Implement Raster Backend on Android Viewer App

tools/viewer/sk_app/android/RasterWindowContext_android.cpp

Index: tools/viewer/sk_app/android/RasterWindowContext_android.cpp
diff --git a/tools/viewer/sk_app/android/RasterWindowContext_android.cpp b/tools/viewer/sk_app/android/RasterWindowContext_android.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..306f291de8f80fadc10c5c2822a7b92b2b3096fa
--- /dev/null
+++ b/tools/viewer/sk_app/android/RasterWindowContext_android.cpp
@@ -0,0 +1,69 @@
+
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "RasterWindowContext_android.h"
+
+#include "SkSurface.h"
+#include "SkTypes.h"
+
+#include "Window_android.h"
+
+namespace sk_app {
+
+RasterWindowContext* RasterWindowContext::Create(void* platformData, const DisplayParams& params) {
+    RasterWindowContext* ctx = new RasterWindowContext_android(platformData, params);
+    if (!ctx->isValid()) {
+        delete ctx;
+        ctx = nullptr;
+    }
+    return ctx;
+}
+
+RasterWindowContext_android::RasterWindowContext_android(
+        void* platformData, const DisplayParams& params) {
+    fDisplayParams = params;
+    ContextPlatformData_android* androidPlatformData =
+            reinterpret_cast<ContextPlatformData_android*>(platformData);
+    fNativeWindow = androidPlatformData->fNativeWindow;
+    fWidth = ANativeWindow_getWidth(fNativeWindow);
+    fHeight = ANativeWindow_getHeight(fNativeWindow);
+    int32_t format;
+    switch(params.fColorType) {
+        case kRGBA_8888_SkColorType:
+            format = WINDOW_FORMAT_RGBA_8888;
+            break;
+        case kRGB_565_SkColorType:
+            format = WINDOW_FORMAT_RGB_565;
+            break;
+        default:
+            SkDEBUGFAIL("Unsupported Android color type");
+    }
+    ANativeWindow_setBuffersGeometry(fNativeWindow, fWidth, fHeight, format);
+}
+
+sk_sp<SkSurface> RasterWindowContext_android::getBackbufferSurface() {
+    if (nullptr == fBackbufferSurface) {
+        ANativeWindow_lock(fNativeWindow, &fBuffer, &fBounds);
+        const int bytePerPixel = fBuffer.format == WINDOW_FORMAT_RGB_565 ? 2 : 4;
+        SkImageInfo info = SkImageInfo::Make(fWidth, fHeight,
+                                             fDisplayParams.fColorType,
+                                             kOpaque_SkAlphaType,
+                                             fDisplayParams.fProfileType);
+        fBackbufferSurface = SkSurface::MakeRasterDirect(
+                info, fBuffer.bits, fBuffer.stride * bytePerPixel, nullptr);
+    }
+    return fBackbufferSurface;
+}
+
+
+void RasterWindowContext_android::swapBuffers() {
+    ANativeWindow_unlockAndPost(fNativeWindow);
+    fBackbufferSurface.reset(nullptr);
+}
+
+}   // namespace sk_app