HIDPI Text (#1132)

HIDPI Text 
* add more operator overloads to `bevy::math::Size`
* render UI text at physical resolution

crates/bevy_math/src/geometry.rs

@@ -1,6 +1,6 @@
 use bevy_reflect::Reflect;
 use glam::Vec2;
-use std::ops::{Add, AddAssign};
+use std::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Sub, SubAssign};
 
 /// A two dimensional "size" as defined by a width and height
 #[derive(Copy, Clone, PartialEq, Debug, Reflect)]
@@ -81,3 +81,102 @@ where
         self.height += rhs.y;
     }
 }
+
+impl<T: Reflect> Sub<Vec2> for Size<T>
+where
+    T: Sub<f32, Output = T>,
+{
+    type Output = Size<T>;
+
+    fn sub(self, rhs: Vec2) -> Self::Output {
+        Self {
+            width: self.width - rhs.x,
+            height: self.height - rhs.y,
+        }
+    }
+}
+
+impl<T: Reflect> SubAssign<Vec2> for Size<T>
+where
+    T: SubAssign<f32>,
+{
+    fn sub_assign(&mut self, rhs: Vec2) {
+        self.width -= rhs.x;
+        self.height -= rhs.y;
+    }
+}
+
+impl<T: Reflect> Mul<f32> for Size<T>
+where
+    T: Mul<f32, Output = T>,
+{
+    type Output = Size<T>;
+
+    fn mul(self, rhs: f32) -> Self::Output {
+        Self::Output {
+            width: self.width * rhs,
+            height: self.height * rhs,
+        }
+    }
+}
+
+impl<T: Reflect> MulAssign<f32> for Size<T>
+where
+    T: MulAssign<f32>,
+{
+    fn mul_assign(&mut self, rhs: f32) {
+        self.width *= rhs;
+        self.height *= rhs;
+    }
+}
+
+impl<T: Reflect> Div<f32> for Size<T>
+where
+    T: Div<f32, Output = T>,
+{
+    type Output = Size<T>;
+
+    fn div(self, rhs: f32) -> Self::Output {
+        Self::Output {
+            width: self.width / rhs,
+            height: self.height / rhs,
+        }
+    }
+}
+
+impl<T: Reflect> DivAssign<f32> for Size<T>
+where
+    T: DivAssign<f32>,
+{
+    fn div_assign(&mut self, rhs: f32) {
+        self.width /= rhs;
+        self.height /= rhs;
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn size_ops() {
+        type SizeF = Size<f32>;
+
+        assert_eq!(
+            SizeF::new(10., 10.) + Vec2::new(10., 10.),
+            SizeF::new(20., 20.)
+        );
+        assert_eq!(
+            SizeF::new(20., 20.) - Vec2::new(10., 10.),
+            SizeF::new(10., 10.)
+        );
+        assert_eq!(SizeF::new(10., 10.) * 2., SizeF::new(20., 20.));
+        assert_eq!(SizeF::new(20., 20.) / 2., SizeF::new(10., 10.));
+
+        let mut size = SizeF::new(10., 10.);
+
+        size += Vec2::new(10., 10.);
+
+        assert_eq!(size, SizeF::new(20., 20.));
+    }
+}

crates/bevy_text/src/draw.rs

@@ -48,6 +48,7 @@ impl Default for TextStyle {
 pub struct DrawableText<'a> {
     pub render_resource_bindings: &'a mut RenderResourceBindings,
     pub position: Vec3,
+    pub scale_factor: f32,
     pub style: &'a TextStyle,
     pub text_glyphs: &'a Vec<PositionedGlyph>,
     pub msaa: &'a Msaa,
@@ -105,7 +106,20 @@ impl<'a> Drawable for DrawableText<'a> {
                 color: self.style.color,
             };
 
-            let transform = Mat4::from_translation(self.position + tv.position.extend(0.));
+            // To get the rendering right for non-one scaling factors, we need
+            // the sprite to be drawn in "physical" coordinates. This is because
+            // the shader uses the size of the sprite to control the size on
+            // screen. To accomplish this we make the sprite transform
+            // convert from physical coordinates to logical coordinates in
+            // addition to altering the origin. Since individual glyphs will
+            // already be in physical coordinates, we just need to convert the
+            // overall position to physical coordinates to get the sprites
+            // physical position.
+
+            let transform = Mat4::from_scale(Vec3::splat(1. / self.scale_factor))
+                * Mat4::from_translation(
+                    self.position * self.scale_factor + tv.position.extend(0.),
+                );
 
             let transform_buffer = context.get_uniform_buffer(&transform).unwrap();
             let sprite_buffer = context.get_uniform_buffer(&sprite).unwrap();

crates/bevy_text/src/text2d.rs

@@ -99,6 +99,7 @@ pub fn draw_text2d_system(
                 msaa: &msaa,
                 text_glyphs: &text_glyphs.glyphs,
                 font_quad_vertex_descriptor: &vertex_buffer_descriptor,
+                scale_factor: 1.,
                 style: &text.style,
             };
 
