut self,
+ layout_info: &mut TextLayoutInfo,
  fonts: &Assets<Font>,
  sections: &[TextSection],
  scale_factor: f64,
@@ -156,9 +157,12 @@ impl TextPipeline {
  textures: &mut Assets<Image>,
  y_axis_orientation: YAxisOrientation,
  buffer: &mut CosmicBuffer,
- ) -> Result<TextLayoutInfo, TextError> {
+ ) -> Result<(), TextError> {
+ layout_info.glyphs.clear();
+ layout_info.size = Default::default();
+
  if sections.is_empty() {
- return Ok(TextLayoutInfo::default());
+ return Ok(());
  }
 
  self.update_buffer(
@@ -175,14 +179,14 @@ impl TextPipeline {
  let font_system = &mut self.font_system.0;
  let swash_cache = &mut self.swash_cache.0;
 
- let glyphs = buffer
+ buffer
  .layout_runs()
  .flat_map(|run| {
  run.glyphs
  .iter()
  .map(move |layout_glyph| (layout_glyph, run.line_y))
  })
- .map(|(layout_glyph, line_y)| {
+ .try_for_each(|(layout_glyph, line_y)| {
  let section_index = layout_glyph.metadata;
 
  let font_handle = sections[section_index].style.font.clone_weak();
@@ -224,14 +228,12 @@ impl TextPipeline {
  // when glyphs are not limited to single byte representation, relevant for #1319
  let pos_glyph =
  PositionedGlyph::new(position, glyph_size.as_vec2(), atlas_info, section_index);
- Ok(pos_glyph)
- })
- .collect::<Result<Vec<_>, _>>()?;
+ layout_info.glyphs.push(pos_glyph);
+  Ok(())
+ })?;
 
- Ok(TextLayoutInfo {
- glyphs,
- size: box_size,
- })
+ layout_info.size = box_size;
+ Ok(())
  }
 
  /// Queues text for measurement

crates/bevy_text/src/text2d.rs

@@ -170,7 +170,7 @@ pub fn update_text2d_layout(
 
  let inverse_scale_factor = scale_factor.recip();
 
- for (entity, text, bounds, mut text_layout_info, mut buffer) in &mut text_query {
+ for (entity, text, bounds, text_layout_info, mut buffer) in &mut text_query {
  if factor_changed || text.is_changed() || bounds.is_changed() || queue.remove(&entity) {
  let text_bounds = TextBounds {
  width: if text.linebreak_behavior == BreakLineOn::NoWrap {
@@ -183,7 +183,9 @@ pub fn update_text2d_layout(
  .map(|height| scale_value(height, scale_factor)),
  };
 
+ let text_layout_info = text_layout_info.into_inner();
  match text_pipeline.queue_text(
+ text_layout_info,
  &fonts,
  &text.sections,
  scale_factor.into(),
@@ -204,10 +206,11 @@ pub fn update_text2d_layout(
  Err(e @ (TextError::FailedToAddGlyph(_) | TextError::FailedToGetGlyphImage(_))) => {
  panic!("Fatal error when processing text: {e}.");
  }
- Ok(mut info) => {
- info.size.x = scale_value(info.size.x, inverse_scale_factor);
- info.size.y = scale_value(info.size.y, inverse_scale_factor);
- *text_layout_info = info;
+ Ok(()) => {
+ text_layout_info.size.x =
+ scale_value(text_layout_info.size.x, inverse_scale_factor);
+ text_layout_info.size.y =
+ scale_value(text_layout_info.size.y, inverse_scale_factor);
  }
  }
  }

crates/bevy_ui/src/widget/text.rs

@@ -224,7 +224,7 @@ fn queue_text(
  text: &Text,
  node: Ref<Node>,
  mut text_flags: Mut<TextFlags>,
- mut text_layout_info: Mut<TextLayoutInfo>,
+ text_layout_info: Mut<TextLayoutInfo>,
  buffer: &mut CosmicBuffer,
 ) {
  // Skip the text node if it is waiting for a new measure func
@@ -240,7 +240,9 @@ fn queue_text(
  )
  };
 
+ let text_layout_info = text_layout_info.into_inner();
  match text_pipeline.queue_text(
+ text_layout_info,
  fonts,
  &text.sections,
  scale_factor.into(),
@@ -260,10 +262,11 @@ fn queue_text(
  Err(e @ (TextError::FailedToAddGlyph(_) | TextError::FailedToGetGlyphImage(_))) => {
  panic!("Fatal error when processing text: {e}.");
  }
- Ok(mut info) => {
- info.size.x = scale_value(info.size.x, inverse_scale_factor);
- info.size.y = scale_value(info.size.y, inverse_scale_factor);
- *text_layout_info = info;
+ Ok(()) => {
+ text_layout_info.size.x =
+ scale_value(text_layout_info.size.x, inverse_scale_factor);
+ text_layout_info.size.y =
+ scale_value(text_layout_info.size.y, inverse_scale_factor);
  text_flags.needs_recompute = false;
  }
  }