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;
             }
         }