gfx/skia/trunk/src/core/SkDither.cpp@deefc01c0e14
gfx/skia/trunk/src/core/SkDither.cpp
Thu, 15 Jan 2015 21:03:48 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 15 Jan 2015 21:03:48 +0100
- branch
- TOR_BUG_9701
- changeset 11
- deefc01c0e14
- permissions
- -rw-r--r--
Integrate friendly tips from Tor colleagues to make (or not) 4.5 alpha 3;
This includes removal of overloaded (but unused) methods, and addition of
a overlooked call to DataStruct::SetData(nsISupports, uint32_t, bool.)
2 /*
3 * Copyright 2011 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8 #include "SkDither.h"
10 /* The base dither matrix we use to derive optimized ones for 565 and 4444
12 { 0, 32, 8, 40, 2, 34, 10, 42 },
13 { 48, 16, 56, 24, 50, 18, 58, 26 },
14 { 12, 44, 4, 36, 14, 46, 6, 38 },
15 { 60, 28, 52, 20, 62, 30, 54, 22 },
16 { 3, 35, 11, 43, 1, 33, 9, 41 },
17 { 51, 19, 59, 27, 49, 17, 57, 25 },
18 { 15, 47, 7, 39, 13, 45, 5, 37 },
19 { 63, 31, 55, 23, 61, 29, 53, 21 }
21 The 4444 version only needs 4 bits, and given that we can reduce its size
22 since the other 4x4 sub pieces all look the same once we truncate the bits.
24 The 565 version only needs 3 bits for red/blue, and only 2 bits for green.
25 For simplicity, we store 3 bits, and have the dither macros for green know
26 this, and they shift the dither value down by 1 to make it 2 bits.
27 */
29 #ifdef ENABLE_DITHER_MATRIX_4X4
31 const uint8_t gDitherMatrix_4Bit_4X4[4][4] = {
32 { 0, 8, 2, 10 },
33 { 12, 4, 14, 6 },
34 { 3, 11, 1, 9 },
35 { 15, 7, 13, 5 }
36 };
38 const uint8_t gDitherMatrix_3Bit_4X4[4][4] = {
39 { 0, 4, 1, 5 },
40 { 6, 2, 7, 3 },
41 { 1, 5, 0, 4 },
42 { 7, 3, 6, 2 }
43 };
45 #else // used packed shorts for a scanlines worth of dither values
47 const uint16_t gDitherMatrix_4Bit_16[4] = {
48 0xA280, 0x6E4C, 0x91B3, 0x5D7F
49 };
51 const uint16_t gDitherMatrix_3Bit_16[4] = {
52 0x5140, 0x3726, 0x4051, 0x2637
53 };
55 #endif
