1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/images/SkDecodingImageGenerator.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,256 @@
1.4 +/*
1.5 + * Copyright 2013 Google Inc.
1.6 + *
1.7 + * Use of this source code is governed by a BSD-style license that can be
1.8 + * found in the LICENSE file.
1.9 + */
1.10 +
1.11 +#include "SkData.h"
1.12 +#include "SkDecodingImageGenerator.h"
1.13 +#include "SkImageDecoder.h"
1.14 +#include "SkImageInfo.h"
1.15 +#include "SkImageGenerator.h"
1.16 +#include "SkImagePriv.h"
1.17 +#include "SkStream.h"
1.18 +#include "SkUtils.h"
1.19 +
1.20 +static bool equal_modulo_alpha(const SkImageInfo& a, const SkImageInfo& b) {
1.21 + return a.width() == b.width() && a.height() == b.height() &&
1.22 + a.colorType() == b.colorType();
1.23 +}
1.24 +
1.25 +namespace {
1.26 +/**
1.27 + * Special allocator used by getPixels(). Uses preallocated memory
1.28 + * provided if possible, else fall-back on the default allocator
1.29 + */
1.30 +class TargetAllocator : public SkBitmap::Allocator {
1.31 +public:
1.32 + TargetAllocator(const SkImageInfo& info,
1.33 + void* target,
1.34 + size_t rowBytes)
1.35 + : fInfo(info)
1.36 + , fTarget(target)
1.37 + , fRowBytes(rowBytes)
1.38 + {}
1.39 +
1.40 + bool isReady() { return (fTarget != NULL); }
1.41 +
1.42 + virtual bool allocPixelRef(SkBitmap* bm, SkColorTable* ct) {
1.43 + if (NULL == fTarget || !equal_modulo_alpha(fInfo, bm->info())) {
1.44 + // Call default allocator.
1.45 + return bm->allocPixels(NULL, ct);
1.46 + }
1.47 +
1.48 + // TODO(halcanary): verify that all callers of this function
1.49 + // will respect new RowBytes. Will be moot once rowbytes belongs
1.50 + // to PixelRef.
1.51 + bm->installPixels(fInfo, fTarget, fRowBytes, NULL, NULL);
1.52 +
1.53 + fTarget = NULL; // never alloc same pixels twice!
1.54 + return true;
1.55 + }
1.56 +
1.57 +private:
1.58 + const SkImageInfo fInfo;
1.59 + void* fTarget; // Block of memory to be supplied as pixel memory
1.60 + // in allocPixelRef. Must be large enough to hold
1.61 + // a bitmap described by fInfo and fRowBytes
1.62 + const size_t fRowBytes; // rowbytes for the destination bitmap
1.63 +
1.64 + typedef SkBitmap::Allocator INHERITED;
1.65 +};
1.66 +
1.67 +// TODO(halcanary): Give this macro a better name and move it into SkTypes.h
1.68 +#ifdef SK_DEBUG
1.69 + #define SkCheckResult(expr, value) SkASSERT((value) == (expr))
1.70 +#else
1.71 + #define SkCheckResult(expr, value) (void)(expr)
1.72 +#endif
1.73 +
1.74 +#ifdef SK_DEBUG
1.75 +inline bool check_alpha(SkAlphaType reported, SkAlphaType actual) {
1.76 + return ((reported == actual)
1.77 + || ((reported == kPremul_SkAlphaType)
1.78 + && (actual == kOpaque_SkAlphaType)));
1.79 +}
1.80 +#endif // SK_DEBUG
1.81 +
1.82 +} // namespace
1.83 +////////////////////////////////////////////////////////////////////////////////
1.84 +
1.85 +SkDecodingImageGenerator::SkDecodingImageGenerator(
1.86 + SkData* data,
1.87 + SkStreamRewindable* stream,
1.88 + const SkImageInfo& info,
1.89 + int sampleSize,
1.90 + bool ditherImage)
1.91 + : fData(data)
1.92 + , fStream(stream)
1.93 + , fInfo(info)
1.94 + , fSampleSize(sampleSize)
1.95 + , fDitherImage(ditherImage)
1.96 +{
1.97 + SkASSERT(stream != NULL);
1.98 + SkSafeRef(fData); // may be NULL.
