Added GM to test forthcoming bleed flag

gm/bleed.cpp

Index: gm/bleed.cpp
===================================================================
--- gm/bleed.cpp	(revision 0)
+++ gm/bleed.cpp	(revision 0)
@@ -0,0 +1,170 @@
+/*
+ * Copyright 2013 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 "SkCanvas.h"
+
+#if SK_SUPPORT_GPU
+#include "GrContext.h"
+
+namespace skiagm {
+extern GrContext* GetGr();
+};
+
+void GrContext::setMaxTextureSizeOverride(int maxTextureSizeOverride) {
+    fMaxTextureSizeOverride = maxTextureSizeOverride;
+}
+#endif
+
+// Create a black&white checked texture with a 1-pixel red ring 
+// around the outside edge
+static void make_red_ringed_bitmap(SkBitmap* result, int width, int height) {
+    SkASSERT(0 == width % 2 && 0 == width % 2);
+
+    result->setConfig(SkBitmap::kARGB_8888_Config, width, height);
+    result->allocPixels();
+    SkAutoLockPixels lock(*result);
+
+    SkPMColor* scanline = result->getAddr32(0, 0);    
+    for (int x = 0; x < width; ++x) {
+        scanline[x] = SK_ColorRED;
+    }
+
+    for (int y = 1; y < height/2; ++y) {
+        scanline = result->getAddr32(0, y);
+        scanline[0] = SK_ColorRED;
+        for (int x = 1; x < width/2; ++x) {
+            scanline[x] = SK_ColorBLACK;
+        }
+        for (int x = width/2; x < width-1; ++x) {
+            scanline[x] = SK_ColorWHITE;
+        }
+        scanline[width-1] = SK_ColorRED;
+    }
+
+    for (int y = height/2; y < height-1; ++y) {
+        scanline = result->getAddr32(0, y);
+        scanline[0] = SK_ColorRED;
+        for (int x = 1; x < width/2; ++x) {
+            scanline[x] = SK_ColorWHITE;
+        }
+        for (int x = width/2; x < width-1; ++x) {
+            scanline[x] = SK_ColorBLACK;
+        }
+        scanline[width-1] = SK_ColorRED;
+    }
+
+    scanline = result->getAddr32(0, height-1);
+    for (int x = 0; x < width; ++x) {
+        scanline[x] = SK_ColorRED;
+    }
+    result->setIsOpaque(true);
+    result->setImmutable();
+}
+
+// This GM exercises the drawBitmapRectToRect "bleed" flag
+class BleedGM : public skiagm::GM {
+public:
+    BleedGM() {}
+
+protected:
+    virtual SkString onShortName() SK_OVERRIDE {
+        return SkString("bleed");
+    }
+
+    virtual SkISize onISize() SK_OVERRIDE {
+        return SkISize::Make(kWidth, kHeight);
+    }
+
+    virtual void onOnceBeforeDraw() SK_OVERRIDE {
+        make_red_ringed_bitmap(&fBitmapSmall, kSmallTextureSize, kSmallTextureSize);
+
+        // To exercise the GPU's tiling path we need a texture
+        // too big for the GPU to handle in one go
+        make_red_ringed_bitmap(&fBitmapBig, 2*kMaxTextureSize, 2*kMaxTextureSize);
+    }
+
+    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+#if SK_SUPPORT_GPU
+        GrContext* ctx = skiagm::GetGr();
+        int oldMaxTextureSize = 0;
+        if (NULL != ctx) {
+            // shrink the max texture size so all our textures can be reasonably sized
+            oldMaxTextureSize = ctx->getMaxTextureSize();
+            ctx->setMaxTextureSizeOverride(kMaxTextureSize);
+        }        
+#endif
+        
+        canvas->clear(SK_ColorGRAY);
+
+        SkPaint paint;
+
+        // Bleeding only comes into play when filtering
+        paint.setFilterBitmap(true);
+
+        // carve out the center of the small bitmap
+        SkRect src = SkRect::MakeXYWH(1, 1, 
+                                      kSmallTextureSize-2, 
+                                      kSmallTextureSize-2);
+        SkRect dst = SkRect::MakeXYWH(10, 10, 100, 100);
+
+        // first draw without bleeding
+        canvas->drawBitmapRectToRect(fBitmapSmall, &src, dst, &paint);
+
+        // then draw with bleeding
+        dst = SkRect::MakeXYWH(120, 10, 100, 100);
+        canvas->drawBitmapRectToRect(fBitmapSmall, &src, dst, &paint);
+
+        // Next test out the GPU's tiling of large textures
+
+        // first draw almost the whole thing
+        src = SkRect::MakeXYWH(1, 1, 
+                               SkIntToScalar(fBitmapBig.width()-2), 
+                               SkIntToScalar(fBitmapBig.height()-2));
+        dst = SkRect::MakeXYWH(10, 120, 100, 100);
+
+        // first without bleeding
+        canvas->drawBitmapRectToRect(fBitmapBig, &src, dst, &paint);
+
+        // then with bleeding
+        dst = SkRect::MakeXYWH(120, 120, 100, 100);
+        canvas->drawBitmapRectToRect(fBitmapBig, &src, dst, &paint);
+
+        // next draw ~1/4 of the bitmap
+        src = SkRect::MakeXYWH(1, 1, 
+                               SkIntToScalar(fBitmapBig.width()/2-1), 
+                               SkIntToScalar(fBitmapBig.height()/2-1));
+        dst = SkRect::MakeXYWH(10, 230, 100, 100);
+
+        // first without bleeding
+        canvas->drawBitmapRectToRect(fBitmapBig, &src, dst, &paint);
+
+        // then with bleeding
+        dst = SkRect::MakeXYWH(120, 230, 100, 100);
+        canvas->drawBitmapRectToRect(fBitmapBig, &src, dst, &paint);
+
+#if SK_SUPPORT_GPU
+        if (NULL != ctx) {
+            ctx->setMaxTextureSizeOverride(oldMaxTextureSize);
+        }        
+#endif
+    }
+
+private:
+    static const int kWidth = 230;
+    static const int kHeight = 340;
+
+    static const int kSmallTextureSize = 4;
+    static const int kMaxTextureSize = 32;
+
+    SkBitmap fBitmapSmall;
+    SkBitmap fBitmapBig;
+
+    typedef GM INHERITED;
+};
+
+DEF_GM( return new BleedGM(); )