Text snaps to pixel grid, images don't

Previously, we tried to use the render tree's paint offset to move the text to the proper position, but that appears to snap to integer logical pixels, introducing jitter. Now we use the SkCanvas's matrix to position the text, removing the jitter. Fixes flutter/flutter#234
abarth · Nov 20, 2015 · d12e614 · d12e614
1 parent 43f57d1
commit d12e614
Showing 1 changed file with 7 additions and 6 deletions.
diff --git a/sky/engine/core/text/Paragraph.cpp b/sky/engine/core/text/Paragraph.cpp
@@ -52,7 +52,7 @@ double Paragraph::ideographicBaseline()
 
 void Paragraph::layout()
 {
-    FontCachePurgePreventer fontCachePurgePreventer;
+    FontCachePurgePreventer fontCachePurgePreventer; 
 
     LayoutUnit maxWidth = std::max(m_minWidth, m_maxWidth);
     LayoutUnit maxHeight = std::max(m_minHeight, m_maxHeight);
@@ -66,18 +66,19 @@ void Paragraph::paint(Canvas* canvas, const Offset& offset)
 
     // Very simplified painting to allow painting an arbitrary (layer-less) subtree.
     RenderBox* box = firstChildBox();
-    GraphicsContext context(canvas->skCanvas());
+    SkCanvas* skCanvas = canvas->skCanvas();
+    skCanvas->translate(offset.sk_size.width(), offset.sk_size.height());
 
+    GraphicsContext context(skCanvas);
     Vector<RenderBox*> layers;
-    LayoutPoint paintOffset(offset.sk_size.width(), offset.sk_size.height());
     LayoutRect bounds = box->absoluteBoundingBoxRect();
     DCHECK(bounds.x() == 0 && bounds.y() == 0);
-    bounds.setLocation(paintOffset);
     PaintInfo paintInfo(&context, enclosingIntRect(bounds), box);
-    box->paint(paintInfo, paintOffset, layers);
-
+    box->paint(paintInfo, LayoutPoint(), layers);
     // Note we're ignoring any layers encountered.
     // TODO(abarth): Remove the concept of RenderLayers.
+
+    skCanvas->translate(-offset.sk_size.width(), -offset.sk_size.height());
 }
 
 } // namespace blink