1.99 +}
1.100 +
1.101 +SkDecodingImageGenerator::~SkDecodingImageGenerator() {
1.102 + SkSafeUnref(fData);
1.103 + fStream->unref();
1.104 +}
1.105 +
1.106 +bool SkDecodingImageGenerator::getInfo(SkImageInfo* info) {
1.107 + if (info != NULL) {
1.108 + *info = fInfo;
1.109 + }
1.110 + return true;
1.111 +}
1.112 +
1.113 +SkData* SkDecodingImageGenerator::refEncodedData() {
1.114 + // This functionality is used in `gm --serialize`
1.115 + // Does not encode options.
1.116 + if (fData != NULL) {
1.117 + return SkSafeRef(fData);
1.118 + }
1.119 + // TODO(halcanary): SkStreamRewindable needs a refData() function
1.120 + // which returns a cheap copy of the underlying data.
1.121 + if (!fStream->rewind()) {
1.122 + return NULL;
1.123 + }
1.124 + size_t length = fStream->getLength();
1.125 + if (0 == length) {
1.126 + return NULL;
1.127 + }
1.128 + void* buffer = sk_malloc_flags(length, 0);
1.129 + SkCheckResult(fStream->read(buffer, length), length);
1.130 + fData = SkData::NewFromMalloc(buffer, length);
1.131 + return SkSafeRef(fData);
1.132 +}
1.133 +
1.134 +bool SkDecodingImageGenerator::getPixels(const SkImageInfo& info,
1.135 + void* pixels,
1.136 + size_t rowBytes) {
1.137 + if (NULL == pixels) {
1.138 + return false;
1.139 + }
1.140 + if (fInfo != info) {
1.141 + // The caller has specified a different info. This is an
1.142 + // error for this kind of SkImageGenerator. Use the Options
1.143 + // to change the settings.
1.144 + return false;
1.145 + }
1.146 + if (info.minRowBytes() > rowBytes) {
1.147 + // The caller has specified a bad rowBytes.
1.148 + return false;
1.149 + }
1.150 +
1.151 + SkAssertResult(fStream->rewind());
1.152 + SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(fStream));
1.153 + if (NULL == decoder.get()) {
1.154 + return false;
1.155 + }
1.156 + decoder->setDitherImage(fDitherImage);
1.157 + decoder->setSampleSize(fSampleSize);
1.158 +
1.159 + SkBitmap bitmap;
1.160 + TargetAllocator allocator(fInfo, pixels, rowBytes);
1.161 + decoder->setAllocator(&allocator);
1.162 + // TODO: need to be able to pass colortype directly to decoder
1.163 + SkBitmap::Config legacyConfig = SkColorTypeToBitmapConfig(info.colorType());
1.164 + bool success = decoder->decode(fStream, &bitmap, legacyConfig,
1.165 + SkImageDecoder::kDecodePixels_Mode);
1.166 + decoder->setAllocator(NULL);
1.167 + if (!success) {
1.168 + return false;
1.169 + }
1.170 + if (allocator.isReady()) { // Did not use pixels!
1.171 + SkBitmap bm;
1.172 + SkASSERT(bitmap.canCopyTo(info.colorType()));
1.173 + bool copySuccess = bitmap.copyTo(&bm, info.colorType(), &allocator);
1.174 + if (!copySuccess || allocator.isReady()) {
1.175 + SkDEBUGFAIL("bitmap.copyTo(requestedConfig) failed.");
1.176 + // Earlier we checked canCopyto(); we expect consistency.
