Move text layout and rendering to Parley

core/src/ui/painter.rs

@@ -1,7 +1,7 @@
 use crate::{
     Axis, Len, RenderedText, Size, SizeCtx, StrongWidget, TextAttrs, TextBuffer, TextData,
-    TextureHandle, UiRegion, UiRenderState, UiRsc, Widget, WidgetId,
-    render::{Mask, MaskIdx, Primitive, PrimitiveHandle, PrimitiveInst},
+    TextureHandle, UiRegion, UiRenderState, UiRsc, UiScalar, UiVec2, Widget, WidgetId,
+    render::{GlyphPrimitive, Mask, MaskIdx, Primitive, PrimitiveHandle, PrimitiveInst},
     util::Vec2,
 };
 
@@ -90,10 +90,44 @@ impl<'a> Painter<'a> {
         self.primitive_at(handle.primitive(), region);
     }
 
-    /// returns (handle, offset from top left)
-    pub fn render_text(&mut self, buffer: &mut TextBuffer, attrs: &TextAttrs) -> RenderedText {
+    pub fn render_text(
+        &mut self,
+        buffer: &mut TextBuffer,
+        attrs: &TextAttrs,
+        width: Option<f32>,
+    ) -> RenderedText {
         let ui = self.rsc.ui_mut();
-        ui.text.draw(buffer, attrs, &mut ui.textures)
+        ui.text.render(buffer, attrs, width, &mut ui.textures)
+    }
+
+    /// Draws one atlas-sampling quad per glyph.
+    pub fn glyphs(&mut self, text: &RenderedText, origin: UiRegion) {
+        let flags_for = |is_color| {
+            if is_color {
+                GlyphPrimitive::IS_COLOR
+            } else {
+                0
+            }
+        };
+        for glyph in text.glyphs.iter() {
+            let mut region = origin;
+            region.x.end = region.x.start;
+            region.y.end = region.y.start;
+            let mut region = region.offset(UiVec2::abs(glyph.offset));
+            region.x.end = region.x.start + UiScalar::abs(glyph.entry.width as f32);
+            region.y.end = region.y.start + UiScalar::abs(glyph.entry.height as f32);
+            self.primitive_at(
+                GlyphPrimitive {
+                    uv_min: glyph.entry.uv_min,
+                    uv_max: glyph.entry.uv_max,
+                    view_idx: glyph.entry.view_idx,
+                    sampler_idx: glyph.entry.sampler_idx,
+                    color: text.color,
+                    flags: flags_for(glyph.entry.is_color),
+                },
+                region,
+            );
+        }
     }
 
     pub fn region(&self) -> UiRegion {