/*
* Copyright 2015 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkCodec.h"
#include "SkCodecPriv.h"
#include "SkMath.h"
#include "SkSampledCodec.h"
#include "SkSampler.h"
#include "SkTemplates.h"
SkSampledCodec::SkSampledCodec(SkCodec* codec)
: INHERITED(codec)
{}
SkISize SkSampledCodec::accountForNativeScaling(int* sampleSizePtr, int* nativeSampleSize) const {
SkISize preSampledSize = this->codec()->getInfo().dimensions();
int sampleSize = *sampleSizePtr;
SkASSERT(sampleSize > 1);
if (nativeSampleSize) {
*nativeSampleSize = 1;
}
// Only JPEG supports native downsampling.
if (this->codec()->getEncodedFormat() == kJPEG_SkEncodedFormat) {
// See if libjpeg supports this scale directly
switch (sampleSize) {
case 2:
case 4:
case 8:
// This class does not need to do any sampling.
*sampleSizePtr = 1;
return this->codec()->getScaledDimensions(get_scale_from_sample_size(sampleSize));
default:
break;
}
// Check if sampleSize is a multiple of something libjpeg can support.
int remainder;
const int sampleSizes[] = { 8, 4, 2 };
for (int supportedSampleSize : sampleSizes) {
int actualSampleSize;
SkTDivMod(sampleSize, supportedSampleSize, &actualSampleSize, &remainder);
if (0 == remainder) {
float scale = get_scale_from_sample_size(supportedSampleSize);
// this->codec() will scale to this size.
preSampledSize = this->codec()->getScaledDimensions(scale);
// And then this class will sample it.
*sampleSizePtr = actualSampleSize;
if (nativeSampleSize) {
*nativeSampleSize = supportedSampleSize;
}
break;
}
}
}
return preSampledSize;
}
SkISize SkSampledCodec::onGetSampledDimensions(int sampleSize) const {
const SkISize size = this->accountForNativeScaling(&sampleSize);
return SkISize::Make(get_scaled_dimension(size.width(), sampleSize),
get_scaled_dimension(size.height(), sampleSize));
}
SkCodec::Result SkSampledCodec::onGetAndroidPixels(const SkImageInfo& info, void* pixels,
size_t rowBytes, const AndroidOptions& options) {
// Create an Options struct for the codec.
SkCodec::Options codecOptions;
codecOptions.fZeroInitialized = options.fZeroInitialized;
SkIRect* subset = options.fSubset;
if (!subset || subset->size() == this->codec()->getInfo().dimensions()) {
if (this->codec()->dimensionsSupported(info.dimensions())) {
return this->codec()->getPixels(info, pixels, rowBytes, &codecOptions,
options.fColorPtr, options.fColorCount);
}
// If the native codec does not support the requested scale, scale by sampling.
return this->sampledDecode(info, pixels, rowBytes, options);
}
// We are performing a subset decode.
int sampleSize = options.fSampleSize;
SkISize scaledSize = this->getSampledDimensions(sampleSize);
if (!this->codec()->dimensionsSupported(scaledSize)) {
// If the native codec does not support the requested scale, scale by sampling.
return this->sampledDecode(info, pixels, rowBytes, options);
}
// Calculate the scaled subset bounds.
int scaledSubsetX = subset->x() / sampleSize;
int scaledSubsetY = subset->y() / sampleSize;
int scaledSubsetWidth = info.width();
int scaledSubsetHeight = info.height();
// Start the scanline decode.
SkIRect scanlineSubset = SkIRect::MakeXYWH(scaledSubsetX, 0, scaledSubsetWidth,
scaledSize.height());
codecOptions.fSubset = &scanlineSubset;
SkCodec::Result result = this->codec()->startScanlineDecode(info.makeWH(scaledSize.width(),
scaledSize.height()), &codecOptions, options.fColorPtr, options.fColorCount);
if (SkCodec::kSuccess != result) {
return result;
}
// At this point, we are only concerned with subsetting. Either no scale was
// requested, or the this->codec() is handling the scale.
switch (this->codec()->getScanlineOrder()) {
case SkCodec::kTopDown_SkScanlineOrder:
case SkCodec::kNone_SkScanlineOrder: {
if (!this->codec()->skipScanlines(scaledSubsetY)) {
this->codec()->fillIncompleteImage(info, pixels, rowBytes, options.fZeroInitialized,
scaledSubsetHeight, 0);
return SkCodec::kIncompleteInput;
}
int decodedLines = this->codec()->getScanlines(pixels, scaledSubsetHeight, rowBytes);
if (decodedLines != scaledSubsetHeight) {
return SkCodec::kIncompleteInput;
}
return SkCodec::kSuccess;
}
default:
SkASSERT(false);
return SkCodec::kUnimplemented;
}
}
SkCodec::Result SkSampledCodec::sampledDecode(const SkImageInfo& info, void* pixels,
size_t rowBytes, const AndroidOptions& options) {
// We should only call this function when sampling.
SkASSERT(options.fSampleSize > 1);
// Create options struct for the codec.
SkCodec::Options sampledOptions;
sampledOptions.fZeroInitialized = options.fZeroInitialized;
// FIXME: This was already called by onGetAndroidPixels. Can we reduce that?
int sampleSize = options.fSampleSize;
int nativeSampleSize;
SkISize nativeSize = this->accountForNativeScaling(&sampleSize, &nativeSampleSize);
// Check if there is a subset.
SkIRect subset;
int subsetY = 0;
int subsetWidth = nativeSize.width();
int subsetHeight = nativeSize.height();
if (options.fSubset) {
// We will need to know about subsetting in the y-dimension in order to use the
// scanline decoder.
