1 /* 2 * Copyright 2015 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef SkBitmapRegionDecoderPriv_DEFINED 9 #define SkBitmapRegionDecoderPriv_DEFINED 10 11 enum SubsetType { 12 kFullyInside_SubsetType, 13 kPartiallyInside_SubsetType, 14 kOutside_SubsetType, 15 }; 16 17 /* 18 * Corrects image subset offsets and dimensions in order to perform a valid decode. 19 * Also indicates if the image subset should be placed at an offset within the 20 * output bitmap. 21 * 22 * Values of output variables are undefined if the SubsetType is kInvalid. 23 * 24 * @param imageDims Original image dimensions. 25 * @param subset As input, the subset that the client requested. 26 * As output, the image subset that we will decode. 27 * @param outX The left offset of the image subset within the output bitmap. 28 * @param outY The top offset of the image subset within the output bitmap. 29 * 30 * @return An indication of how the subset is contained in the image. 31 * If the return value is kInvalid, values of output variables are undefined. 32 */ 33 inline SubsetType adjust_subset_rect(const SkISize& imageDims, SkIRect* subset, int* outX, 34 int* outY) { 35 // These must be at least zero, we can't start decoding the image at a negative coordinate. 36 int left = SkTMax(0, subset->fLeft); 37 int top = SkTMax(0, subset->fTop); 38 39 // If input offsets are less than zero, we decode to an offset location in the output bitmap. 40 *outX = left - subset->fLeft; 41 *outY = top - subset->fTop; 42 43 // Make sure we don't decode pixels past the edge of the image or past the edge of the subset. 44 int width = SkTMin(imageDims.width() - left, subset->width() - *outX); 45 int height = SkTMin(imageDims.height() - top, subset->height() - *outY); 46 if (width <= 0 || height <= 0) { 47 return SubsetType::kOutside_SubsetType; 48 } 49 50 subset->setXYWH(left, top, width, height); 51 if ((*outX != 0) || (*outY != 0) || (width != subset->width()) || 52 (height != subset->height())) { 53 return SubsetType::kPartiallyInside_SubsetType; 54 } 55 56 return SubsetType::kFullyInside_SubsetType; 57 } 58 59 #endif // SkBitmapRegionDecoderPriv_DEFINED 60
