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      1 /*
      2  * Copyright 2015 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #include "SkAndroidCodec.h"
      9 #include "SkBitmapRegionCodec.h"
     10 #include "SkBitmapRegionDecoderPriv.h"
     11 #include "SkCodecPriv.h"
     12 
     13 SkBitmapRegionCodec::SkBitmapRegionCodec(SkAndroidCodec* codec)
     14     : INHERITED(codec->getInfo().width(), codec->getInfo().height())
     15     , fCodec(codec)
     16 {}
     17 
     18 bool SkBitmapRegionCodec::decodeRegion(SkBitmap* bitmap, SkBRDAllocator* allocator,
     19         const SkIRect& desiredSubset, int sampleSize, SkColorType dstColorType,
     20         bool requireUnpremul, sk_sp<SkColorSpace> dstColorSpace) {
     21 
     22     // Fix the input sampleSize if necessary.
     23     if (sampleSize < 1) {
     24         sampleSize = 1;
     25     }
     26 
     27     // The size of the output bitmap is determined by the size of the
     28     // requested subset, not by the size of the intersection of the subset
     29     // and the image dimensions.
     30     // If inputX is negative, we will need to place decoded pixels into the
     31     // output bitmap starting at a left offset.  Call this outX.
     32     // If outX is non-zero, subsetX must be zero.
     33     // If inputY is negative, we will need to place decoded pixels into the
     34     // output bitmap starting at a top offset.  Call this outY.
     35     // If outY is non-zero, subsetY must be zero.
     36     int outX;
     37     int outY;
     38     SkIRect subset = desiredSubset;
     39     SubsetType type = adjust_subset_rect(fCodec->getInfo().dimensions(), &subset, &outX, &outY);
     40     if (SubsetType::kOutside_SubsetType == type) {
     41         return false;
     42     }
     43 
     44     // Ask the codec for a scaled subset
     45     if (!fCodec->getSupportedSubset(&subset)) {
     46         SkCodecPrintf("Error: Could not get subset.\n");
     47         return false;
     48     }
     49     SkISize scaledSize = fCodec->getSampledSubsetDimensions(sampleSize, subset);
     50 
     51     // Create the image info for the decode
     52     SkAlphaType dstAlphaType = fCodec->computeOutputAlphaType(requireUnpremul);
     53     SkImageInfo decodeInfo = SkImageInfo::Make(scaledSize.width(), scaledSize.height(),
     54                                                dstColorType, dstAlphaType, dstColorSpace);
     55 
     56     // Initialize the destination bitmap
     57     int scaledOutX = 0;
     58     int scaledOutY = 0;
     59     int scaledOutWidth = scaledSize.width();
     60     int scaledOutHeight = scaledSize.height();
     61     if (SubsetType::kPartiallyInside_SubsetType == type) {
     62         scaledOutX = outX / sampleSize;
     63         scaledOutY = outY / sampleSize;
     64         // We need to be safe here because getSupportedSubset() may have modified the subset.
     65         const int extraX = SkTMax(0, desiredSubset.width() - outX - subset.width());
     66         const int extraY = SkTMax(0, desiredSubset.height() - outY - subset.height());
     67         const int scaledExtraX = extraX / sampleSize;
     68         const int scaledExtraY = extraY / sampleSize;
     69         scaledOutWidth += scaledOutX + scaledExtraX;
     70         scaledOutHeight += scaledOutY + scaledExtraY;
     71     }
     72     SkImageInfo outInfo = decodeInfo.makeWH(scaledOutWidth, scaledOutHeight);
     73     if (kGray_8_SkColorType == dstColorType) {
     74         // The legacy implementations of BitmapFactory and BitmapRegionDecoder
     75         // used kAlpha8 for grayscale images (before kGray8 existed).  While
     76         // the codec recognizes kGray8, we need to decode into a kAlpha8
     77         // bitmap in order to avoid a behavior change.
     78         outInfo = outInfo.makeColorType(kAlpha_8_SkColorType).makeAlphaType(kPremul_SkAlphaType);
     79     }
     80     bitmap->setInfo(outInfo);
     81     if (!bitmap->tryAllocPixels(allocator)) {
     82         SkCodecPrintf("Error: Could not allocate pixels.\n");
     83         return false;
     84     }
     85 
     86     // Zero the bitmap if the region is not completely within the image.
     87     // TODO (msarett): Can we make this faster by implementing it to only
     88     //                 zero parts of the image that we won't overwrite with
     89     //                 pixels?
     90     SkCodec::ZeroInitialized zeroInit = allocator ? allocator->zeroInit() :
     91             SkCodec::kNo_ZeroInitialized;
     92     if (SubsetType::kPartiallyInside_SubsetType == type &&
     93             SkCodec::kNo_ZeroInitialized == zeroInit) {
     94         void* pixels = bitmap->getPixels();
     95         size_t bytes = outInfo.computeByteSize(bitmap->rowBytes());
     96         memset(pixels, 0, bytes);
     97     }
     98 
     99     // Decode into the destination bitmap
    100     SkAndroidCodec::AndroidOptions options;
    101     options.fSampleSize = sampleSize;
    102     options.fSubset = &subset;
    103     options.fZeroInitialized = zeroInit;
    104     void* dst = bitmap->getAddr(scaledOutX, scaledOutY);
    105 
    106     SkCodec::Result result = fCodec->getAndroidPixels(decodeInfo, dst, bitmap->rowBytes(),
    107             &options);
    108     switch (result) {
    109         case SkCodec::kSuccess:
    110         case SkCodec::kIncompleteInput:
    111         case SkCodec::kErrorInInput:
    112             return true;
    113         default:
    114             SkCodecPrintf("Error: Could not get pixels with message \"%s\".\n",
    115                           SkCodec::ResultToString(result));
    116             return false;
    117     }
    118 }
    119