1
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 "SkColorMatrix.h"
9
10#define kRScale     0
11#define kGScale     6
12#define kBScale     12
13#define kAScale     18
14
15void SkColorMatrix::setIdentity() {
16    memset(fMat, 0, sizeof(fMat));
17    fMat[kRScale] = fMat[kGScale] = fMat[kBScale] = fMat[kAScale] = SK_Scalar1;
18}
19
20void SkColorMatrix::setScale(SkScalar rScale, SkScalar gScale, SkScalar bScale,
21                             SkScalar aScale) {
22    memset(fMat, 0, sizeof(fMat));
23    fMat[kRScale] = rScale;
24    fMat[kGScale] = gScale;
25    fMat[kBScale] = bScale;
26    fMat[kAScale] = aScale;
27}
28
29///////////////////////////////////////////////////////////////////////////////
30
31void SkColorMatrix::setRotate(Axis axis, SkScalar degrees) {
32    SkScalar S, C;
33
34    S = SkScalarSinCos(SkDegreesToRadians(degrees), &C);
35
36    this->setSinCos(axis, S, C);
37}
38
39void SkColorMatrix::setSinCos(Axis axis, SkScalar sine, SkScalar cosine) {
40    SkASSERT((unsigned)axis < 3);
41
42    static const uint8_t gRotateIndex[] = {
43        6, 7, 11, 12,
44        0, 10, 2, 12,
45        0, 1,  5,  6,
46    };
47    const uint8_t* index = gRotateIndex + axis * 4;
48
49    this->setIdentity();
50    fMat[index[0]] = cosine;
51    fMat[index[1]] = sine;
52    fMat[index[2]] = -sine;
53    fMat[index[3]] = cosine;
54}
55
56void SkColorMatrix::preRotate(Axis axis, SkScalar degrees) {
57    SkColorMatrix tmp;
58    tmp.setRotate(axis, degrees);
59    this->preConcat(tmp);
60}
61
62void SkColorMatrix::postRotate(Axis axis, SkScalar degrees) {
63    SkColorMatrix tmp;
64    tmp.setRotate(axis, degrees);
65    this->postConcat(tmp);
66}
67
68///////////////////////////////////////////////////////////////////////////////
69
70void SkColorMatrix::setConcat(const SkColorMatrix& matA,
71                              const SkColorMatrix& matB) {
72    SkScalar    tmp[20];
73    SkScalar*   result = fMat;
74
75    if (&matA == this || &matB == this) {
76        result = tmp;
77    }
78
79    const SkScalar* a = matA.fMat;
80    const SkScalar* b = matB.fMat;
81
82    int index = 0;
83    for (int j = 0; j < 20; j += 5) {
84        for (int i = 0; i < 4; i++) {
85            result[index++] =   SkScalarMul(a[j + 0], b[i + 0]) +
86                                SkScalarMul(a[j + 1], b[i + 5]) +
87                                SkScalarMul(a[j + 2], b[i + 10]) +
88                                SkScalarMul(a[j + 3], b[i + 15]);
89        }
90        result[index++] =   SkScalarMul(a[j + 0], b[4]) +
91                            SkScalarMul(a[j + 1], b[9]) +
92                            SkScalarMul(a[j + 2], b[14]) +
93                            SkScalarMul(a[j + 3], b[19]) +
94                            a[j + 4];
95    }
96
97    if (fMat != result) {
98        memcpy(fMat, result, sizeof(fMat));
99    }
100}
101
102///////////////////////////////////////////////////////////////////////////////
103
104static void setrow(SkScalar row[], SkScalar r, SkScalar g, SkScalar b) {
105    row[0] = r;
106    row[1] = g;
107    row[2] = b;
108}
109
110static const SkScalar kHueR = SkFloatToScalar(0.213f);
111static const SkScalar kHueG = SkFloatToScalar(0.715f);
112static const SkScalar kHueB = SkFloatToScalar(0.072f);
113
114void SkColorMatrix::setSaturation(SkScalar sat) {
115    memset(fMat, 0, sizeof(fMat));
116
117    const SkScalar R = SkScalarMul(kHueR, SK_Scalar1 - sat);
118    const SkScalar G = SkScalarMul(kHueG, SK_Scalar1 - sat);
119    const SkScalar B = SkScalarMul(kHueB, SK_Scalar1 - sat);
120
121    setrow(fMat +  0, R + sat, G, B);
122    setrow(fMat +  5, R, G + sat, B);
123    setrow(fMat + 10, R, G, B + sat);
124    fMat[18] = SK_Scalar1;
125}
126
127static const SkScalar kR2Y = SkFloatToScalar(0.299f);
128static const SkScalar kG2Y = SkFloatToScalar(0.587f);
129static const SkScalar kB2Y = SkFloatToScalar(0.114f);
130
131static const SkScalar kR2U = SkFloatToScalar(-0.16874f);
132static const SkScalar kG2U = SkFloatToScalar(-0.33126f);
133static const SkScalar kB2U = SkFloatToScalar(0.5f);
134
135static const SkScalar kR2V = SkFloatToScalar(0.5f);
136static const SkScalar kG2V = SkFloatToScalar(-0.41869f);
137static const SkScalar kB2V = SkFloatToScalar(-0.08131f);
138
139void SkColorMatrix::setRGB2YUV() {
140    memset(fMat, 0, sizeof(fMat));
141
142    setrow(fMat +  0, kR2Y, kG2Y, kB2Y);
143    setrow(fMat +  5, kR2U, kG2U, kB2U);
144    setrow(fMat + 10, kR2V, kG2V, kB2V);
145    fMat[18] = SK_Scalar1;
146}
147
148static const SkScalar kV2R = SkFloatToScalar(1.402f);
149static const SkScalar kU2G = SkFloatToScalar(-0.34414f);
150static const SkScalar kV2G = SkFloatToScalar(-0.71414f);
151static const SkScalar kU2B = SkFloatToScalar(1.772f);
152
153void SkColorMatrix::setYUV2RGB() {
154    memset(fMat, 0, sizeof(fMat));
155
156    setrow(fMat +  0, SK_Scalar1, 0, kV2R);
157    setrow(fMat +  5, SK_Scalar1, kU2G, kV2G);
158    setrow(fMat + 10, SK_Scalar1, kU2B, 0);
159    fMat[18] = SK_Scalar1;
160}
161
162