When a bitmap is texture-backed, change SkBitmap::copyTo() to do a deep
copy of the texels in VRAM rather than a readback and re-upload.  This
gives a 3-10X speedup on recursive canvas-to-canvas draws.

N.B.:  This introduces a new GM test, which will need new baselines.



git-svn-id: http://skia.googlecode.com/svn/trunk@2790 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/bitmapcopy.cpp b/gm/bitmapcopy.cpp
new file mode 100644
index 0000000..249ec43
--- /dev/null
+++ b/gm/bitmapcopy.cpp
@@ -0,0 +1,121 @@
+
+/*
+ * Copyright 2011 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"
+
+namespace skiagm {
+
+static const char* gConfigNames[] = {
+    "unknown config",
+    "A1",
+    "A8",
+    "Index8",
+    "565",
+    "4444",
+    "8888"
+};
+
+SkBitmap::Config gConfigs[] = {
+  SkBitmap::kRGB_565_Config,
+  SkBitmap::kARGB_4444_Config,
+  SkBitmap::kARGB_8888_Config,
+};
+
+#define NUM_CONFIGS (sizeof(gConfigs) / sizeof(SkBitmap::Config))
+
+static void draw_checks(SkCanvas* canvas, int width, int height) {
+    SkPaint paint;
+    paint.setColor(SK_ColorRED);
+    canvas->drawRectCoords(0, 0, width / 2, height / 2, paint);
+    paint.setColor(SK_ColorGREEN);
+    canvas->drawRectCoords(width / 2, 0, width, height / 2, paint);
+    paint.setColor(SK_ColorBLUE);
+    canvas->drawRectCoords(0, height / 2, width / 2, height, paint);
+    paint.setColor(SK_ColorYELLOW);
+    canvas->drawRectCoords(width / 2, height / 2, width, height, paint);
+}
+
+class BitmapCopyGM : public GM {
+public:
+    SkBitmap    fDst[NUM_CONFIGS];
+
+    BitmapCopyGM() {
+        this->setBGColor(0xFFDDDDDD);
+    }
+
+protected:
+    virtual SkString onShortName() {
+        return SkString("bitmapcopy");
+    }
+
+    virtual SkISize onISize() {
+        return make_isize(540, 330);
+    }
+
+    virtual void onDraw(SkCanvas* canvas) {
+        SkPaint paint;
+        SkScalar horizMargin(SkIntToScalar(10));
+        SkScalar vertMargin(SkIntToScalar(10));
+
+        draw_checks(canvas, 40, 40);
+        SkBitmap src = canvas->getDevice()->accessBitmap(false);
+
+        for (unsigned i = 0; i < NUM_CONFIGS; ++i) {
+            if (!src.deepCopyTo(&fDst[i], gConfigs[i])) {
+                src.copyTo(&fDst[i], gConfigs[i]);
+            }
+        }
+
+        canvas->clear(0xFFDDDDDD);
+        paint.setAntiAlias(true);
+        SkScalar width = SkIntToScalar(40);
+        SkScalar height = SkIntToScalar(40);
+        if (paint.getFontSpacing() > height) {
+            height = paint.getFontSpacing();
+        }
+        for (unsigned i = 0; i < NUM_CONFIGS; i++) {
+            const char* name = gConfigNames[src.config()];
+            SkScalar textWidth = paint.measureText(name, strlen(name));
+            if (textWidth > width) {
+                width = textWidth;
+            }
+        }
+        SkScalar horizOffset = width + horizMargin;
+        SkScalar vertOffset = height + vertMargin;
+        canvas->translate(SkIntToScalar(20), SkIntToScalar(20));
+
+        for (unsigned i = 0; i < NUM_CONFIGS; i++) {
+            canvas->save();
+            // Draw destination config name
+            const char* name = gConfigNames[fDst[i].config()];
+            SkScalar textWidth = paint.measureText(name, strlen(name));
+            SkScalar x = (width - textWidth) / SkScalar(2);
+            SkScalar y = paint.getFontSpacing() / SkScalar(2);
+            canvas->drawText(name, strlen(name), x, y, paint);
+
+            // Draw destination bitmap
+            canvas->translate(0, vertOffset);
+            x = (width - 40) / SkScalar(2);
+            canvas->drawBitmap(fDst[i], x, 0, &paint);
+            canvas->restore();
+
+            canvas->translate(horizOffset, 0);
+        }
+    }
+
+    virtual uint32_t onGetFlags() const { return kSkipPicture_Flag; }
+
+private:
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static GM* MyFactory(void*) { return new BitmapCopyGM; }
+static GMRegistry reg(MyFactory);
+
+}