Add SkImageGenerator Interface

src/images/SkDecodingImageGenerator.cpp

+/*
+ * 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 "SkDecodingImageGenerator.h"
+
+#include "SkBitmapFactory.h"
+#include "SkData.h"
+#include "SkImageDecoder.h"
+
+SkDecodingImageGenerator::SkDecodingImageGenerator(SkData* data)
+    : fData(data) {
+    SkASSERT(fData != NULL);
+    fData->ref();
+}
+
+SkDecodingImageGenerator::~SkDecodingImageGenerator() {
+    fData->unref();
+}
+
+SkData* SkDecodingImageGenerator::refEncodedData() {
+    fData->ref();
+    return fData;
+}
+
+bool SkDecodingImageGenerator::getInfo(SkImageInfo* info) {
+    return SkImageDecoder::DecodeMemoryToTarget(fData->data(),
+                                                fData->size(),
+                                                info, NULL);
+}
+
+bool SkDecodingImageGenerator::getPixels(const SkImageInfo& info,
+                                         void* pixels,
+                                         size_t rowBytes) {
+    SkBitmapFactory::Target target = {pixels, rowBytes};
+    SkImageInfo tmpInfo = info;
+    return SkImageDecoder::DecodeMemoryToTarget(fData->data(),
+                                                fData->size(),
+                                                &tmpInfo, &target);
+}