adding gm to use random scaler context

gm/textblobrandomfont.cpp

Index: gm/textblobrandomfont.cpp
diff --git a/gm/textblobrandomfont.cpp b/gm/textblobrandomfont.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..f7d3b5cb1c318a19ebaac1557486d220983dd78b
--- /dev/null
+++ b/gm/textblobrandomfont.cpp
@@ -0,0 +1,132 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "gm.h"
+
+#include "Resources.h"
+#include "SkCanvas.h"
+#include "SkGradientShader.h"
+#include "SkStream.h"
+#include "SkSurface.h"
+#include "SkTextBlob.h"
+#include "SkTypeface.h"
+#include "../src/fonts/SkRandomScalerContext.h"
+
+#if SK_SUPPORT_GPU
+
+#include "GrContext.h"
+
+namespace skiagm {
+class TextBlobRandomFont : public GM {
+public:
+    // This gm tests that textblobs can be translated and scaled with a font that returns random
+    // but deterministic masks
+    TextBlobRandomFont() { }
+
+protected:
+    void onOnceBeforeDraw() override {
+        SkTextBlobBuilder builder;
+
+        const char* text = "The quick brown fox jumps over the lazy dog.";
+
+        // make textbloben
+        SkPaint paint;
+        paint.setTextSize(32);
+        paint.setLCDRenderText(true);
+
+        // Setup our random scaler context
+        SkAutoTUnref<SkTypeface> orig(sk_tool_utils::create_portable_typeface("sans-serif",
+                                                                              SkTypeface::kBold));
+        if (NULL == orig) {
+            orig.reset(SkTypeface::RefDefault());
+        }
+        SkAutoTUnref<SkTypeface> random(SkNEW_ARGS(SkRandomTypeface, (orig, paint, false)));
+        paint.setTypeface(random);
+
+        SkRect bounds;
+        paint.measureText(text, strlen(text), &bounds);
+
+        SkScalar yOffset = bounds.height();
+        sk_tool_utils::add_to_text_blob(&builder, text, paint, 0, 0);
+
+        // A8
+        paint.setSubpixelText(false);
+        paint.setLCDRenderText(false);
+        sk_tool_utils::add_to_text_blob(&builder, text, paint, 0, yOffset - 32);
+
+        // build
+        fBlob.reset(builder.build());
+    }
+
+    SkString onShortName() override {
+        return SkString("textblobrandomfont");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(kWidth, kHeight);
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+        // This GM exists to test a specific feature of the GPU backend.
+        if (NULL == canvas->getGrContext()) {
+            this->drawGpuOnlyMessage(canvas);
+            return;
+        }
+
+        canvas->drawColor(sk_tool_utils::color_to_565(SK_ColorWHITE));
+
+        SkImageInfo info = SkImageInfo::MakeN32Premul(kWidth, kHeight);
+        SkSurfaceProps props(0, kUnknown_SkPixelGeometry);
+        SkAutoTUnref<SkSurface> surface(canvas->newSurface(info, &props));
+        if (surface) {
+            SkPaint paint;
+            paint.setAntiAlias(true);
+
+            SkCanvas* c = surface->getCanvas();
+
+            int stride = SkScalarCeilToInt(fBlob->bounds().height() / 2) + 10;
+            int yOffset = stride;
+            for (int i = 0; i < 10; i++) {
+                // fiddle the canvas to force regen of textblobs
+                canvas->rotate(i % 2 ? 0.0f : -0.05f);
+                canvas->drawTextBlob(fBlob, 10.0f, SkIntToScalar(yOffset), paint);
+                yOffset += stride;
+
+                // This will draw as black boxes
+                c->drawTextBlob(fBlob, 10, SkIntToScalar(yOffset), paint);
+                surface->draw(canvas, 0, 0, nullptr);
+
+                // free gpu resources and verify
+                yOffset += stride;
+                canvas->getGrContext()->freeGpuResources();
+                canvas->drawTextBlob(fBlob, 10, SkIntToScalar(yOffset), paint);
+
+                yOffset += stride;
+            }
+
+        } else {
+            const char* text = "This test requires a surface";
+            size_t len = strlen(text);
+            SkPaint paint;
+            canvas->drawText(text, len, 10, 100, paint);
+        }
+    }
+
+private:
+    SkAutoTUnref<const SkTextBlob> fBlob;
+
+    static const int kWidth = 1000;
+    static const int kHeight = 1000;
+
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+DEF_GM( return SkNEW(TextBlobRandomFont); )
+}
+#endif