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* Copyright 2015 Google Inc.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef BitmapRegionDecoderPriv_DEFINED
#define BitmapRegionDecoderPriv_DEFINED
#include "include/core/SkRect.h"
enum SubsetType {
* Corrects image subset offsets and dimensions in order to perform a valid decode.
* Also indicates if the image subset should be placed at an offset within the
* output bitmap.
* Values of output variables are undefined if the SubsetType is kInvalid.
* @param imageDims Original image dimensions.
* @param subset As input, the subset that the client requested.
* As output, the image subset that we will decode.
* @param outX The left offset of the image subset within the output bitmap.
* @param outY The top offset of the image subset within the output bitmap.
* @return An indication of how the subset is contained in the image.
* If the return value is kInvalid, values of output variables are undefined.
inline SubsetType adjust_subset_rect(const SkISize& imageDims, SkIRect* subset, int* outX,
int* outY) {
// These must be at least zero, we can't start decoding the image at a negative coordinate.
int left = std::max(0, subset->fLeft);
int top = std::max(0, subset->fTop);
// If input offsets are less than zero, we decode to an offset location in the output bitmap.
*outX = left - subset->fLeft;
*outY = top - subset->fTop;
// Make sure we don't decode pixels past the edge of the image or past the edge of the subset.
int width = std::min(imageDims.width() - left, subset->width() - *outX);
int height = std::min(imageDims.height() - top, subset->height() - *outY);
if (width <= 0 || height <= 0) {
return SubsetType::kOutside_SubsetType;
subset->setXYWH(left, top, width, height);
if ((*outX != 0) || (*outY != 0) || (width != subset->width()) ||
(height != subset->height())) {
return SubsetType::kPartiallyInside_SubsetType;
return SubsetType::kFullyInside_SubsetType;
#endif // BitmapRegionDecoderPriv_DEFINED