Fix text positioning in bevy_ui

crates/bevy_text/src/pipeline.rs

@@ -59,16 +59,16 @@ impl TextPipeline {
         let first_glyph = section_glyphs.first().unwrap();
         let mut min_x: f32 = first_glyph.glyph.position.x - scaled_font.h_side_bearing(first_glyph.glyph.id);
         let mut min_y: f32 = first_glyph.glyph.position.y - scaled_font.ascent();
-        let mut max_x: f32 = 0.0;
-        let mut max_y: f32 = 0.0;
+        let mut max_x: f32 = first_glyph.glyph.position.x + scaled_font.h_advance(first_glyph.glyph.id);
+        let mut max_y: f32 = first_glyph.glyph.position.y - scaled_font.descent();
         for section_glyph in section_glyphs.iter() {
             let glyph = &section_glyph.glyph;
             min_x = min_x.min(glyph.position.x - scaled_font.h_side_bearing(glyph.id));
             min_y = min_y.min(glyph.position.y - scaled_font.ascent());
             max_x = max_x.max(glyph.position.x + scaled_font.h_advance(glyph.id));
             max_y = max_y.max(glyph.position.y - scaled_font.descent());
         }
-        let size = Size::new(max_x - min_x, max_y - min_y - scaled_font.descent());
+        let size = Size::new(max_x - min_x, max_y - min_y);
         Ok(size)
     }
 

crates/bevy_ui/src/widget/text.rs

@@ -25,6 +25,21 @@ pub struct Text {
     pub style: TextStyle,
 }
 
+/// Defines how min_size, size, and max_size affects the bounds of a text 
+/// block. 
+pub fn text_constraint(min_size: Val, size: Val, max_size: Val) -> f32 {
+    // Needs support for percentages
+    match (min_size, size, max_size) {
+        (_, _, Val::Px(max)) => max,
+        (Val::Px(min), _, _) => min,
+        (Val::Undefined, Val::Px(size), Val::Undefined) => size,
+        (Val::Auto, Val::Px(size), Val::Auto) => size,
+        _ => f32::MAX,
+    }
+}
+
+/// Computes the size of a text block and updates the TextVertices with the
+/// new computed vertices
 pub fn text_system(
     mut textures: ResMut<Assets<Texture>>,
     fonts: Res<Assets<Font>>,
@@ -39,18 +54,8 @@ pub fn text_system(
 ) {
     for ((text, style), mut vertices, mut calculated_size) in &mut text_query.iter() {
         let node_size = Size::new(
-            match style.size.width {
-                Val::Auto => f32::MAX,
-                Val::Undefined => f32::MAX,
-                Val::Px(num) => num,
-                Val::Percent(_) => f32::MAX, // TODO: support percentages
-            },
-            match style.size.height {
-                Val::Auto => f32::MAX,
-                Val::Undefined => f32::MAX,
-                Val::Px(num) => num,
-                Val::Percent(_) => f32::MAX, // TODO: support percentages
-            },
+            text_constraint(style.min_size.width, style.size.width, style.max_size.width), 
+            text_constraint(style.min_size.height, style.size.height, style.max_size.height), 
         );
 
         if let Err(e) = text_pipeline.queue_text(

examples/ui/text_debug.rs

@@ -49,15 +49,15 @@ fn infotext_system(mut commands: Commands, asset_server: Res<AssetServer>) {
                     right: Val::Px(15.0),
                     ..Default::default()
                 },
-                size: Size {
-                    width: Val::Px(400.0),
-                    ..Default::default()
+                max_size: Size {
+                    width: Val::Px(400.),
+                    height: Val::Undefined,
                 },
                 ..Default::default()
             },
             text: Text {
                 value:
-                    "This is very long text with limited width in the top right and is also pink"
+                    "This is very long text with limited width in the top right and is also pink" 
                         .to_string(),
                 font: font.clone(),
                 style: TextStyle {