gfx/skia/trunk/src/core/SkDither.cpp

Tue, 06 Jan 2015 21:39:09 +0100

author
Michael Schloh von Bennewitz <michael@schloh.com>
date
Tue, 06 Jan 2015 21:39:09 +0100
branch
TOR_BUG_9701
changeset 8
97036ab72558
permissions
-rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

michael@0 1
michael@0 2 /*
michael@0 3 * Copyright 2011 Google Inc.
michael@0 4 *
michael@0 5 * Use of this source code is governed by a BSD-style license that can be
michael@0 6 * found in the LICENSE file.
michael@0 7 */
michael@0 8 #include "SkDither.h"
michael@0 9
michael@0 10 /* The base dither matrix we use to derive optimized ones for 565 and 4444
michael@0 11
michael@0 12 { 0, 32, 8, 40, 2, 34, 10, 42 },
michael@0 13 { 48, 16, 56, 24, 50, 18, 58, 26 },
michael@0 14 { 12, 44, 4, 36, 14, 46, 6, 38 },
michael@0 15 { 60, 28, 52, 20, 62, 30, 54, 22 },
michael@0 16 { 3, 35, 11, 43, 1, 33, 9, 41 },
michael@0 17 { 51, 19, 59, 27, 49, 17, 57, 25 },
michael@0 18 { 15, 47, 7, 39, 13, 45, 5, 37 },
michael@0 19 { 63, 31, 55, 23, 61, 29, 53, 21 }
michael@0 20
michael@0 21 The 4444 version only needs 4 bits, and given that we can reduce its size
michael@0 22 since the other 4x4 sub pieces all look the same once we truncate the bits.
michael@0 23
michael@0 24 The 565 version only needs 3 bits for red/blue, and only 2 bits for green.
michael@0 25 For simplicity, we store 3 bits, and have the dither macros for green know
michael@0 26 this, and they shift the dither value down by 1 to make it 2 bits.
michael@0 27 */
michael@0 28
michael@0 29 #ifdef ENABLE_DITHER_MATRIX_4X4
michael@0 30
michael@0 31 const uint8_t gDitherMatrix_4Bit_4X4[4][4] = {
michael@0 32 { 0, 8, 2, 10 },
michael@0 33 { 12, 4, 14, 6 },
michael@0 34 { 3, 11, 1, 9 },
michael@0 35 { 15, 7, 13, 5 }
michael@0 36 };
michael@0 37
michael@0 38 const uint8_t gDitherMatrix_3Bit_4X4[4][4] = {
michael@0 39 { 0, 4, 1, 5 },
michael@0 40 { 6, 2, 7, 3 },
michael@0 41 { 1, 5, 0, 4 },
michael@0 42 { 7, 3, 6, 2 }
michael@0 43 };
michael@0 44
michael@0 45 #else // used packed shorts for a scanlines worth of dither values
michael@0 46
michael@0 47 const uint16_t gDitherMatrix_4Bit_16[4] = {
michael@0 48 0xA280, 0x6E4C, 0x91B3, 0x5D7F
michael@0 49 };
michael@0 50
michael@0 51 const uint16_t gDitherMatrix_3Bit_16[4] = {
michael@0 52 0x5140, 0x3726, 0x4051, 0x2637
michael@0 53 };
michael@0 54
michael@0 55 #endif

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