// Update the subset to account for scaling done by this->codec().
SkIRect* subsetPtr = options.fSubset;
// Do the divide ourselves, instead of calling get_scaled_dimension. If
// X and Y are 0, they should remain 0, rather than being upgraded to 1
// due to being smaller than the sampleSize.
const int subsetX = subsetPtr->x() / nativeSampleSize;
subsetY = subsetPtr->y() / nativeSampleSize;
subsetWidth = get_scaled_dimension(subsetPtr->width(), nativeSampleSize);
subsetHeight = get_scaled_dimension(subsetPtr->height(), nativeSampleSize);
// The scanline decoder only needs to be aware of subsetting in the x-dimension.
subset.setXYWH(subsetX, 0, subsetWidth, nativeSize.height());
sampledOptions.fSubset = ⊂
}
// Start the scanline decode.
SkCodec::Result result = this->codec()->startScanlineDecode(
info.makeWH(nativeSize.width(), nativeSize.height()), &sampledOptions,
options.fColorPtr, options.fColorCount);
if (SkCodec::kSuccess != result) {
return result;
}
SkSampler* sampler = this->codec()->getSampler(true);
if (!sampler) {
return SkCodec::kUnimplemented;
}
// Since we guarantee that output dimensions are always at least one (even if the sampleSize
// is greater than a given dimension), the input sampleSize is not always the sampleSize that
// we use in practice.
const int sampleX = subsetWidth / info.width();
const int sampleY = subsetHeight / info.height();
if (sampler->setSampleX(sampleX) != info.width()) {
return SkCodec::kInvalidScale;
}
if (get_scaled_dimension(subsetHeight, sampleY) != info.height()) {
return SkCodec::kInvalidScale;
}
const int samplingOffsetY = get_start_coord(sampleY);
const int startY = samplingOffsetY + subsetY;
int dstHeight = info.height();
switch(this->codec()->getScanlineOrder()) {
case SkCodec::kTopDown_SkScanlineOrder: {
if (!this->codec()->skipScanlines(startY)) {
this->codec()->fillIncompleteImage(info, pixels, rowBytes, options.fZeroInitialized,
dstHeight, 0);
return SkCodec::kIncompleteInput;
}
void* pixelPtr = pixels;
for (int y = 0; y < dstHeight; y++) {
if (1 != this->codec()->getScanlines(pixelPtr, 1, rowBytes)) {
this->codec()->fillIncompleteImage(info, pixels, rowBytes,
options.fZeroInitialized, dstHeight, y + 1);
return SkCodec::kIncompleteInput;
}
if (y < dstHeight - 1) {
if (!this->codec()->skipScanlines(sampleY - 1)) {
this->codec()->fillIncompleteImage(info, pixels, rowBytes,
options.fZeroInitialized, dstHeight, y + 1);
return SkCodec::kIncompleteInput;
}
}
pixelPtr = SkTAddOffset<void>(pixelPtr, rowBytes);
}
return SkCodec::kSuccess;
}
case SkCodec::kOutOfOrder_SkScanlineOrder:
case SkCodec::kBottomUp_SkScanlineOrder: {
// Note that these modes do not support subsetting.
SkASSERT(0 == subsetY && nativeSize.height() == subsetHeight);
int y;
for (y = 0; y < nativeSize.height(); y++) {
int srcY = this->codec()->nextScanline();
if (is_coord_necessary(srcY, sampleY, dstHeight)) {
void* pixelPtr = SkTAddOffset<void>(pixels,
rowBytes * get_dst_coord(srcY, sampleY));
if (1 != this->codec()->getScanlines(pixelPtr, 1, rowBytes)) {
break;
}
} else {
if (!this->codec()->skipScanlines(1)) {
break;
}
}
}
if (nativeSize.height() == y) {
return SkCodec::kSuccess;
}
// We handle filling uninitialized memory here instead of using this->codec().
// this->codec() does not know that we are sampling.
const uint32_t fillValue = this->codec()->getFillValue(info.colorType());
const SkImageInfo fillInfo = info.makeWH(info.width(), 1);
for (; y < nativeSize.height(); y++) {
int srcY = this->codec()->outputScanline(y);
if (!is_coord_necessary(srcY, sampleY, dstHeight)) {
continue;
}
void* rowPtr = SkTAddOffset<void>(pixels, rowBytes * get_dst_coord(srcY, sampleY));
SkSampler::Fill(fillInfo, rowPtr, rowBytes, fillValue, options.fZeroInitialized);
}
return SkCodec::kIncompleteInput;
}
case SkCodec::kNone_SkScanlineOrder: {
const int linesNeeded = subsetHeight - samplingOffsetY;
SkAutoTMalloc<uint8_t> storage(linesNeeded * rowBytes);
uint8_t* storagePtr = storage.get();
if (!this->codec()->skipScanlines(startY)) {
this->codec()->fillIncompleteImage(info, pixels, rowBytes, options.fZeroInitialized,
dstHeight, 0);
return SkCodec::kIncompleteInput;
}
int scanlines = this->codec()->getScanlines(storagePtr, linesNeeded, rowBytes);
for (int y = 0; y < dstHeight; y++) {
memcpy(pixels, storagePtr, info.minRowBytes());
storagePtr += sampleY * rowBytes;
pixels = SkTAddOffset<void>(pixels, rowBytes);
}
if (scanlines < dstHeight) {
// this->codec() has already handled filling uninitialized memory.
return SkCodec::kIncompleteInput;
}
return SkCodec::kSuccess;
}
default:
SkASSERT(false);
return SkCodec::kUnimplemented;
}
}