2 * Copyright 2013 Google Inc.
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
9 #include "SkDecodingImageGenerator.h"
10 #include "SkImageDecoder.h"
11 #include "SkImageInfo.h"
12 #include "SkImageGenerator.h"
13 #include "SkImagePriv.h"
19 * Special allocator used by getPixels(). Uses preallocated memory
22 class TargetAllocator : public SkBitmap::Allocator {
24 TargetAllocator(void* target,
28 SkBitmap::Config config)
35 bool isReady() { return (fTarget != NULL); }
37 virtual bool allocPixelRef(SkBitmap* bm, SkColorTable* ct) {
39 || (fConfig != bm->config())
40 || (fWidth != bm->width())
41 || (fHeight != bm->height())
43 // Call default allocator.
44 return bm->allocPixels(NULL, ct);
46 // make sure fRowBytes is correct.
47 bm->setConfig(fConfig, fWidth, fHeight, fRowBytes, bm->alphaType());
48 // TODO(halcanary): verify that all callers of this function
49 // will respect new RowBytes. Will be moot once rowbytes belongs
51 bm->setPixels(fTarget, NULL);
52 fTarget = NULL; // never alloc same pixels twice!
57 void* fTarget; // Block of memory to be supplied as pixel memory
58 // in allocPixelRef. Must be large enough to hold
59 // a bitmap described by fWidth, fHeight, and
61 size_t fRowBytes; // rowbytes for the destination bitmap
62 int fWidth; // Along with fHeight and fConfig, the information
63 int fHeight; // about the bitmap whose pixels this allocator is
64 // expected to allocate. If they do not match the
65 // bitmap passed to allocPixelRef, it is assumed
66 // that the bitmap will be copied to a bitmap with
67 // the correct info using this allocator, so the
68 // default allocator will be used instead of
70 SkBitmap::Config fConfig;
71 typedef SkBitmap::Allocator INHERITED;
74 // TODO(halcanary): Give this macro a better name and move it into SkTypes.h
76 #define SkCheckResult(expr, value) SkASSERT((value) == (expr))
78 #define SkCheckResult(expr, value) (void)(expr)
82 inline bool check_alpha(SkAlphaType reported, SkAlphaType actual) {
83 return ((reported == actual)
84 || ((reported == kPremul_SkAlphaType)
85 && (actual == kOpaque_SkAlphaType)));
90 ////////////////////////////////////////////////////////////////////////////////
92 SkDecodingImageGenerator::SkDecodingImageGenerator(
94 SkStreamRewindable* stream,
95 const SkImageInfo& info,
98 SkBitmap::Config requestedConfig)
102 , fSampleSize(sampleSize)
103 , fDitherImage(ditherImage)
104 , fRequestedConfig(requestedConfig) {
105 SkASSERT(stream != NULL);
106 SkSafeRef(fData); // may be NULL.
109 SkDecodingImageGenerator::~SkDecodingImageGenerator() {
114 bool SkDecodingImageGenerator::getInfo(SkImageInfo* info) {
121 SkData* SkDecodingImageGenerator::refEncodedData() {
122 // This functionality is used in `gm --serialize`
123 // Does not encode options.
125 return SkSafeRef(fData);
127 // TODO(halcanary): SkStreamRewindable needs a refData() function
128 // which returns a cheap copy of the underlying data.
129 if (!fStream->rewind()) {
132 size_t length = fStream->getLength();
136 void* buffer = sk_malloc_flags(length, 0);
137 SkCheckResult(fStream->read(buffer, length), length);
138 fData = SkData::NewFromMalloc(buffer, length);
139 return SkSafeRef(fData);
142 bool SkDecodingImageGenerator::getPixels(const SkImageInfo& info,
145 if (NULL == pixels) {
149 // The caller has specified a different info. This is an
150 // error for this kind of SkImageGenerator. Use the Options
151 // to change the settings.
154 int bpp = SkBitmap::ComputeBytesPerPixel(fRequestedConfig);
155 if (static_cast<size_t>(bpp * info.fWidth) > rowBytes) {
156 // The caller has specified a bad rowBytes.
