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Diffstat (limited to 'src/codec/SkScaledCodec.cpp')
-rw-r--r-- | src/codec/SkScaledCodec.cpp | 261 |
1 files changed, 0 insertions, 261 deletions
diff --git a/src/codec/SkScaledCodec.cpp b/src/codec/SkScaledCodec.cpp deleted file mode 100644 index e0158b6b4e..0000000000 --- a/src/codec/SkScaledCodec.cpp +++ /dev/null @@ -1,261 +0,0 @@ -/* - * 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 "SkCodecPriv.h" -#include "SkScaledCodec.h" -#include "SkStream.h" -#include "SkWebpCodec.h" - - -SkCodec* SkScaledCodec::NewFromStream(SkStream* stream) { - bool isWebp = SkWebpCodec::IsWebp(stream); - if (!stream->rewind()) { - return NULL; - } - if (isWebp) { - // Webp codec supports scaling and subsetting natively - return SkWebpCodec::NewFromStream(stream); - } - - SkAutoTDelete<SkScanlineDecoder> scanlineDecoder(SkScanlineDecoder::NewFromStream(stream)); - if (NULL == scanlineDecoder) { - return NULL; - } - - // wrap in new SkScaledCodec - return SkNEW_ARGS(SkScaledCodec, (scanlineDecoder.detach())); -} - -SkCodec* SkScaledCodec::NewFromData(SkData* data) { - if (!data) { - return NULL; - } - return NewFromStream(SkNEW_ARGS(SkMemoryStream, (data))); -} - -SkScaledCodec::SkScaledCodec(SkScanlineDecoder* scanlineDecoder) - : INHERITED(scanlineDecoder->getInfo(), NULL) - , fScanlineDecoder(scanlineDecoder) -{} - -SkScaledCodec::~SkScaledCodec() {} - -// returns a scaled dimension based on the original dimension and the sampleSize -// NOTE: we round down here for scaled dimension to match the behavior of SkImageDecoder -static int get_scaled_dimension(int srcDimension, int sampleSize) { - if (sampleSize > srcDimension) { - return 1; - } - return srcDimension / sampleSize; -} - -static SkISize best_scaled_dimensions(const SkISize& origDims, const SkISize& nativeDims, - const SkISize& scaledCodecDims, float desiredScale) { - if (nativeDims == scaledCodecDims) { - // does not matter which to return if equal. Return here to skip below calculations - return nativeDims; - } - float idealWidth = origDims.width() * desiredScale; - float idealHeight = origDims.height() * desiredScale; - - // calculate difference between native dimensions and ideal dimensions - float nativeWDiff = SkTAbs(idealWidth - nativeDims.width()); - float nativeHDiff = SkTAbs(idealHeight - nativeDims.height()); - float nativeDiff = (nativeWDiff + nativeHDiff) / 2; - - // calculate difference between scaledCodec dimensions and ideal dimensions - float scaledCodecWDiff = SkTAbs(idealWidth - scaledCodecDims.width()); - float scaledCodecHDiff = SkTAbs(idealHeight - scaledCodecDims.height()); - float scaledCodecDiff = (scaledCodecWDiff + scaledCodecHDiff) / 2; - - // return dimensions closest to ideal dimensions. - // If the differences are equal, return nativeDims, as native scaling is more efficient. - return nativeDiff > scaledCodecDiff ? scaledCodecDims : nativeDims; - -} -/* - * Return a valid set of output dimensions for this decoder, given an input scale - */ -SkISize SkScaledCodec::onGetScaledDimensions(float desiredScale) const { - SkISize nativeDimensions = fScanlineDecoder->getScaledDimensions(desiredScale); - // support scaling down by integer numbers. Ex: 1/2, 1/3, 1/4 ... - SkISize scaledCodecDimensions; - if (desiredScale > 0.5f) { - // sampleSize = 1 - scaledCodecDimensions = fScanlineDecoder->getInfo().dimensions(); - } - // sampleSize determines the step size between samples - // Ex: sampleSize = 2, sample every second pixel in x and y directions - int sampleSize = int(1 / desiredScale); - - int scaledWidth = get_scaled_dimension(this->getInfo().width(), sampleSize); - int scaledHeight = get_scaled_dimension(this->getInfo().height(), sampleSize); - - // Return the calculated output dimensions for the given scale - scaledCodecDimensions = SkISize::Make(scaledWidth, scaledHeight); - - return best_scaled_dimensions(this->getInfo().dimensions(), nativeDimensions, - scaledCodecDimensions, desiredScale); -} - -// check if scaling to dstInfo size from srcInfo size using sampleSize is possible -static bool scaling_supported(const SkImageInfo& dstInfo, const SkImageInfo& srcInfo, - int* sampleX, int* sampleY) { - SkScaledCodec::ComputeSampleSize(dstInfo, srcInfo, sampleX, sampleY); - const int dstWidth = dstInfo.width(); - const int dstHeight = dstInfo.height(); - const int srcWidth = srcInfo.width(); - const int srcHeight = srcInfo.height(); - // only support down sampling, not up sampling - if (dstWidth > srcWidth || dstHeight > srcHeight) { - return