1 // Copyright 2013 Google Inc. All Rights Reserved. 2 // 3 // Use of this source code is governed by a BSD-style license 4 // that can be found in the COPYING file in the root of the source 5 // tree. An additional intellectual property rights grant can be found 6 // in the file PATENTS. All contributing project authors may 7 // be found in the AUTHORS file in the root of the source tree. 8 // ----------------------------------------------------------------------------- 9 // 10 // Utilities for processing transparent channel. 11 // 12 // Author: Skal (pascal.massimino@gmail.com) 13 14 #ifndef WEBP_UTILS_ALPHA_PROCESSING_H_ 15 #define WEBP_UTILS_ALPHA_PROCESSING_H_ 16 17 #include "../webp/types.h" 18 19 #ifdef __cplusplus 20 extern "C" { 21 #endif 22 23 // Pre-Multiply operation transforms x into x * A / 255 (where x=Y,R,G or B). 24 // Un-Multiply operation transforms x into x * 255 / A. 25 26 // Pre-Multiply or Un-Multiply (if 'inverse' is true) argb values in a row. 27 void WebPMultARGBRow(uint32_t* const ptr, int width, int inverse); 28 29 // Same a WebPMultARGBRow(), but for several rows. 30 void WebPMultARGBRows(uint8_t* ptr, int stride, int width, int num_rows, 31 int inverse); 32 33 // Same for a row of single values, with side alpha values. 34 void WebPMultRow(uint8_t* const ptr, const uint8_t* const alpha, 35 int width, int inverse); 36 37 // Same a WebPMultRow(), but for several 'num_rows' rows. 38 void WebPMultRows(uint8_t* ptr, int stride, 39 const uint8_t* alpha, int alpha_stride, 40 int width, int num_rows, int inverse); 41 42 #ifdef __cplusplus 43 } // extern "C" 44 #endif 45 46 #endif // WEBP_UTILS_ALPHA_PROCESSING_H_ 47