Rich text (bevyengine#1245)

Rich text support (different fonts / styles within the same text section)

crates/bevy_text/src/draw.rs

@@ -1,6 +1,5 @@
 use bevy_math::{Mat4, Vec3};
 use bevy_render::{
-    color::Color,
     draw::{Draw, DrawContext, DrawError, Drawable},
     mesh,
     mesh::Mesh,
@@ -9,47 +8,14 @@ use bevy_render::{
     renderer::{BindGroup, RenderResourceBindings, RenderResourceId},
 };
 use bevy_sprite::TextureAtlasSprite;
-use glyph_brush_layout::{HorizontalAlign, VerticalAlign};
 
-use crate::PositionedGlyph;
-
-#[derive(Debug, Clone, Copy)]
-pub struct TextAlignment {
-    pub vertical: VerticalAlign,
-    pub horizontal: HorizontalAlign,
-}
-
-impl Default for TextAlignment {
-    fn default() -> Self {
-        TextAlignment {
-            vertical: VerticalAlign::Top,
-            horizontal: HorizontalAlign::Left,
-        }
-    }
-}
-
-#[derive(Clone, Debug)]
-pub struct TextStyle {
-    pub font_size: f32,
-    pub color: Color,
-    pub alignment: TextAlignment,
-}
-
-impl Default for TextStyle {
-    fn default() -> Self {
-        Self {
-            color: Color::WHITE,
-            font_size: 12.0,
-            alignment: TextAlignment::default(),
-        }
-    }
-}
+use crate::{PositionedGlyph, TextSection};
 
 pub struct DrawableText<'a> {
     pub render_resource_bindings: &'a mut RenderResourceBindings,
     pub position: Vec3,
     pub scale_factor: f32,
-    pub style: &'a TextStyle,
+    pub sections: &'a [TextSection],
     pub text_glyphs: &'a Vec<PositionedGlyph>,
     pub msaa: &'a Msaa,
     pub font_quad_vertex_descriptor: &'a VertexBufferDescriptor,
@@ -103,7 +69,7 @@ impl<'a> Drawable for DrawableText<'a> {
 
             let sprite = TextureAtlasSprite {
                 index: tv.atlas_info.glyph_index,
-                color: self.style.color,
+                color: self.sections[tv.section_index].style.color,
             };
 
             // To get the rendering right for non-one scaling factors, we need

crates/bevy_text/src/glyph_brush.rs

@@ -4,7 +4,7 @@ use bevy_math::{Size, Vec2};
 use bevy_render::prelude::Texture;
 use bevy_sprite::TextureAtlas;
 use glyph_brush_layout::{
-    FontId, GlyphPositioner, Layout, SectionGeometry, SectionGlyph, ToSectionText,
+    FontId, GlyphPositioner, Layout, SectionGeometry, SectionGlyph, SectionText, ToSectionText,
 };
 
 use crate::{error::TextError, Font, FontAtlasSet, GlyphAtlasInfo, TextAlignment};
@@ -46,6 +46,7 @@ impl GlyphBrush {
     pub fn process_glyphs(
         &self,
         glyphs: Vec<SectionGlyph>,
+        sections: &[SectionText],
         font_atlas_set_storage: &mut Assets<FontAtlasSet>,
         fonts: &Assets<Font>,
         texture_atlases: &mut Assets<TextureAtlas>,
@@ -55,16 +56,26 @@ impl GlyphBrush {
             return Ok(Vec::new());
         }
 
-        let first_glyph = glyphs.first().expect("Must have at least one glyph.");
-        let font_id = first_glyph.font_id.0;
-        let handle = &self.handles[font_id];
-        let font = fonts.get(handle).ok_or(TextError::NoSuchFont)?;
-        let font_size = first_glyph.glyph.scale.y;
-        let scaled_font = ab_glyph::Font::as_scaled(&font.font, font_size);
+        let sections_data = sections
+            .iter()
+            .map(|section| {
+                let handle = &self.handles[section.font_id.0];
+                let font = fonts.get(handle).ok_or(TextError::NoSuchFont)?;
+                let font_size = section.scale.y;
+                Ok((
+                    handle,
+                    font,
+                    font_size,
+                    ab_glyph::Font::as_scaled(&font.font, font_size),
+                ))
+            })
+            .collect::<Result<Vec<_>, _>>()?;
+
         let mut max_y = std::f32::MIN;
         let mut min_x = std::f32::MAX;
-        for section_glyph in glyphs.iter() {
-            let glyph = &section_glyph.glyph;
+        for sg in glyphs.iter() {
+            let glyph = &sg.glyph;
+            let scaled_font = sections_data[sg.section_index].3;
             max_y = max_y.max(glyph.position.y - scaled_font.descent());
             min_x = min_x.min(glyph.position.x);
         }
@@ -82,14 +93,15 @@ impl GlyphBrush {
             let glyph_id = glyph.id;
             let glyph_position = glyph.position;
             let adjust = GlyphPlacementAdjuster::new(&mut glyph);
-            if let Some(outlined_glyph) = font.font.outline_glyph(glyph) {
+            let section_data = sections_data[sg.section_index];
+            if let Some(outlined_glyph) = section_data.1.font.outline_glyph(glyph) {
                 let bounds = outlined_glyph.px_bounds();
-                let handle_font_atlas: Handle<FontAtlasSet> = handle.as_weak();
+                let handle_font_atlas: Handle<FontAtlasSet> = section_data.0.as_weak();
                 let font_atlas_set = font_atlas_set_storage
                     .get_or_insert_with(handle_font_atlas, FontAtlasSet::default);
 