false; - } - // check that srcWidth is scaled down by an integer value - if (get_scaled_dimension(srcWidth, *sampleX) != dstWidth) { - return false; - } - // check that src height is scaled down by an integer value - if (get_scaled_dimension(srcHeight, *sampleY) != dstHeight) { - return false; - } - // sampleX and sampleY should be equal unless the original sampleSize requested was larger - // than srcWidth or srcHeight. If so, the result of this is dstWidth or dstHeight = 1. - // This functionality allows for tall thin images to still be scaled down by scaling factors. - if (*sampleX != *sampleY){ - if (1 != dstWidth && 1 != dstHeight) { - return false; - } - } - return true; -} - -// calculates sampleSize in x and y direction -void SkScaledCodec::ComputeSampleSize(const SkImageInfo& dstInfo, const SkImageInfo& srcInfo, - int* sampleXPtr, int* sampleYPtr) { - int srcWidth = srcInfo.width(); - int dstWidth = dstInfo.width(); - int srcHeight = srcInfo.height(); - int dstHeight = dstInfo.height(); - - int sampleX = srcWidth / dstWidth; - int sampleY = srcHeight / dstHeight; - - // only support down sampling, not up sampling - SkASSERT(dstWidth <= srcWidth); - SkASSERT(dstHeight <= srcHeight); - - // sampleX and sampleY should be equal unless the original sampleSize requested was - // larger than srcWidth or srcHeight. - // If so, the result of this is dstWidth or dstHeight = 1. This functionality - // allows for tall thin images to still be scaled down by scaling factors. - - if (sampleX != sampleY){ - if (1 != dstWidth && 1 != dstHeight) { - - // rounding during onGetScaledDimensions can cause different sampleSizes - // Ex: srcWidth = 79, srcHeight = 20, sampleSize = 10 - // dstWidth = 7, dstHeight = 2, sampleX = 79/7 = 11, sampleY = 20/2 = 10 - // correct for this rounding by comparing width to sampleY and height to sampleX - - if (get_scaled_dimension(srcWidth, sampleY) == dstWidth) { - sampleX = sampleY; - } else if (get_scaled_dimension(srcHeight, sampleX) == dstHeight) { - sampleY = sampleX; - } - } - } - - if (sampleXPtr) { - *sampleXPtr = sampleX; - } - if (sampleYPtr) { - *sampleYPtr = sampleY; - } -} - -// TODO: Implement subsetting in onGetPixels which works when and when not sampling - -SkCodec::Result SkScaledCodec::onGetPixels(const SkImageInfo& requestedInfo, void* dst, - size_t rowBytes, const Options& options, - SkPMColor ctable[], int* ctableCount) { - - if (options.fSubset) { - // Subsets are not supported. - return kUnimplemented; - } - - Result result = fScanlineDecoder->start(requestedInfo, &options, ctable, ctableCount); - if (kSuccess == result) { - // native decode supported - return fScanlineDecoder->getScanlines(dst, requestedInfo.height(), rowBytes); - - } - - if (kInvalidScale != result) { - // no scaling requested - return result; - } - - // scaling requested - int sampleX; - int sampleY; - if (!scaling_supported(requestedInfo, fScanlineDecoder->getInfo(), &sampleX, &sampleY)) { - return kInvalidScale; - } - // set first sample pixel in y direction - int Y0 = sampleY >> 1; - - int dstHeight = requestedInfo.height(); - int srcHeight = fScanlineDecoder->getInfo().height(); - - SkImageInfo info = requestedInfo; - // use original height as scanlineDecoder does not support y sampling natively - info = info.makeWH(requestedInfo.width(), srcHeight); - - // update scanlineDecoder with new info - result = fScanlineDecoder->start(info, &options, ctable, ctableCount); - if (kSuccess != result) { - return result; - } - - const bool requiresPostYSampling = fScanlineDecoder->requiresPostYSampling(); - - if (requiresPostYSampling) { - SkAutoMalloc storage(srcHeight * rowBytes); - uint8_t* storagePtr = static_cast<uint8_t*>(storage.get()); - result = fScanlineDecoder->getScanlines(storagePtr, srcHeight, rowBytes); - if (kSuccess != result) { - return result; - } - storagePtr += Y0 * rowBytes; - for (int y = 0; y < dstHeight; y++) { - memcpy(dst, storagePtr, rowBytes); - storagePtr += sampleY * rowBytes; - dst = SkTAddOffset<void>(dst, rowBytes); - } - } else { - // does not require post y sampling - result = fScanlineDecoder->skipScanlines(Y0); - if (kSuccess != result) { - return result; - } - for (int y = 0; y < dstHeight; y++) { - result = fScanlineDecoder->getScanlines(dst, 1, rowBytes); - if (kSuccess != result) { - return result; - } - if (y < dstHeight - 1) { - result = fScanlineDecoder->skipScanlines(sampleY - 1); - if (kSuccess != result) { - return result; - } - } - dst = SkTAddOffset<void>(dst, rowBytes); - } - } - return kSuccess; -} |