@@ -121,8 +122,8 @@ pub fn text2d_system(
     mut font_atlas_set_storage: ResMut<Assets<FontAtlasSet>>,
     mut text_pipeline: ResMut<DefaultTextPipeline>,
     mut text_queries: QuerySet<(
-        Query<Entity, Changed<Text>>,
-        Query<(&Text, &mut CalculatedSize)>,
+        Query<Entity, (With<MainPass>, Changed<Text>)>,
+        Query<(&Text, &mut CalculatedSize), With<MainPass>>,
     )>,
 ) {
     // Adds all entities where the text or the style has changed to the local queue

crates/bevy_ui/src/widget/text.rs

@@ -14,31 +14,38 @@ use bevy_text::{
     CalculatedSize, DefaultTextPipeline, DrawableText, Font, FontAtlasSet, Text, TextError,
 };
 use bevy_transform::prelude::GlobalTransform;
+use bevy_window::Windows;
 
 #[derive(Debug, Default)]
 pub struct QueuedText {
     entities: Vec<Entity>,
 }
 
+fn scale_value(value: f32, factor: f64) -> f32 {
+    (value as f64 * factor) as f32
+}
+
 /// 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 {
+pub fn text_constraint(min_size: Val, size: Val, max_size: Val, scale_factor: f64) -> 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,
+        (_, _, Val::Px(max)) => scale_value(max, scale_factor),
+        (Val::Px(min), _, _) => scale_value(min, scale_factor),
+        (Val::Undefined, Val::Px(size), Val::Undefined) => scale_value(size, scale_factor),
+        (Val::Auto, Val::Px(size), Val::Auto) => scale_value(size, scale_factor),
         _ => f32::MAX,
     }
 }
 
 /// Computes the size of a text block and updates the TextGlyphs with the
 /// new computed glyphs from the layout
+#[allow(clippy::too_many_arguments)]
 pub fn text_system(
     mut queued_text: Local<QueuedText>,
     mut textures: ResMut<Assets<Texture>>,
     fonts: Res<Assets<Font>>,
+    windows: Res<Windows>,
     mut texture_atlases: ResMut<Assets<TextureAtlas>>,
     mut font_atlas_set_storage: ResMut<Assets<FontAtlasSet>>,
     mut text_pipeline: ResMut<DefaultTextPipeline>,
@@ -47,6 +54,14 @@ pub fn text_system(
         Query<(&Text, &Style, &mut CalculatedSize)>,
     )>,
 ) {
+    let scale_factor = if let Some(window) = windows.get_primary() {
+        window.scale_factor()
+    } else {
+        1.
+    };
+
+    let inv_scale_factor = 1. / scale_factor;
+
     // Adds all entities where the text or the style has changed to the local queue
     for entity in text_queries.q0_mut().iter_mut() {
         queued_text.entities.push(entity);
@@ -62,11 +77,17 @@ pub fn text_system(
     for entity in queued_text.entities.drain(..) {
         if let Ok((text, style, mut calculated_size)) = query.get_mut(entity) {
             let node_size = Size::new(
-                text_constraint(style.min_size.width, style.size.width, style.max_size.width),
+                text_constraint(
+                    style.min_size.width,
+                    style.size.width,
+                    style.max_size.width,
+                    scale_factor,
+                ),
                 text_constraint(
                     style.min_size.height,
                     style.size.height,
                     style.max_size.height,
+                    scale_factor,
                 ),
             );
 
@@ -75,7 +96,7 @@ pub fn text_system(
                 text.font.clone(),
                 &fonts,
                 &text.value,
-                text.style.font_size,
+                scale_value(text.style.font_size, scale_factor),
                 text.style.alignment,
                 node_size,
                 &mut *font_atlas_set_storage,
@@ -93,7 +114,10 @@ pub fn text_system(
                     let text_layout_info = text_pipeline.get_glyphs(&entity).expect(
                         "Failed to get glyphs from the pipeline that have just been computed",
                     );
-                    calculated_size.size = text_layout_info.size;
+                    calculated_size.size = Size {
+                        width: scale_value(text_layout_info.size.width, inv_scale_factor),
+                        height: scale_value(text_layout_info.size.height, inv_scale_factor),
+                    };
                 }
             }
         }
@@ -106,11 +130,18 @@ pub fn text_system(
 pub fn draw_text_system(
     mut context: DrawContext,
     msaa: Res<Msaa>,
+    windows: Res<Windows>,
     meshes: Res<Assets<Mesh>>,
     mut render_resource_bindings: ResMut<RenderResourceBindings>,
     text_pipeline: Res<DefaultTextPipeline>,
     mut query: Query<(Entity, &mut Draw, &Visible, &Text, &Node, &GlobalTransform)>,
 ) {
+    let scale_factor = if let Some(window) = windows.get_primary() {
+        window.scale_factor()
+    } else {
+        1.
+    };
+
     let font_quad = meshes.get(&QUAD_HANDLE).unwrap();
     let vertex_buffer_descriptor = font_quad.get_vertex_buffer_descriptor();
 
@@ -125,6 +156,7 @@ pub fn draw_text_system(
             let mut drawable_text = DrawableText {
                 render_resource_bindings: &mut render_resource_bindings,
                 position,
+                scale_factor: scale_factor as f32,
                 msaa: &msaa,
                 text_glyphs: &text_glyphs.glyphs,
                 font_quad_vertex_descriptor: &vertex_buffer_descriptor,