1 /*
2  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #ifndef MODULES_DESKTOP_CAPTURE_DIFFER_BLOCK_H_
12 #define MODULES_DESKTOP_CAPTURE_DIFFER_BLOCK_H_
13 
14 #include <stdint.h>
15 
16 namespace webrtc {
17 
18 // Size (in pixels) of each square block used for diffing. This must be a
19 // multiple of sizeof(uint64)/8.
20 const int kBlockSize = 32;
21 
22 // Format: BGRA 32 bit.
23 const int kBytesPerPixel = 4;
24 
25 // Low level function to compare 2 vectors of pixels of size kBlockSize. Returns
26 // whether the blocks differ.
27 bool VectorDifference(const uint8_t* image1, const uint8_t* image2);
28 
29 // Low level function to compare 2 blocks of pixels of size
30 // (kBlockSize, |height|).  Returns whether the blocks differ.
31 bool BlockDifference(const uint8_t* image1,
32                      const uint8_t* image2,
33                      int height,
34                      int stride);
35 
36 // Low level function to compare 2 blocks of pixels of size
37 // (kBlockSize, kBlockSize).  Returns whether the blocks differ.
38 bool BlockDifference(const uint8_t* image1, const uint8_t* image2, int stride);
39 
40 }  // namespace webrtc
41 
42 #endif  // MODULES_DESKTOP_CAPTURE_DIFFER_BLOCK_H_
43