160 SkAssertResult(fStream->rewind());
161 SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(fStream));
162 if (NULL == decoder.get()) {
165 decoder->setDitherImage(fDitherImage);
166 decoder->setSampleSize(fSampleSize);
169 TargetAllocator allocator(pixels, rowBytes, info.fWidth,
170 info.fHeight, fRequestedConfig);
171 decoder->setAllocator(&allocator);
172 bool success = decoder->decode(fStream, &bitmap, fRequestedConfig,
173 SkImageDecoder::kDecodePixels_Mode);
174 decoder->setAllocator(NULL);
178 if (allocator.isReady()) { // Did not use pixels!
180 SkASSERT(bitmap.canCopyTo(fRequestedConfig));
181 if (!bitmap.copyTo(&bm, fRequestedConfig, &allocator)
182 || allocator.isReady()) {
183 SkDEBUGFAIL("bitmap.copyTo(requestedConfig) failed.");
184 // Earlier we checked canCopyto(); we expect consistency.
187 SkASSERT(check_alpha(fInfo.fAlphaType, bm.alphaType()));
189 SkASSERT(check_alpha(fInfo.fAlphaType, bitmap.alphaType()));
194 SkImageGenerator* SkDecodingImageGenerator::Create(
196 const SkDecodingImageGenerator::Options& opts) {
197 SkASSERT(data != NULL);
201 SkStreamRewindable* stream = SkNEW_ARGS(SkMemoryStream, (data));
202 SkASSERT(stream != NULL);
203 SkASSERT(stream->unique());
204 return SkDecodingImageGenerator::Create(data, stream, opts);
207 SkImageGenerator* SkDecodingImageGenerator::Create(
208 SkStreamRewindable* stream,
209 const SkDecodingImageGenerator::Options& opts) {
210 SkASSERT(stream != NULL);
211 SkASSERT(stream->unique());
212 if ((stream == NULL) || !stream->unique()) {
216 return SkDecodingImageGenerator::Create(NULL, stream, opts);
219 // A contructor-type function that returns NULL on failure. This
220 // prevents the returned SkImageGenerator from ever being in a bad
221 // state. Called by both Create() functions
222 SkImageGenerator* SkDecodingImageGenerator::Create(
224 SkStreamRewindable* stream,
225 const SkDecodingImageGenerator::Options& opts) {
227 SkAutoTUnref<SkStreamRewindable> autoStream(stream); // always unref this.
228 if (opts.fUseRequestedColorType &&
229 (kIndex_8_SkColorType == opts.fRequestedColorType)) {
230 // We do not support indexed color with SkImageGenerators,
233 SkAssertResult(autoStream->rewind());
234 SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(autoStream));
235 if (NULL == decoder.get()) {
239 decoder->setSampleSize(opts.fSampleSize);
240 if (!decoder->decode(stream, &bitmap,
241 SkImageDecoder::kDecodeBounds_Mode)) {
244 if (bitmap.config() == SkBitmap::kNo_Config) {
249 SkBitmap::Config config;
251 if (!opts.fUseRequestedColorType) {
252 // Use default config.
253 if (SkBitmap::kIndex8_Config == bitmap.config()) {
254 // We don't support kIndex8 because we don't support
255 // colortables in this workflow.
256 config = SkBitmap::kARGB_8888_Config;
257 info.fWidth = bitmap.width();
258 info.fHeight = bitmap.height();
259 info.fColorType = kPMColor_SkColorType;
260 info.fAlphaType = bitmap.alphaType();
262 config = bitmap.config(); // Save for later!
263 if (!bitmap.asImageInfo(&info)) {
264 SkDEBUGFAIL("Getting SkImageInfo from bitmap failed.");
269 config = SkColorTypeToBitmapConfig(opts.fRequestedColorType);
270 if (!bitmap.canCopyTo(config)) {
271 SkASSERT(bitmap.config() != config);
272 return NULL; // Can not translate to needed config.
274 info.fWidth = bitmap.width();
275 info.fHeight = bitmap.height();
276 info.fColorType = opts.fRequestedColorType;
277 info.fAlphaType = bitmap.alphaType();
279 return SkNEW_ARGS(SkDecodingImageGenerator,
280 (data, autoStream.detach(), info,
281 opts.fSampleSize, opts.fDitherImage, config));