Add new GM to targeted at rect->clear optimization with different xfermodes.

gm/xfermodes3.cpp

Index: gm/xfermodes3.cpp
diff --git a/gm/xfermodes3.cpp b/gm/xfermodes3.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..a4fdcd5dfa75065fd48770c6d586094a1b631f9b
--- /dev/null
+++ b/gm/xfermodes3.cpp
@@ -0,0 +1,236 @@
+
+/*
+ * 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 "SkBitmap.h"
+#include "SkGradientShader.h"
+#include "SkXfermode.h"
+#include "SkColorPriv.h"
+
+#if SK_SUPPORT_GPU
+#include "GrContext.h"
+#include "SkGpuDevice.h"
+#endif
+
+namespace skiagm {
+
+/**
+ * This tests drawing device-covering rects with solid colors and bitmap shaders over a
+ * checkerboard background using different xfermodes.
+ */
+class Xfermodes3GM : public GM {
+public:
+    Xfermodes3GM() {}
+
+protected:
+    virtual SkString onShortName() SK_OVERRIDE {
+        return SkString("xfermodes3");
+    }
+
+    virtual SkISize onISize() SK_OVERRIDE {
+        return make_isize(630, 620);
+    }
+
+    virtual void onDrawBackground(SkCanvas* canvas) SK_OVERRIDE {
+        SkPaint bgPaint;
+        bgPaint.setColor(0xFF70D0E0);
+        canvas->drawPaint(bgPaint);
+    }
+
+    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+        canvas->translate(SkIntToScalar(10), SkIntToScalar(20));
+
+        SkPaint labelP;
+        labelP.setAntiAlias(true);
+
+        static const SkColor kSolidColors[] = {
+            SK_ColorTRANSPARENT,
+            SK_ColorBLUE,
+            0x80808000
+        };
+
+        static const SkColor kBmpAlphas[] = {
+            0xff,
+            0x80,
+        };
+
+        SkAutoTUnref<SkCanvas> tempCanvas(this->possiblyCreateTempCanvas(canvas, kSize, kSize));
+
+        int test = 0;
+        int x = 0, y = 0;

[robertphillips, 2013/08/07 23:16:14]

++m

[bsalomon, 2013/08/08 21:00:37]

Done.

+        for (size_t m = 0; m <= SkXfermode::kLastMode; m++) {
+            SkXfermode::Mode mode = static_cast<SkXfermode::Mode>(m);
+            canvas->drawText(SkXfermode::ModeName(mode),
+                             strlen(SkXfermode::ModeName(mode)),
+                             SkIntToScalar(x),
+                             SkIntToScalar(y + kSize + 3) + labelP.getTextSize(),
+                             labelP);
+            for (size_t c = 0; c < SK_ARRAY_COUNT(kSolidColors); ++c) {
+                SkPaint modePaint;
+                modePaint.setXfermodeMode(mode);
+                modePaint.setColor(kSolidColors[c]);
+
+                this->drawMode(canvas, x, y, kSize, kSize, modePaint, tempCanvas.get());
+
+                ++test;
+                x += kSize + 10;
+                if (!(test % kTestsPerRow)) {
+                    x = 0;
+                    y += kSize + 30;
+                }
+            }
+            for (size_t a = 0; a < SK_ARRAY_COUNT(kBmpAlphas); ++a) {
+                SkPaint modePaint;
+                modePaint.setXfermodeMode(mode);
+                modePaint.setAlpha(kBmpAlphas[a]);
+                modePaint.setShader(fBmpShader);
+
+                this->drawMode(canvas, x, y, kSize, kSize, modePaint, tempCanvas.get());
+
+                ++test;
+                x += kSize + 10;
+                if (!(test % kTestsPerRow)) {
+                    x = 0;
+                    y += kSize + 30;
+                }
+            }
+        }
+    }
+
+private:
+    /**
+     * GrContext has optimizations around full rendertarget draws that can be replaced with clears.
+     * We are trying to test those. We could use saveLayer() to create small SkGpuDevices but
+     * saveLayer() uses the texture cache. This means that the actual render target may be larger
+     * than the layer. Because the clip will contain the layer's bounds, no draws will be full-RT.
+     * So when running on a GPU canvas we explicitly create a temporary canvas using a texture with
+     * dimensions exactly matching the layer size.
+     */
+    SkCanvas* possiblyCreateTempCanvas(SkCanvas* baseCanvas, int w, int h) {
+        SkCanvas* tempCanvas = NULL;
+#if SK_SUPPORT_GPU
+        GrRenderTarget* rt = baseCanvas->getDevice()->accessRenderTarget();
+        if (NULL != rt) {
+            GrContext* context = rt->getContext();
+            GrTextureDesc desc;
+            desc.fWidth = w;
+            desc.fHeight = h;
+            desc.fConfig = rt->config();
+            desc.fFlags = kRenderTarget_GrTextureFlagBit;
+            SkAutoTUnref<GrSurface> surface(context->createUncachedTexture(desc, NULL, 0));
+            SkAutoTUnref<SkDevice> device(SkGpuDevice::Create(surface.get()));
+            if (NULL != device.get()) {
+                tempCanvas = SkNEW_ARGS(SkCanvas, (device.get()));
+            }
+        }
+#endif
+        return tempCanvas;
+    }
+
+    void drawMode(SkCanvas* canvas,
+                  int x, int y, int w, int h,

[robertphillips, 2013/08/07 23:16:14]

const SkPaint& ?

