Add the method isOpaque() to SkImage

tests/ImageIsOpaqueTest.cpp

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkTypes.h"
+#if SK_SUPPORT_GPU
+#include "GrContextFactory.h"
+#endif
+#include "SkImage.h"
+#include "SkSurface.h"
+
+#include "Test.h"
+
+DEF_TEST(ImageIsOpaqueTest, reporter) {
+    SkImageInfo infoTransparent = SkImageInfo::MakeN32Premul(5, 5);
+    SkAutoTUnref<SkSurface> surfaceTransparent(SkSurface::NewRaster(infoTransparent));
+    REPORTER_ASSERT(reporter, !surfaceTransparent->newImageSnapshot()->isOpaque());
+
+    SkImageInfo infoOpaque = SkImageInfo::MakeN32(5, 5, kOpaque_SkAlphaType);
+    SkAutoTUnref<SkSurface> surfaceOpaque(SkSurface::NewRaster(infoOpaque));
+    REPORTER_ASSERT(reporter, surfaceOpaque->newImageSnapshot()->isOpaque());
+}
+
+#if SK_SUPPORT_GPU
+
+DEF_GPUTEST(ImageIsOpaqueTest_GPU, reporter, factory) {
+    for (int i = 0; i < GrContextFactory::kGLContextTypeCnt; ++i) {
+        GrContextFactory::GLContextType glCtxType = (GrContextFactory::GLContextType) i;
+
+        if (!GrContextFactory::IsRenderingGLContext(glCtxType)) {
+            continue;
+        }
+
+        GrContext* context = factory->get(glCtxType);
+
+        if (NULL == context) {
+            continue;
+        }
+
+        SkImageInfo infoTransparent = SkImageInfo::MakeN32Premul(5, 5);
+        SkAutoTUnref<SkSurface> surfaceTransparent(SkSurface::NewRenderTarget(context, infoTransparent));
+        REPORTER_ASSERT(reporter, !surfaceTransparent->newImageSnapshot()->isOpaque());
+
+        SkImageInfo infoOpaque = SkImageInfo::MakeN32(5, 5, kOpaque_SkAlphaType);
+        SkAutoTUnref<SkSurface> surfaceOpaque(SkSurface::NewRenderTarget(context, infoOpaque));
+        REPORTER_ASSERT(reporter, !surfaceOpaque->newImageSnapshot()->isOpaque());
+
+    }
+}
+
+#endif