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
SkBitmapRegionCodec(SkAndroidCodec * codec)13 SkBitmapRegionCodec::SkBitmapRegionCodec(SkAndroidCodec* codec)
14 : INHERITED(codec->getInfo().width(), codec->getInfo().height())
15 , fCodec(codec)
16 {}
17
decodeRegion(SkBitmap * bitmap,SkBRDAllocator * allocator,const SkIRect & desiredSubset,int sampleSize,SkColorType dstColorType,bool requireUnpremul,sk_sp<SkColorSpace> dstColorSpace)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 = ⊂
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