formalize generate->bitmap

src/core/SkImageGenerator.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 "SkImageGenerator.h"
 #include "SkNextID.h"
 
@@ skipping 107 matching lines @@
     return nullptr;
 }
 
 bool SkImageGenerator::onGetPixels(const SkImageInfo& info, void* dst, size_t rb,
                                    SkPMColor* colors, int* colorCount) {
     return false;
 }
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
+#include "SkBitmap.h"
+#include "SkColorTable.h"
+
+static void release_malloc_proc(void* pixels, void* ctx) {
+    sk_free(pixels);
+}
+
+bool SkImageGenerator::tryGenerateBitmap(SkBitmap* bitmap, const SkImageInfo* infoPtr) {
+    const SkImageInfo info = infoPtr ? *infoPtr : this->getInfo();
+    const size_t rowBytes = info.minRowBytes();
+    const size_t pixelSize = info.getSafeSize(rowBytes);
+    if (0 == pixelSize) {
+        return false;
+    }
+
+    SkAutoFree pixelStorage(sk_malloc_flags(pixelSize, 0));
+    void* pixels = pixelStorage.get();
+    if (!pixels) {
+        return false;
+    }
+    
+    SkPMColor ctStorage[256];
+    int ctCount = 0;
+    
+    if (!this->getPixels(info, pixels, rowBytes, ctStorage, &ctCount)) {
+        return false;
+    }
+    
+    SkAutoTUnref<SkColorTable> ctable;
+    if (ctCount > 0) {
+        SkASSERT(kIndex_8_SkColorType == info.colorType());
+        ctable.reset(new SkColorTable(ctStorage, ctCount));
+    } else {
+        SkASSERT(kIndex_8_SkColorType != info.colorType());
+    }
+    
+    return bitmap->installPixels(info, pixelStorage.detach(), rowBytes, ctable,
+                                 release_malloc_proc, nullptr);
+}
+
 #include "SkGraphics.h"
 
 static SkGraphics::ImageGeneratorFromEncodedFactory gFactory;
 
 SkGraphics::ImageGeneratorFromEncodedFactory
 SkGraphics::SetImageGeneratorFromEncodedFactory(ImageGeneratorFromEncodedFactory factory)
 {
     ImageGeneratorFromEncodedFactory prev = gFactory;
     gFactory = factory;
     return prev;
 }
 
 SkImageGenerator* SkImageGenerator::NewFromEncoded(SkData* data) {
     if (nullptr == data) {
         return nullptr;
     }
     if (gFactory) {
         if (SkImageGenerator* generator = gFactory(data)) {
             return generator;
         }
     }
     return SkImageGenerator::NewFromEncodedImpl(data);
 }