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 #include "SkRect.h" 12 13 enum SubsetType { 14 kFullyInside_SubsetType, 15 kPartiallyInside_SubsetType, 16 kOutside_SubsetType, 17 }; 18 19 /* 20 * Corrects image subset offsets and dimensions in order to perform a valid decode. 21 * Also indicates if the image subset should be placed at an offset within the 22 * output bitmap. 23 * 24 * Values of output variables are undefined if the SubsetType is kInvalid. 25 * 26 * @param imageDims Original image dimensions. 27 * @param subset As input, the subset that the client requested. 28 * As output, the image subset that we will decode. 29 * @param outX The left offset of the image subset within the output bitmap. 30 * @param outY The top offset of the image subset within the output bitmap. 31 * 32 * @return An indication of how the subset is contained in the image. 33 * If the return value is kInvalid, values of output variables are undefined. 34 */ 35 inline SubsetType adjust_subset_rect(const SkISize& imageDims, SkIRect* subset, int* outX, 36 int* outY) { 37 // These must be at least zero, we can't start decoding the image at a negative coordinate. 38 int left = SkTMax(0, subset->fLeft); 39 int top = SkTMax(0, subset->fTop); 40 41 // If input offsets are less than zero, we decode to an offset location in the output bitmap. 42 *outX = left - subset->fLeft; 43 *outY = top - subset->fTop; 44 45 // Make sure we don't decode pixels past the edge of the image or past the edge of the subset. 46 int width = SkTMin(imageDims.width() - left, subset->width() - *outX); 47 int height = SkTMin(imageDims.height() - top, subset->height() - *outY); 48 if (width <= 0 || height <= 0) { 49 return SubsetType::kOutside_SubsetType; 50 } 51 52 subset->setXYWH(left, top, width, height); 53 if ((*outX != 0) || (*outY != 0) || (width != subset->width()) || 54 (height != subset->height())) { 55 return SubsetType::kPartiallyInside_SubsetType; 56 } 57 58 return SubsetType::kFullyInside_SubsetType; 59 } 60 61 #endif // SkBitmapRegionDecoderPriv_DEFINED 62
