[Impeller] Do not scale the miter limit applied to stroked text (#55745)

Fixes flutter/flutter#156224

Author: jason-simmons

impeller/display_list/aiks_dl_text_unittests.cc

@@ -32,6 +32,7 @@ namespace testing {
 struct TextRenderOptions {
   bool stroke = false;
   Scalar font_size = 50;
+  Scalar stroke_width = 1;
   DlColor color = DlColor::kYellow();
   SkPoint position = SkPoint::Make(100, 200);
   std::shared_ptr<DlMaskFilter> filter;
@@ -72,7 +73,7 @@ bool RenderTextInCanvasSkia(const std::shared_ptr<Context>& context,
   DlPaint text_paint;
   text_paint.setColor(options.color);
   text_paint.setMaskFilter(options.filter);
-  text_paint.setStrokeWidth(1);
+  text_paint.setStrokeWidth(options.stroke_width);
   text_paint.setDrawStyle(options.stroke ? DlDrawStyle::kStroke
                                          : DlDrawStyle::kFill);
   canvas.DrawTextFrame(frame, options.position.x(), options.position.y(),
@@ -159,6 +160,22 @@ TEST_P(AiksTest, CanRenderStrokedTextFrame) {
   ASSERT_TRUE(OpenPlaygroundHere(builder.Build()));
 }
 
+TEST_P(AiksTest, CanRenderTextStrokeWidth) {
+  DisplayListBuilder builder;
+
+  DlPaint paint;
+  paint.setColor(DlColor::ARGB(1, 0.1, 0.1, 0.1));
+  builder.DrawPaint(paint);
+
+  ASSERT_TRUE(RenderTextInCanvasSkia(GetContext(), builder, "LMNOP VWXYZ",
+                                     "Roboto-Medium.ttf",
+                                     {
+                                         .stroke = true,
+                                         .stroke_width = 4,
+                                     }));
+  ASSERT_TRUE(OpenPlaygroundHere(builder.Build()));
+}
+
 TEST_P(AiksTest, CanRenderTextFrameWithHalfScaling) {
   DisplayListBuilder builder;
 

impeller/fixtures/BUILD.gn

@@ -103,6 +103,7 @@ test_fixtures("file_fixtures") {
   fixtures = [
     "//flutter/third_party/txt/third_party/fonts/HomemadeApple.ttf",
     "//flutter/third_party/txt/third_party/fonts/NotoColorEmoji.ttf",
+    "//flutter/third_party/txt/third_party/fonts/Roboto-Medium.ttf",
     "//flutter/third_party/txt/third_party/fonts/Roboto-Regular.ttf",
     "airplane.jpg",
     "bay_bridge.jpg",

impeller/typographer/backends/skia/typographer_context_skia.cc

@@ -232,7 +232,7 @@ static void DrawGlyph(SkCanvas* canvas,
     glyph_paint.setStrokeWidth(prop->stroke_width * scaled_font.scale);
     glyph_paint.setStrokeCap(ToSkiaCap(prop->stroke_cap));
     glyph_paint.setStrokeJoin(ToSkiaJoin(prop->stroke_join));
-    glyph_paint.setStrokeMiter(prop->stroke_miter * scaled_font.scale);
+    glyph_paint.setStrokeMiter(prop->stroke_miter);
   }
   canvas->save();
   canvas->translate(glyph.subpixel_offset.x, glyph.subpixel_offset.y);
@@ -388,7 +388,7 @@ static Rect ComputeGlyphSize(const SkFont& font,
     glyph_paint.setStrokeWidth(glyph.properties->stroke_width * scale);
     glyph_paint.setStrokeCap(ToSkiaCap(glyph.properties->stroke_cap));
     glyph_paint.setStrokeJoin(ToSkiaJoin(glyph.properties->stroke_join));
-    glyph_paint.setStrokeMiter(glyph.properties->stroke_miter * scale);
+    glyph_paint.setStrokeMiter(glyph.properties->stroke_miter);
   }
   font.getBounds(&glyph.glyph.index, 1, &scaled_bounds, &glyph_paint);
 

testing/impeller_golden_tests_output.txt

@@ -466,6 +466,9 @@ impeller_Play_AiksTest_CanRenderTextInSaveLayer_Vulkan.png
 impeller_Play_AiksTest_CanRenderTextOutsideBoundaries_Metal.png
 impeller_Play_AiksTest_CanRenderTextOutsideBoundaries_OpenGLES.png
 impeller_Play_AiksTest_CanRenderTextOutsideBoundaries_Vulkan.png
+impeller_Play_AiksTest_CanRenderTextStrokeWidth_Metal.png
+impeller_Play_AiksTest_CanRenderTextStrokeWidth_OpenGLES.png
+impeller_Play_AiksTest_CanRenderTextStrokeWidth_Vulkan.png
 impeller_Play_AiksTest_CanRenderTextWithLargePerspectiveTransform_Metal.png
 impeller_Play_AiksTest_CanRenderTextWithLargePerspectiveTransform_OpenGLES.png
 impeller_Play_AiksTest_CanRenderTextWithLargePerspectiveTransform_Vulkan.png