26ad17b8f8
Includes testing in DM and nanobench BUG=skia: Review URL: https://codereview.chromium.org/1402863002
64 lines
2.2 KiB
C
64 lines
2.2 KiB
C
/*
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* Copyright 2015 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkCodecTools_DEFINED
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#define SkCodecTools_DEFINED
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inline float get_scale_from_sample_size(uint32_t sampleSize) {
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return 1.0f / (float) sampleSize;
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}
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enum SubsetType {
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kFullyInside_SubsetType,
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kPartiallyInside_SubsetType,
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kOutside_SubsetType,
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};
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/*
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* Corrects image subset offsets and dimensions in order to perform a valid decode.
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* Also indicates if the image subset should be placed at an offset within the
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* output bitmap.
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*
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* Values of output variables are undefined if the SubsetType is kInvalid.
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*
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* @param imageDims Original image dimensions.
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* @param subset As input, the subset that the client requested.
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* As output, the image subset that we will decode.
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* @param outX The left offset of the image subset within the output bitmap.
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* @param outY The top offset of the image subset within the output bitmap.
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*
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* @return An indication of how the subset is contained in the image.
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* If the return value is kInvalid, values of output variables are undefined.
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*/
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inline SubsetType adjust_subset_rect(const SkISize& imageDims, SkIRect* subset, int* outX,
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int* outY) {
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// These must be at least zero, we can't start decoding the image at a negative coordinate.
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int left = SkTMax(0, subset->fLeft);
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int top = SkTMax(0, subset->fTop);
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// If input offsets are less than zero, we decode to an offset location in the output bitmap.
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*outX = left - subset->fLeft;
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*outY = top - subset->fTop;
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// Make sure we don't decode pixels past the edge of the image or past the edge of the subset.
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int width = SkTMin(imageDims.width() - left, subset->width() - *outX);
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int height = SkTMin(imageDims.height() - top, subset->height() - *outY);
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if (width <= 0 || height <= 0) {
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return SubsetType::kOutside_SubsetType;
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}
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subset->setXYWH(left, top, width, height);
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if ((*outX != 0) || (*outY != 0) || (width != subset->width()) ||
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(height != subset->height())) {
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return SubsetType::kPartiallyInside_SubsetType;
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}
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return SubsetType::kFullyInside_SubsetType;
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}
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#endif // SkCodecTools_DEFINED
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