add gm for image->newShader

src/utils/SkImageGeneratorUtils.cpp

Index: src/utils/SkImageGeneratorUtils.cpp
diff --git a/src/utils/SkImageGeneratorUtils.cpp b/src/utils/SkImageGeneratorUtils.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..f5198c05feb8a02186a81394f1d0b54720ef3dfe
--- /dev/null
+++ b/src/utils/SkImageGeneratorUtils.cpp
@@ -0,0 +1,134 @@
+/*
+ * 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 "SkImageGeneratorUtils.h"
+#include "SkBitmap.h"
+
+class GeneratorFromEmpty : public SkImageGenerator {
+public:
+    GeneratorFromEmpty(const SkImageInfo& info) : SkImageGenerator(info) {}
+};
+
+SkImageGenerator* SkImageGeneratorUtils::NewEmpty(const SkImageInfo& info) {
+    return SkNEW_ARGS(GeneratorFromEmpty, (info));
+}
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+class GeneratorFromBitmap : public SkImageGenerator {
+public:
+    GeneratorFromBitmap(const SkBitmap& bm) : SkImageGenerator(bm.info()), fBM(bm) {
+        if (!bm.isImmutable()) {
+            bm.copyTo(&fBM);
+        }
+    }
+
+protected:
+    bool onGetPixels(const SkImageInfo& info, void* pixels, size_t rowBytes,
+                     SkPMColor*, int*) override {
+        return fBM.readPixels(info, pixels, rowBytes, 0, 0);
+    }
+
+private:
+    SkBitmap fBM;
+};
+
+SkImageGenerator* SkImageGeneratorUtils::NewFromBitmap(const SkBitmap& bm) {
+    return SkNEW_ARGS(GeneratorFromBitmap, (bm));
+}
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+#if SK_SUPPORT_GPU
+
+#include "GrContext.h"
+#include "GrTexture.h"
+#include "SkGr.h"
+
+class GeneratorFromTexture : public SkImageGenerator {
+public:
+    GeneratorFromTexture(GrContext* ctx, GrTexture* tex, const SkImageInfo& info)
+        : SkImageGenerator(info), fCtx(ctx), fTexture(tex)
+    {}
+
+protected:
+    GrTexture* onGenerateTexture(GrContext* ctx, SkImageUsageType, const SkIRect* subset) override {
+        if (ctx) {
+            SkASSERT(ctx == fCtx.get());
+        }
+
+        if (!subset) {
+            return SkRef(fTexture.get());
+        }
+        // need to copy the subset into a new texture
+        GrSurfaceDesc desc = fTexture->desc();
+        desc.fWidth = subset->width();
+        desc.fHeight = subset->height();
+
+        GrTexture* dst = fCtx->textureProvider()->createTexture(desc, false);
+        fCtx->copySurface(dst, fTexture, *subset, SkIPoint::Make(0, 0));
+        return dst;
+    }
+private:
+    SkAutoTUnref<GrContext> fCtx;
+    SkAutoTUnref<GrTexture> fTexture;
+};
+#endif
+
+SkImageGenerator* SkImageGeneratorUtils::NewFromTexture(GrContext* ctx, GrTexture* tex) {
+#if SK_SUPPORT_GPU
+    if (ctx && tex) {
+        const GrSurfaceDesc desc = tex->desc();
+
+        SkColorType ct;
+        SkColorProfileType cpt;
+        if (!GrPixelConfig2ColorAndProfileType(desc.fConfig, &ct, &cpt)) {
+            return nullptr;
+        }
+        const SkAlphaType at = kPremul_SkAlphaType; // take isOpaque from caller?
+        SkImageInfo info = SkImageInfo::Make(desc.fWidth, desc.fHeight, ct, at, cpt);
+        return SkNEW_ARGS(GeneratorFromTexture, (ctx, tex, info));
+    }
+#endif
+    return nullptr;
+}
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+#include "SkImage.h"
+
+class GeneratorFromImage : public SkImageGenerator {
+public:
+    GeneratorFromImage(const SkImage* image, const SkImageInfo& info)
+        : SkImageGenerator(info), fImage(image) {}
+
+protected:
+    bool onGetPixels(const SkImageInfo& info, void* pixels, size_t rowBytes,
+                     SkPMColor*, int*) override {
+        return fImage->readPixels(info, pixels, rowBytes, 0, 0);
+    }
+
+    GrTexture* onGenerateTexture(GrContext* ctx, SkImageUsageType, const SkIRect* subset) override {
+        // waiting on https://code.google.com/p/skia/issues/detail?id=4233
+        return nullptr;
+    }
+
+private:
+    SkAutoTUnref<const SkImage> fImage;
+};
+
+SkImageGenerator* SkImageGeneratorUtils::NewFromImage(const SkImage* image) {
+    if (image) {
+        const SkColorType ct = kN32_SkColorType;
+        const SkAlphaType at = image->isOpaque() ? kOpaque_SkAlphaType : kPremul_SkAlphaType;
+        const SkImageInfo info = SkImageInfo::Make(image->width(), image->height(), ct, at);
+        return SkNEW_ARGS(GeneratorFromImage, (image, info));
+    }
+    return nullptr;
+}
+
+