new image from backend desc

tests/SurfaceTest.cpp

Index: tests/SurfaceTest.cpp
diff --git a/tests/SurfaceTest.cpp b/tests/SurfaceTest.cpp
index 23a7f94f246f10e9cec299ed78565b6996c56ae4..a3ac216786c262882f2d59be04f7a23385779f16 100644
--- a/tests/SurfaceTest.cpp
+++ b/tests/SurfaceTest.cpp
@@ -617,3 +617,69 @@ DEF_GPUTEST(Surface, reporter, factory) {
     }
 #endif
 }
+
+#if SK_SUPPORT_GPU
+static SkImage* make_desc_image(GrContext* ctx, int w, int h, GrBackendObject texID, bool doCopy) {
+    GrBackendTextureDesc desc;
+    desc.fConfig = kSkia8888_GrPixelConfig;
+    // need to be a rendertarget for now...
+    desc.fFlags = kRenderTarget_GrBackendTextureFlag;
+    desc.fWidth = w;
+    desc.fHeight = h;
+    desc.fSampleCnt = 0;
+    desc.fTextureHandle = texID;
+    return doCopy ? SkImage::NewFromTextureCopy(ctx, desc) : SkImage::NewFromTexture(ctx, desc);
+}
+
+static void test_image_color(skiatest::Reporter* reporter, SkImage* image, SkPMColor expected) {
+    const SkImageInfo info = SkImageInfo::MakeN32Premul(1, 1);
+    SkPMColor pixel;
+    REPORTER_ASSERT(reporter, image->readPixels(info, &pixel, sizeof(pixel), 0, 0));
+    REPORTER_ASSERT(reporter, pixel == expected);
+}
+
+DEF_GPUTEST(SkImage_NewFromTexture, reporter, factory) {
+    GrContext* ctx = factory->get(GrContextFactory::kNative_GLContextType);
+    if (!ctx) {
+        REPORTER_ASSERT(reporter, false);
+        return;
+    }
+    GrTextureProvider* provider = ctx->textureProvider();
+    
+    const int w = 10;
+    const int h = 10;
+    SkPMColor storage[w * h];
+    const SkPMColor expected0 = SkPreMultiplyColor(SK_ColorRED);
+    sk_memset32(storage, expected0, w * h);
+    
+    GrSurfaceDesc desc;
+    desc.fFlags = kRenderTarget_GrSurfaceFlag;  // needs to be a rendertarget for readpixels();
+    desc.fOrigin = kDefault_GrSurfaceOrigin;
+    desc.fWidth = w;
+    desc.fHeight = h;
+    desc.fConfig = kSkia8888_GrPixelConfig;
+    desc.fSampleCnt = 0;
+    
+    SkAutoTUnref<GrTexture> tex(provider->createTexture(desc, false, storage, w * 4));
+    if (!tex) {
+        REPORTER_ASSERT(reporter, false);
+        return;
+    }
+    
+    GrBackendObject srcTex = tex->getTextureHandle();
+    SkAutoTUnref<SkImage> refImg(make_desc_image(ctx, w, h, srcTex, false));
+    SkAutoTUnref<SkImage> cpyImg(make_desc_image(ctx, w, h, srcTex, true));
+
+    test_image_color(reporter, refImg, expected0);
+    test_image_color(reporter, cpyImg, expected0);
+
+    // Now lets jam new colors into our "external" texture, and see if the images notice
+    const SkPMColor expected1 = SkPreMultiplyColor(SK_ColorBLUE);
+    sk_memset32(storage, expected1, w * h);
+    tex->writePixels(0, 0, w, h, kSkia8888_GrPixelConfig, storage, GrContext::kFlushWrites_PixelOp);
+
+    // We expect the ref'd image to see the new color, but cpy'd one should still see the old color
+    test_image_color(reporter, refImg, expected1);
+    test_image_color(reporter, cpyImg, expected0);
+}
+#endif