Resolve a text draw's glyph origin once

core/src/ui/painter.rs

@@ -80,6 +80,21 @@ impl<'a> Painter<'a> {
 
     /// Takes the kind, for a caller writing many of one primitive.
     fn write<P: Primitive>(&mut self, kind: PrimitiveKind<P>, primitive: P, region: DrawRegion) {
+        self.write_resolved(
+            kind,
+            primitive,
+            region,
+            region.resolve(self.region, self.placement),
+        );
+    }
+
+    fn write_resolved<P: Primitive>(
+        &mut self,
+        kind: PrimitiveKind<P>,
+        primitive: P,
+        region: DrawRegion,
+        resolved: UiRegion,
+    ) {
         #[cfg(feature = "layout-diagnostics")]
         diag::bump(Counter::PrimitiveWrites);
         let h = self.state.layers.write(
@@ -88,7 +103,7 @@ impl<'a> Painter<'a> {
                 kind,
                 id: self.id,
                 primitive,
-                region: region.resolve(self.region, self.placement),
+                region: resolved,
                 mask_idx: self.mask,
                 move_idx: self.move_idx,
             },
@@ -404,9 +419,12 @@ impl<'a> Painter<'a> {
     // TODO: merge the text methods into the primitive ones.
     pub fn glyphs(&mut self, text: &RenderedText, origin: impl Into<DrawRegion>) {
         let origin = origin.into();
+        // Glyph offsets and sizes are pixels, which compose additively.
+        // Only the shared origin needs the frame/extent composition.
+        let resolved = origin.resolve(self.region, self.placement);
         let kind = self.rsc.ui_mut().primitives.kind::<GlyphPrimitive>();
         for glyph in text.glyphs.iter() {
-            let region = origin.map(|mut region| {
+            let place = |mut region: UiRegion| {
                 region.x.end = region.x.start;
                 region.y.end = region.y.start;
                 let mut region = region.offset(UiVec2::from_px(glyph.offset));
@@ -417,8 +435,8 @@ impl<'a> Painter<'a> {
                 region.x.end = region.x.start.offset(size.x);
                 region.y.end = region.y.start.offset(size.y);
                 region
-            });
-            self.write(
+            };
+            self.write_resolved(
                 kind,
                 GlyphPrimitive {
                     uv_min: glyph.entry.uv_min,
@@ -427,7 +445,8 @@ impl<'a> Painter<'a> {
                     color: text.color,
                     flags: glyph.entry.flags(),
                 },
-                region,
+                origin.map(place),
+                place(resolved),
             );
         }
     }