[bsalomon, 2013/08/08 21:00:37]

Done.

+                  SkPaint& modePaint, SkCanvas* layerCanvas) {
+        canvas->save();
+
+        canvas->translate(SkIntToScalar(x), SkIntToScalar(y));
+
+        SkRect r = SkRect::MakeWH(SkIntToScalar(w), SkIntToScalar(h));
+
+        SkCanvas* modeCanvas;
+        if (NULL == layerCanvas) {
+            canvas->saveLayer(&r, NULL, SkCanvas::kARGB_ClipLayer_SaveFlag);
+            modeCanvas = canvas;
+        } else {
+            modeCanvas = layerCanvas;
+        }
+
+        SkPaint bgPaint;
+        bgPaint.setAntiAlias(false);
+        bgPaint.setShader(fBG);
+        modeCanvas->drawRect(r, bgPaint);
+        modeCanvas->drawRect(r, modePaint);
+        modeCanvas = NULL;
+
+        if (NULL == layerCanvas) {
+            canvas->restore();
+        } else {
+            SkBitmap bitmap = layerCanvas->getDevice()->accessBitmap(false);
+            canvas->drawBitmap(bitmap, 0, 0);
+        }
+
+        r.inset(-SK_ScalarHalf, -SK_ScalarHalf);
+        SkPaint borderPaint;
+        borderPaint.setStyle(SkPaint::kStroke_Style);
+        canvas->drawRect(r, borderPaint);
+
+        canvas->restore();
+    }
+
+    virtual void onOnceBeforeDraw() SK_OVERRIDE {
+        static const uint32_t kCheckData[] = {
+            SkPackARGB32(0xFF, 0x40, 0x40, 0x40),
+            SkPackARGB32(0xFF, 0xD0, 0xD0, 0xD0),
+            SkPackARGB32(0xFF, 0xD0, 0xD0, 0xD0),
+            SkPackARGB32(0xFF, 0x40, 0x40, 0x40)
+        };
+        SkBitmap bg;
+        bg.setConfig(SkBitmap::kARGB_8888_Config, 2, 2);
+        bg.allocPixels();
+        SkAutoLockPixels bgAlp(bg);
+        memcpy(bg.getPixels(), kCheckData, sizeof(kCheckData));
+        bg.setIsOpaque(true);
+
+        fBG.reset(SkShader::CreateBitmapShader(bg,
+                                               SkShader::kRepeat_TileMode,
+                                               SkShader::kRepeat_TileMode));
+        SkMatrix lm;
+        lm.setScale(SkIntToScalar(kCheckSize), SkIntToScalar(kCheckSize));
+        fBG->setLocalMatrix(lm);
+
+        SkBitmap bmp;
+        bmp.setConfig(SkBitmap::kARGB_8888_Config, kSize, kSize);
+        bmp.allocPixels();
+
+        SkPaint bmpPaint;
+        static const SkPoint kCenter = { SkIntToScalar(kSize) / 2, SkIntToScalar(kSize) / 2 };
+        static const SkColor kColors[] = { SK_ColorTRANSPARENT, 0x80800000,
+                                          0xF020F060, SK_ColorWHITE };
+        bmpPaint.setShader(SkGradientShader::CreateRadial(kCenter,
+                                                          3 * SkIntToScalar(kSize) / 4,
+                                                          kColors,
+                                                          NULL,
+                                                          SK_ARRAY_COUNT(kColors),
+                                                          SkShader::kRepeat_TileMode))->unref();

[robertphillips, 2013/08/07 23:16:14]

Move creation & alloc of bmp to right before use in bmpCanvas?

[bsalomon, 2013/08/08 21:00:37]

Done.

+        SkCanvas bmpCanvas(bmp);
+        bmpCanvas.clear(SK_ColorTRANSPARENT);
+        SkRect rect = { SkIntToScalar(kSize) / 8, SkIntToScalar(kSize) / 8,
+                        7 * SkIntToScalar(kSize) / 8, 7 * SkIntToScalar(kSize) / 8};
+        bmpCanvas.drawRect(rect, bmpPaint);
+

[robertphillips, 2013/08/07 23:16:14]

Is there a better name then fBmpShader? fGradShader?

[bsalomon, 2013/08/08 21:00:37]

It is a bmp shader. I'm testing drawing a screen filling bitmap (with
transparency). The gradient just exists to put some content in the bitmap, it
could be anything.

+        fBmpShader.reset(SkShader::CreateBitmapShader(bmp,
+                                                      SkShader::kClamp_TileMode,
+                                                      SkShader::kClamp_TileMode));
+    }
+
+    enum {
+        kCheckSize = 8,
+        kSize = 30,
+        kTestsPerRow = 15,
+    };
+

[robertphillips, 2013/08/07 23:16:14]

fBGShader?

[bsalomon, 2013/08/08 21:00:37]

Done.

+    SkAutoTUnref<SkShader> fBG;
+    SkAutoTUnref<SkShader> fBmpShader;
+
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+

[robertphillips, 2013/08/07 23:16:14]

DEF_GM?

+static GM* MyFactory(void*) { return new Xfermodes3GM; }
+static GMRegistry reg(MyFactory);
+
+}