fix for cached textblobs look garbled

gm/textblobgeometrychange.cpp

Index: gm/textblobgeometrychange.cpp
diff --git a/gm/textblobgeometrychange.cpp b/gm/textblobgeometrychange.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..eecad892fe027699561396b679de6c7a040a534b
--- /dev/null
+++ b/gm/textblobgeometrychange.cpp
@@ -0,0 +1,87 @@
+/*

[robertphillips, 2015/05/11 18:34:41]

timewarp

[joshualitt, 2015/05/11 19:07:47]

Acknowledged.

+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "gm.h"
+
+#include "Resources.h"
+#include "SkCanvas.h"

[robertphillips, 2015/05/11 18:34:41]

Do we need gradient shader ?

[joshualitt, 2015/05/11 19:07:47]

Acknowledged.

+#include "SkGradientShader.h"
+#include "SkStream.h"
+#include "SkSurface.h"
+#include "SkTextBlob.h"
+#include "SkTypeface.h"
+
+namespace skiagm {

[robertphillips, 2015/05/11 18:34:41]

// informative comment ?
// link to Chrome bug ?

[joshualitt, 2015/05/11 19:07:47]

Acknowledged.

+class TextBlobGeometryChange : public GM {
+public:
+    TextBlobGeometryChange() { }
+
+protected:

[robertphillips, 2015/05/11 18:34:41]

rm this ?

[joshualitt, 2015/05/11 19:07:47]

Acknowledged.

+    void onOnceBeforeDraw() override {
+    }
+
+    SkString onShortName() override {
+        return SkString("textblobgeometrychange");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(kWidth, kHeight);
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+        SkPaint paint;
+
+        canvas->clear(0x00ffffff);

[bsalomon, 2015/05/11 18:33:13]

Do we really want the bad looking LCD text on transparent? Also, transparent GMs
cause headaches for baselining since the background of the baselining UI is
composited in.

[joshualitt, 2015/05/11 19:07:47]

Acknowledged.

+

[robertphillips, 2015/05/11 18:34:41]

Maybe a build_lcd_blob helper ?

[joshualitt, 2015/05/11 19:07:47]

Acknowledged.

+        const char text[] = "Hamburgefons";
+        SkTDArray<uint16_t> glyphs;
+        size_t len = strlen(text);
+        glyphs.append(paint.textToGlyphs(text, len, NULL));
+        paint.textToGlyphs(text, len, glyphs.begin());
+        paint.setTextSize(20);
+        paint.setAntiAlias(true);
+        paint.setLCDRenderText(true);
+
+        SkTextBlobBuilder builder;
+
+        paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);

[robertphillips, 2015/05/11 18:34:41]

overlength 

[joshualitt, 2015/05/11 19:07:47]

Acknowledged.

+        const SkTextBlobBuilder::RunBuffer& run = builder.allocRun(paint, glyphs.count(), 10, 10, NULL);

[bsalomon, 2015/05/11 18:33:13]

wrap?

[joshualitt, 2015/05/11 19:07:47]

Acknowledged.

+        memcpy(run.glyphs, glyphs.begin(), glyphs.count() * sizeof(uint16_t));
+
+        SkAutoTUnref<const SkTextBlob> blob(builder.build());
+
+        SkImageInfo info = SkImageInfo::MakeN32Premul(200, 200);
+        SkSurfaceProps props(0, kUnknown_SkPixelGeometry);
+        SkAutoTUnref<SkSurface> surface(canvas->newSurface(info, &props));
+        SkCanvas* c = surface->getCanvas();
+
+        // LCD text on white background
+        SkRect rect = SkRect::MakeLTRB(0, 0, kWidth, kHeight / 2);
+        SkPaint rectPaint;
+        rectPaint.setColor(0xffffffff);
+        canvas->drawRect(rect, rectPaint);
+        canvas->drawTextBlob(blob.get(), 10, 50, paint);
+
+        // This should not look garbled
+        rect = SkRect::MakeLTRB(0, kHeight / 2, kWidth, kHeight);
+        rectPaint.setColor(0x00ffffff);
+        c->drawRect(rect, rectPaint);
+        c->drawTextBlob(blob.get(), 10, 150, paint);
+        surface->draw(canvas, 0, 0, nullptr);
+    }
+
+private:
+    static const int kWidth = 200;
+    static const int kHeight = 200;
+
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+DEF_GM( return SkNEW(TextBlobGeometryChange); )
+}