180bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru 280bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru/* 380bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru * Copyright 2011 Google Inc. 480bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru * 580bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru * Use of this source code is governed by a BSD-style license that can be 680bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru * found in the LICENSE file. 780bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru */ 880bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru#include "SkDither.h" 980bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru 1080bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru/* The base dither matrix we use to derive optimized ones for 565 and 4444 1180bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru 1280bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru { 0, 32, 8, 40, 2, 34, 10, 42 }, 1380bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru { 48, 16, 56, 24, 50, 18, 58, 26 }, 1480bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru { 12, 44, 4, 36, 14, 46, 6, 38 }, 1580bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru { 60, 28, 52, 20, 62, 30, 54, 22 }, 1680bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru { 3, 35, 11, 43, 1, 33, 9, 41 }, 1780bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru { 51, 19, 59, 27, 49, 17, 57, 25 }, 1880bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru { 15, 47, 7, 39, 13, 45, 5, 37 }, 1980bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru { 63, 31, 55, 23, 61, 29, 53, 21 } 2080bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru 2180bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru The 4444 version only needs 4 bits, and given that we can reduce its size 2280bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru since the other 4x4 sub pieces all look the same once we truncate the bits. 2380bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru 2480bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru The 565 version only needs 3 bits for red/blue, and only 2 bits for green. 2580bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru For simplicity, we store 3 bits, and have the dither macros for green know 2680bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru this, and they shift the dither value down by 1 to make it 2 bits. 2780bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru */ 2880bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru 2980bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru#ifdef ENABLE_DITHER_MATRIX_4X4 3080bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru 3180bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queruconst uint8_t gDitherMatrix_4Bit_4X4[4][4] = { 3280bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru { 0, 8, 2, 10 }, 3380bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru { 12, 4, 14, 6 }, 3480bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru { 3, 11, 1, 9 }, 3580bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru { 15, 7, 13, 5 } 3680bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru}; 3780bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru 3880bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queruconst uint8_t gDitherMatrix_3Bit_4X4[4][4] = { 3980bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru { 0, 4, 1, 5 }, 4080bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru { 6, 2, 7, 3 }, 4180bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru { 1, 5, 0, 4 }, 4280bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru { 7, 3, 6, 2 } 4380bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru}; 4480bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru 4580bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru#else // used packed shorts for a scanlines worth of dither values 4680bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru 4780bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queruconst uint16_t gDitherMatrix_4Bit_16[4] = { 4880bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru 0xA280, 0x6E4C, 0x91B3, 0x5D7F 4980bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru}; 5080bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru 5180bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queruconst uint16_t gDitherMatrix_3Bit_16[4] = { 5280bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru 0x5140, 0x3726, 0x4051, 0x2637 5380bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru}; 5480bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru 5580bacfeb4bda06541e8695bd502229727bccfeaJean-Baptiste Queru#endif 56