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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 SkBitmapRegionDecoderPriv_DEFINED
- #define SkBitmapRegionDecoderPriv_DEFINED
- #include "include/core/SkRect.h"
- enum SubsetType {
- kFullyInside_SubsetType,
- kPartiallyInside_SubsetType,
- kOutside_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 = SkTMax(0, subset->fLeft);
- int top = SkTMax(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 = SkTMin(imageDims.width() - left, subset->width() - *outX);
- int height = SkTMin(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 // SkBitmapRegionDecoderPriv_DEFINED
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