Clean up textblobrandomfont.

The middle set of text is generated by rendering into a surface and
then blitting that to the canvas to generate a certain kind of text
generation. However, we are rendering with a -0.05 rotation and using
nearest-neighbor sampling, which produces nasty artifacts unrelated to
text. Changed the sample to render into the surface with the rotation,
and blit back with no rotation.

Bug: skia:7115
Change-Id: Iac1338f556cacc6c617ca14a625c649a6e7b9a48
Reviewed-on: https://skia-review.googlesource.com/130027
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>

1 files changed, 29 insertions, 23 deletions

diff --git a/gm/textblobrandomfont.cpp b/gm/textblobrandomfont.cpp
index 4aad888dbc..acde46887d 100644
--- a/gm/textblobrandomfont.cpp
+++ b/gm/textblobrandomfont.cpp
@@ -120,33 +120,39 @@ protected:
         SkPaint paint;
         paint.setAntiAlias(true);
 
-        SkCanvas* c = surface->getCanvas();
+        SkCanvas* surfaceCanvas = surface->getCanvas();
 
         SkScalar stride = SkScalarCeilToScalar(fBlob->bounds().height());
         SkScalar yOffset = 5;
-        for (int i = 0; i < 1; i++) {
-            // fiddle the canvas to force regen of textblobs
-            canvas->rotate(i % 2 ? 0.0f : -0.05f);
-
-            canvas->drawTextBlob(fBlob, 10, yOffset, paint);
-            yOffset += stride;
-
-            // this will test lcd masks when not requested
-            // on cpu this currently causes unspecified behavior, so avoid until it is fixed
-            if (canvas->getGrContext()) {
-                c->drawTextBlob(fBlob, 10, yOffset, paint);
-                surface->draw(canvas, 0, 0, nullptr);
-            }
-            yOffset += stride;
-
-            // free gpu resources and verify
-            if (canvas->getGrContext()) {
-                canvas->getGrContext()->freeGpuResources();
-            }
-
-            canvas->drawTextBlob(fBlob, 10, yOffset, paint);
-            yOffset += stride;
+
+        canvas->save();
+        // Originally we would alternate between rotating and not to force blob regeneration,
+        // but that code seems to have rotted. Keeping the rotate to match the old GM as
+        // much as possible, and it seems like a reasonable stress test for transformed
+        // color emoji.
+        canvas->rotate(-0.05f);
+        canvas->drawTextBlob(fBlob, 10, yOffset, paint);
+        yOffset += stride;
+        canvas->restore();
+
+        // this will test lcd masks when not requested
+        // on cpu this currently causes unspecified behavior, so avoid until it is fixed
+        if (canvas->getGrContext()) {
+            // Rotate in the surface canvas, not the final canvas, to avoid aliasing
+            surfaceCanvas->rotate(-0.05f);
+            surfaceCanvas->drawTextBlob(fBlob, 10, yOffset, paint);
+            surface->draw(canvas, 0, 0, nullptr);
+        }
+        yOffset += stride;
+
+        // free gpu resources and verify
+        if (canvas->getGrContext()) {
+            canvas->getGrContext()->freeGpuResources();
         }
+
+        canvas->rotate(-0.05f);
+        canvas->drawTextBlob(fBlob, 10, yOffset, paint);
+        yOffset += stride;
     }
 
 private: