[Impeller] fall back to path rendering on thick paths.

third_party/txt/src/skia/paragraph_skia.cc

@@ -22,6 +22,7 @@
 #include "fml/logging.h"
 #include "impeller/typographer/backends/skia/text_frame_skia.h"
 #include "include/core/SkMatrix.h"
+#include "third_party/skia/src/core/SkTextBlobPriv.h"  // nogncheck
 
 namespace txt {
 
@@ -85,6 +86,7 @@ class DisplayListParagraphPainter : public skt::ParagraphPainter {
 
 #ifdef IMPELLER_SUPPORTS_RENDERING
     if (impeller_enabled_) {
+      SkTextBlobRunIterator run(blob.get());
       if (ShouldRenderAsPath(dl_paints_[paint_id])) {
         auto path = skia::textlayout::Paragraph::GetPath(blob.get());
         // If there is no path, this is an emoji and should be drawn as is,
@@ -184,7 +186,14 @@ class DisplayListParagraphPainter : public skt::ParagraphPainter {
     // running on Impeller for correctness. These filters rely on having the
     // glyph coverage, whereas regular text is drawn as rectangular texture
     // samples.
-    return (paint.getColorSource() && !paint.getColorSource()->asColor());
+    // If the text is stroked and the stroke width is large enough, use path
+    // rendering anyway, as the fidelity problems won't be as noticable and
+    // rendering will be faster as it avoids software rasterization. A stroke
+    // width of four was chosen by eyeballing the point at which the path
+    // text looks good enough, with some room for error.
+    return (paint.getColorSource() && !paint.getColorSource()->asColor()) ||
+           (paint.getDrawStyle() == DlDrawStyle::kStroke &&
+            paint.getStrokeWidth() > 4);
   }
 
   DlPaint toDlPaint(const DecorationStyle& decor_style,

third_party/txt/tests/paragraph_unittests.cc

@@ -259,6 +259,23 @@ TEST_F(PainterTest, DrawStrokedTextImpeller) {
   EXPECT_EQ(recorder.pathCount(), 0);
 }
 
+TEST_F(PainterTest, DrawStrokedTextWithLargeWidthImpeller) {
+  PretendImpellerIsEnabled(true);
+
+  auto style = makeStyle();
+  DlPaint foreground;
+  foreground.setDrawStyle(DlDrawStyle::kStroke);
+  foreground.setStrokeWidth(10);
+  style.foreground = foreground;
+
+  auto recorder = DlOpRecorder();
+  draw(style)->Dispatch(recorder);
+
+  EXPECT_EQ(recorder.textFrameCount(), 0);
+  EXPECT_EQ(recorder.blobCount(), 0);
+  EXPECT_EQ(recorder.pathCount(), 1);
+}
+
 TEST_F(PainterTest, DrawTextWithGradientImpeller) {
   PretendImpellerIsEnabled(true);