1/*
2 * Copyright 2006 The Android Open Source Project
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#include "SkColor.h"
9#include "SkColorData.h"
10#include "SkFixed.h"
11
12SkPMColor SkPreMultiplyARGB(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
13    return SkPremultiplyARGBInline(a, r, g, b);
14}
15
16SkPMColor SkPreMultiplyColor(SkColor c) {
17    return SkPremultiplyARGBInline(SkColorGetA(c), SkColorGetR(c),
18                                   SkColorGetG(c), SkColorGetB(c));
19}
20
21///////////////////////////////////////////////////////////////////////////////
22
23static inline SkScalar ByteToScalar(U8CPU x) {
24    SkASSERT(x <= 255);
25    return SkIntToScalar(x) / 255;
26}
27
28static inline SkScalar ByteDivToScalar(int numer, U8CPU denom) {
29    // cast to keep the answer signed
30    return SkIntToScalar(numer) / (int)denom;
31}
32
33void SkRGBToHSV(U8CPU r, U8CPU g, U8CPU b, SkScalar hsv[3]) {
34    SkASSERT(hsv);
35
36    unsigned min = SkMin32(r, SkMin32(g, b));
37    unsigned max = SkMax32(r, SkMax32(g, b));
38    unsigned delta = max - min;
39
40    SkScalar v = ByteToScalar(max);
41    SkASSERT(v >= 0 && v <= SK_Scalar1);
42
43    if (0 == delta) { // we're a shade of gray
44        hsv[0] = 0;
45        hsv[1] = 0;
46        hsv[2] = v;
47        return;
48    }
49
50    SkScalar s = ByteDivToScalar(delta, max);
51    SkASSERT(s >= 0 && s <= SK_Scalar1);
52
53    SkScalar h;
54    if (r == max) {
55        h = ByteDivToScalar(g - b, delta);
56    } else if (g == max) {
57        h = SkIntToScalar(2) + ByteDivToScalar(b - r, delta);
58    } else { // b == max
59        h = SkIntToScalar(4) + ByteDivToScalar(r - g, delta);
60    }
61
62    h *= 60;
63    if (h < 0) {
64        h += SkIntToScalar(360);
65    }
66    SkASSERT(h >= 0 && h < SkIntToScalar(360));
67
68    hsv[0] = h;
69    hsv[1] = s;
70    hsv[2] = v;
71}
72
73SkColor SkHSVToColor(U8CPU a, const SkScalar hsv[3]) {
74    SkASSERT(hsv);
75
76    SkScalar s = SkScalarPin(hsv[1], 0, 1);
77    SkScalar v = SkScalarPin(hsv[2], 0, 1);
78
79    U8CPU v_byte = SkScalarRoundToInt(v * 255);
80
81    if (SkScalarNearlyZero(s)) { // shade of gray
82        return SkColorSetARGB(a, v_byte, v_byte, v_byte);
83    }
84    SkScalar hx = (hsv[0] < 0 || hsv[0] >= SkIntToScalar(360)) ? 0 : hsv[0]/60;
85    SkScalar w = SkScalarFloorToScalar(hx);
86    SkScalar f = hx - w;
87
88    unsigned p = SkScalarRoundToInt((SK_Scalar1 - s) * v * 255);
89    unsigned q = SkScalarRoundToInt((SK_Scalar1 - (s * f)) * v * 255);
90    unsigned t = SkScalarRoundToInt((SK_Scalar1 - (s * (SK_Scalar1 - f))) * v * 255);
91
92    unsigned r, g, b;
93
94    SkASSERT((unsigned)(w) < 6);
95    switch ((unsigned)(w)) {
96        case 0: r = v_byte;  g = t;      b = p; break;
97        case 1: r = q;       g = v_byte; b = p; break;
98        case 2: r = p;       g = v_byte; b = t; break;
99        case 3: r = p;       g = q;      b = v_byte; break;
100        case 4: r = t;       g = p;      b = v_byte; break;
101        default: r = v_byte; g = p;      b = q; break;
102    }
103    return SkColorSetARGB(a, r, g, b);
104}
105
106///////////////////////////////////////////////////////////////////////////////////////////////////
107#include "SkPM4fPriv.h"
108#include "SkHalf.h"
109
110SkPM4f SkPM4f::FromPMColor(SkPMColor c) {
111    return From4f(swizzle_rb_if_bgra(Sk4f_fromL32(c)));
112}
113
114SkColor4f SkPM4f::unpremul() const {
115    float alpha = fVec[A];
116    if (0 == alpha) {
117        return { 0, 0, 0, 0 };
118    } else {
119        float invAlpha = 1 / alpha;
120        return { fVec[R] * invAlpha, fVec[G] * invAlpha, fVec[B] * invAlpha, alpha };
121    }
122}
123
124void SkPM4f::toF16(uint16_t half[4]) const {
125    for (int i = 0; i < 4; ++i) {
126        half[i] = SkFloatToHalf(fVec[i]);
127    }
128}
129
130uint64_t SkPM4f::toF16() const {
131    uint64_t value;
132    this->toF16(reinterpret_cast<uint16_t*>(&value));
133    return value;
134}
135
136SkPM4f SkPM4f::FromF16(const uint16_t half[4]) {
137    return {{
138        SkHalfToFloat(half[0]),
139        SkHalfToFloat(half[1]),
140        SkHalfToFloat(half[2]),
141        SkHalfToFloat(half[3])
142    }};
143}
144
145#ifdef SK_DEBUG
146void SkPM4f::assertIsUnit() const {
147    auto c4 = Sk4f::Load(fVec);
148    SkASSERT((c4 >= Sk4f(0)).allTrue() && (c4 <= Sk4f(1)).allTrue());
149}
150#endif
151
152///////////////////////////////////////////////////////////////////////////////////////////////////
153
154SkColor4f SkColor4f::FromColor(SkColor bgra) {
155    SkColor4f rgba;
156    swizzle_rb(Sk4f_fromS32(bgra)).store(rgba.vec());
157    return rgba;
158}
159
160SkColor SkColor4f::toSkColor() const {
161    return Sk4f_toS32(swizzle_rb(Sk4f::Load(this->vec())));
162}
163
164SkColor4f SkColor4f::Pin(float r, float g, float b, float a) {
165    SkColor4f c4;
166    Sk4f::Min(Sk4f::Max(Sk4f(r, g, b, a), Sk4f(0)), Sk4f(1)).store(c4.vec());
167    return c4;
168}
169
170SkPM4f SkColor4f::premul() const {
171    auto src = Sk4f::Load(this->pin().vec());
172    float srcAlpha = src[3];  // need the pinned version of our alpha
173    src = src * Sk4f(srcAlpha, srcAlpha, srcAlpha, 1);
174
175    return SkPM4f::From4f(src);
176}
177