                 let atlas_info = font_atlas_set
-                    .get_glyph_atlas_info(font_size, glyph_id, glyph_position)
+                    .get_glyph_atlas_info(section_data.2, glyph_id, glyph_position)
                     .map(Ok)
                     .unwrap_or_else(|| {
                         font_atlas_set.add_glyph_to_atlas(texture_atlases, textures, outlined_glyph)
@@ -107,6 +119,7 @@ impl GlyphBrush {
                 positioned_glyphs.push(PositionedGlyph {
                     position,
                     atlas_info,
+                    section_index: sg.section_index,
                 });
             }
         }
@@ -126,6 +139,7 @@ impl GlyphBrush {
 pub struct PositionedGlyph {
     pub position: Vec2,
     pub atlas_info: GlyphAtlasInfo,
+    pub section_index: usize,
 }
 
 #[cfg(feature = "subpixel_glyph_atlas")]

crates/bevy_text/src/lib.rs

@@ -21,7 +21,7 @@ pub use text::*;
 pub use text2d::*;
 
 pub mod prelude {
-    pub use crate::{Font, Text, Text2dBundle, TextAlignment, TextError, TextStyle};
+    pub use crate::{Font, Text, Text2dBundle, TextAlignment, TextError, TextSection, TextStyle};
     pub use glyph_brush_layout::{HorizontalAlign, VerticalAlign};
 }
 

crates/bevy_text/src/pipeline.rs

@@ -10,7 +10,8 @@ use bevy_utils::HashMap;
 use glyph_brush_layout::{FontId, SectionText};
 
 use crate::{
-    error::TextError, glyph_brush::GlyphBrush, Font, FontAtlasSet, PositionedGlyph, TextAlignment,
+    error::TextError, glyph_brush::GlyphBrush, scale_value, Font, FontAtlasSet, PositionedGlyph,
+    TextAlignment, TextSection,
 };
 
 pub struct TextPipeline<ID> {
@@ -35,7 +36,7 @@ pub struct TextLayoutInfo {
 }
 
 impl<ID: Hash + Eq> TextPipeline<ID> {
-    pub fn get_or_insert_font_id(&mut self, handle: Handle<Font>, font: &Font) -> FontId {
+    pub fn get_or_insert_font_id(&mut self, handle: &Handle<Font>, font: &Font) -> FontId {
         let brush = &mut self.brush;
         *self
             .map_font_id
@@ -51,30 +52,40 @@ impl<ID: Hash + Eq> TextPipeline<ID> {
     pub fn queue_text(
         &mut self,
         id: ID,
-        font_handle: Handle<Font>,
         fonts: &Assets<Font>,
-        text: &str,
-        font_size: f32,
+        sections: &[TextSection],
+        scale_factor: f64,
         text_alignment: TextAlignment,
         bounds: Size,
         font_atlas_set_storage: &mut Assets<FontAtlasSet>,
         texture_atlases: &mut Assets<TextureAtlas>,
         textures: &mut Assets<Texture>,
     ) -> Result<(), TextError> {
-        let font = fonts.get(font_handle.id).ok_or(TextError::NoSuchFont)?;
-        let font_id = self.get_or_insert_font_id(font_handle, font);
-
-        let section = SectionText {
-            font_id,
-            scale: PxScale::from(font_size),
-            text,
-        };
-
-        let scaled_font = ab_glyph::Font::as_scaled(&font.font, font_size);
+        let mut scaled_fonts = Vec::new();
+        let sections = sections
+            .iter()
+            .map(|section| {
+                let font = fonts
+                    .get(section.style.font.id)
+                    .ok_or(TextError::NoSuchFont)?;
+                let font_id = self.get_or_insert_font_id(&section.style.font, font);
+                let font_size = scale_value(section.style.font_size, scale_factor);
+
+                scaled_fonts.push(ab_glyph::Font::as_scaled(&font.font, font_size));
+
+                let section = SectionText {
+                    font_id,
+                    scale: PxScale::from(font_size),
+                    text: &section.value,
+                };
+
+                Ok(section)
+            })
+            .collect::<Result<Vec<_>, _>>()?;
 