1.177 + return false;
1.178 + }
1.179 + SkASSERT(check_alpha(info.alphaType(), bm.alphaType()));
1.180 + } else {
1.181 + SkASSERT(check_alpha(info.alphaType(), bitmap.alphaType()));
1.182 + }
1.183 + return true;
1.184 +}
1.185 +
1.186 +SkImageGenerator* SkDecodingImageGenerator::Create(
1.187 + SkData* data,
1.188 + const SkDecodingImageGenerator::Options& opts) {
1.189 + SkASSERT(data != NULL);
1.190 + if (NULL == data) {
1.191 + return NULL;
1.192 + }
1.193 + SkStreamRewindable* stream = SkNEW_ARGS(SkMemoryStream, (data));
1.194 + SkASSERT(stream != NULL);
1.195 + SkASSERT(stream->unique());
1.196 + return SkDecodingImageGenerator::Create(data, stream, opts);
1.197 +}
1.198 +
1.199 +SkImageGenerator* SkDecodingImageGenerator::Create(
1.200 + SkStreamRewindable* stream,
1.201 + const SkDecodingImageGenerator::Options& opts) {
1.202 + SkASSERT(stream != NULL);
1.203 + SkASSERT(stream->unique());
1.204 + if ((stream == NULL) || !stream->unique()) {
1.205 + SkSafeUnref(stream);
1.206 + return NULL;
1.207 + }
1.208 + return SkDecodingImageGenerator::Create(NULL, stream, opts);
1.209 +}
1.210 +
1.211 +// A contructor-type function that returns NULL on failure. This
1.212 +// prevents the returned SkImageGenerator from ever being in a bad
1.213 +// state. Called by both Create() functions
1.214 +SkImageGenerator* SkDecodingImageGenerator::Create(
1.215 + SkData* data,
1.216 + SkStreamRewindable* stream,
1.217 + const SkDecodingImageGenerator::Options& opts) {
1.218 + SkASSERT(stream);
1.219 + SkAutoTUnref<SkStreamRewindable> autoStream(stream); // always unref this.
1.220 + if (opts.fUseRequestedColorType &&
1.221 + (kIndex_8_SkColorType == opts.fRequestedColorType)) {
1.222 + // We do not support indexed color with SkImageGenerators,
1.223 + return NULL;
1.224 + }
1.225 + SkAssertResult(autoStream->rewind());
1.226 + SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(autoStream));
1.227 + if (NULL == decoder.get()) {
1.228 + return NULL;
1.229 + }
1.230 + SkBitmap bitmap;
1.231 + decoder->setSampleSize(opts.fSampleSize);
1.232 + if (!decoder->decode(stream, &bitmap,
1.233 + SkImageDecoder::kDecodeBounds_Mode)) {
1.234 + return NULL;
1.235 + }
1.236 + if (bitmap.config() == SkBitmap::kNo_Config) {
1.237 + return NULL;
1.238 + }
1.239 +
1.240 + SkImageInfo info = bitmap.info();
1.241 +
1.242 + if (!opts.fUseRequestedColorType) {
1.243 + // Use default
1.244 + if (kIndex_8_SkColorType == bitmap.colorType()) {
1.245 + // We don't support kIndex8 because we don't support
1.246 + // colortables in this workflow.
1.247 + info.fColorType = kPMColor_SkColorType;
1.248 + }
1.249 + } else {
1.250 + if (!bitmap.canCopyTo(opts.fRequestedColorType)) {
1.251 + SkASSERT(bitmap.colorType() != opts.fRequestedColorType);
1.252 + return NULL; // Can not translate to needed config.
1.253 + }
1.254 + info.fColorType = opts.fRequestedColorType;
1.255 + }
1.256 + return SkNEW_ARGS(SkDecodingImageGenerator,
1.257 + (data, autoStream.detach(), info,
1.258 + opts.fSampleSize, opts.fDitherImage));
1.259 +}
