expose CGImage -> SkBitmap

src/ports/SkImageDecoder_CG.cpp

 /*
  * Copyright 2008 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCGUtils.h"
 #include "SkColorPriv.h"
 #include "SkImageDecoder.h"
@@ skipping 50 matching lines @@
     SkAutoTCallVProc<const void, CFRelease> arsrc(imageSrc);
 
     CGImageRef image = CGImageSourceCreateImageAtIndex(imageSrc, 0, NULL);
     if (NULL == image) {
         return false;
     }
     SkAutoTCallVProc<CGImage, CGImageRelease> arimage(image);
 
     const int width = SkToInt(CGImageGetWidth(image));
     const int height = SkToInt(CGImageGetHeight(image));
-    bm->setConfig(SkBitmap::kARGB_8888_Config, width, height);
+    SkImageInfo skinfo = SkImageInfo::MakeN32Premul(width, height);
+
+    bm->setConfig(skinfo);
     if (SkImageDecoder::kDecodeBounds_Mode == mode) {
         return true;
     }
 
     if (!this->allocPixelRef(bm, NULL)) {
         return false;
     }
+    
+    SkAutoLockPixels alp(*bm);
 
-    bm->lockPixels();
-    bm->eraseColor(SK_ColorTRANSPARENT);
-
-    CGColorSpaceRef cs = CGColorSpaceCreateDeviceRGB();
-    CGContextRef cg = CGBitmapContextCreate(bm->getPixels(), width, height, 8, bm->rowBytes(), cs, BITMAP_INFO);
-    CFRelease(cs);
-
-    CGContextDrawImage(cg, CGRectMake(0, 0, width, height), image);
-    CGContextRelease(cg);
+    if (!SkCopyPixelsFromCGImage(bm->info(), bm->rowBytes(), bm->getPixels(), image)) {
+        return false;
+    }
 
     CGImageAlphaInfo info = CGImageGetAlphaInfo(image);
     switch (info) {
         case kCGImageAlphaNone:
         case kCGImageAlphaNoneSkipLast:
         case kCGImageAlphaNoneSkipFirst:
             SkASSERT(SkBitmap::ComputeIsOpaque(*bm));
             bm->setAlphaType(kOpaque_SkAlphaType);
             break;
         default:
             // we don't know if we're opaque or not, so compute it.
             if (SkBitmap::ComputeIsOpaque(*bm)) {
                 bm->setAlphaType(kOpaque_SkAlphaType);
             }
     }
     if (!bm->isOpaque() && this->getRequireUnpremultipliedColors()) {
         // CGBitmapContext does not support unpremultiplied, so the image has been premultiplied.
         // Convert to unpremultiplied.
         for (int i = 0; i < width; ++i) {
             for (int j = 0; j < height; ++j) {
                 uint32_t* addr = bm->getAddr32(i, j);
                 *addr = SkUnPreMultiply::UnPreMultiplyPreservingByteOrder(*addr);
             }
         }
         bm->setAlphaType(kUnpremul_SkAlphaType);
     }
-    bm->unlockPixels();
     return true;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 extern SkImageDecoder* image_decoder_from_stream(SkStreamRewindable*);
 
 SkImageDecoder* SkImageDecoder::Factory(SkStreamRewindable* stream) {
     SkImageDecoder* decoder = image_decoder_from_stream(stream);
     if (NULL == decoder) {
@@ skipping 160 matching lines @@
 
     SkAutoTCallVProc<const void, CFRelease> arsrc(imageSrc);
     const CFStringRef name = CGImageSourceGetType(imageSrc);
     if (NULL == name) {
         return SkImageDecoder::kUnknown_Format;
     }
     return UTType_to_Format(name);
 }
 
 static SkImageDecoder_FormatReg gFormatReg(get_format_cg);