         let section_glyphs = self
             .brush
-            .compute_glyphs(&[section], bounds, text_alignment)?;
+            .compute_glyphs(&sections, bounds, text_alignment)?;
 
         if section_glyphs.is_empty() {
             self.glyph_map.insert(
@@ -92,8 +103,9 @@ impl<ID: Hash + Eq> TextPipeline<ID> {
         let mut max_x: f32 = std::f32::MIN;
         let mut max_y: f32 = std::f32::MIN;
 
-        for section_glyph in section_glyphs.iter() {
-            let glyph = &section_glyph.glyph;
+        for sg in section_glyphs.iter() {
+            let scaled_font = scaled_fonts[sg.section_index];
+            let glyph = &sg.glyph;
             min_x = min_x.min(glyph.position.x);
             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));
@@ -104,6 +116,7 @@ impl<ID: Hash + Eq> TextPipeline<ID> {
 
         let glyphs = self.brush.process_glyphs(
             section_glyphs,
+            &sections,
             font_atlas_set_storage,
             fonts,
             texture_atlases,

crates/bevy_text/src/text.rs

@@ -1,15 +1,106 @@
 use bevy_asset::Handle;
 use bevy_math::Size;
+use bevy_render::color::Color;
+use glyph_brush_layout::{HorizontalAlign, VerticalAlign};
 
-use crate::{Font, TextStyle};
+use crate::Font;
 
 #[derive(Debug, Default, Clone)]
 pub struct Text {
+    pub sections: Vec<TextSection>,
+    pub alignment: TextAlignment,
+}
+
+impl Text {
+    /// Constructs a [`Text`] with (initially) one section.
+    ///
+    /// ```
+    /// # use bevy_asset::{AssetServer, Handle};
+    /// # use bevy_render::color::Color;
+    /// # use bevy_text::{Font, Text, TextAlignment, TextStyle};
+    /// # use glyph_brush_layout::{HorizontalAlign, VerticalAlign};
+    /// #
+    /// # let font_handle: Handle<Font> = Default::default();
+    /// #
+    /// // basic usage
+    /// let hello_world = Text::with_section(
+    ///     "hello world!".to_string(),
+    ///     TextStyle {
+    ///         font: font_handle.clone(),
+    ///         font_size: 60.0,
+    ///         color: Color::WHITE,
+    ///     },
+    ///     TextAlignment {
+    ///         vertical: VerticalAlign::Center,
+    ///         horizontal: HorizontalAlign::Center,
+    ///     },
+    /// );
+    ///
+    /// let hello_bevy = Text::with_section(
+    ///     // accepts a String or any type that converts into a String, such as &str
+    ///     "hello bevy!",
+    ///     TextStyle {
+    ///         font: font_handle,
+    ///         font_size: 60.0,
+    ///         color: Color::WHITE,
+    ///     },
+    ///     // you can still use Default
+    ///     Default::default(),
+    /// );
+    /// ```
+    pub fn with_section<S: Into<String>>(
+        value: S,
+        style: TextStyle,
+        alignment: TextAlignment,
+    ) -> Self {
+        Self {
+            sections: vec![TextSection {
+                value: value.into(),
+                style,
+            }],
+            alignment,
+        }
+    }
+}
+
+#[derive(Debug, Default, Clone)]
+pub struct TextSection {
     pub value: String,
-    pub font: Handle<Font>,
     pub style: TextStyle,
 }
 
+#[derive(Debug, Clone, Copy)]
+pub struct TextAlignment {
+    pub vertical: VerticalAlign,
+    pub horizontal: HorizontalAlign,
+}
+
+impl Default for TextAlignment {
+    fn default() -> Self {
+        TextAlignment {
+            vertical: VerticalAlign::Top,
+            horizontal: HorizontalAlign::Left,
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct TextStyle {
+    pub font: Handle<Font>,
+    pub font_size: f32,
+    pub color: Color,
+}
+
+impl Default for TextStyle {
+    fn default() -> Self {
+        Self {
+            font: Default::default(),
+            font_size: 12.0,
+            color: Color::WHITE,
+        }
+    }
+}
+
 #[derive(Default, Copy, Clone, Debug)]
 pub struct CalculatedSize {
     pub size: Size,