Add option to SkDecodingImageGenerator to require unpremul.

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 "SkData.h"
 #include "SkDecodingImageGenerator.h"
 #include "SkImageDecoder.h"
@@ skipping 157 matching lines @@
         return false;
     }
 
     SkAssertResult(fStream->rewind());
     SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(fStream));
     if (NULL == decoder.get()) {
         return false;
     }
     decoder->setDitherImage(fDitherImage);
     decoder->setSampleSize(fSampleSize);
+    decoder->setRequireUnpremultipliedColors(
+            info.fAlphaType == kUnpremul_SkAlphaType);
 
     SkBitmap bitmap;
     TargetAllocator allocator(fInfo, pixels, rowBytes);
     decoder->setAllocator(&allocator);
     // TODO: need to be able to pass colortype directly to decoder
     SkBitmap::Config legacyConfig = SkColorTypeToBitmapConfig(info.colorType());
     bool success = decoder->decode(fStream, &bitmap, legacyConfig,
                                    SkImageDecoder::kDecodePixels_Mode);
     decoder->setAllocator(NULL);
     if (!success) {
@@ skipping 29 matching lines @@
         // We do not support indexed color with SkImageGenerators,
         return NULL;
     }
     SkAssertResult(autoStream->rewind());
     SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(autoStream));
     if (NULL == decoder.get()) {
         return NULL;
     }
     SkBitmap bitmap;
     decoder->setSampleSize(opts.fSampleSize);
+    decoder->setRequireUnpremultipliedColors(opts.fRequireUnpremul);
     if (!decoder->decode(stream, &bitmap,
                          SkImageDecoder::kDecodeBounds_Mode)) {
         return NULL;
     }
     if (bitmap.config() == SkBitmap::kNo_Config) {
         return NULL;
     }
 
     SkImageInfo info = bitmap.info();
 
     if (!opts.fUseRequestedColorType) {
         // Use default
         if (kIndex_8_SkColorType == bitmap.colorType()) {
             // We don't support kIndex8 because we don't support
             // colortables in this workflow.
             info.fColorType = kPMColor_SkColorType;
         }
     } else {
         if (!bitmap.canCopyTo(opts.fRequestedColorType)) {
             SkASSERT(bitmap.colorType() != opts.fRequestedColorType);
             return NULL;  // Can not translate to needed config.
         }
         info.fColorType = opts.fRequestedColorType;
     }
+
+    if (opts.fRequireUnpremul && info.fAlphaType != kOpaque_SkAlphaType) {
+        info.fAlphaType = kUnpremul_SkAlphaType;
+    }
     return SkNEW_ARGS(DecodingImageGenerator,
                       (data, autoStream.detach(), info,
                        opts.fSampleSize, opts.fDitherImage));
 }
 
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
 
 SkImageGenerator* SkDecodingImageGenerator::Create(
@@ skipping 13 matching lines @@
         SkStreamRewindable* stream,
         const SkDecodingImageGenerator::Options& opts) {
     SkASSERT(stream != NULL);
     SkASSERT(stream->unique());
     if ((stream == NULL) || !stream->unique()) {
         SkSafeUnref(stream);
         return NULL;
     }
     return CreateDecodingImageGenerator(NULL, stream, opts);
 }