1 :
2 : /*
3 : * Copyright 2006 The Android Open Source Project
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 :
9 :
10 : #include "SkColor.h"
11 : #include "SkColorPriv.h"
12 :
13 0 : SkPMColor SkPreMultiplyARGB(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
14 0 : return SkPremultiplyARGBInline(a, r, g, b);
15 : }
16 :
17 0 : SkPMColor SkPreMultiplyColor(SkColor c) {
18 : return SkPremultiplyARGBInline(SkColorGetA(c), SkColorGetR(c),
19 0 : SkColorGetG(c), SkColorGetB(c));
20 : }
21 :
22 : ///////////////////////////////////////////////////////////////////////////////
23 :
24 0 : static inline SkScalar ByteToScalar(U8CPU x) {
25 0 : SkASSERT(x <= 255);
26 0 : return SkIntToScalar(x) / 255;
27 : }
28 :
29 0 : static inline SkScalar ByteDivToScalar(int numer, U8CPU denom) {
30 : // cast to keep the answer signed
31 0 : return SkIntToScalar(numer) / (int)denom;
32 : }
33 :
34 0 : void SkRGBToHSV(U8CPU r, U8CPU g, U8CPU b, SkScalar hsv[3]) {
35 0 : SkASSERT(hsv);
36 :
37 0 : unsigned min = SkMin32(r, SkMin32(g, b));
38 0 : unsigned max = SkMax32(r, SkMax32(g, b));
39 0 : unsigned delta = max - min;
40 :
41 0 : SkScalar v = ByteToScalar(max);
42 0 : SkASSERT(v >= 0 && v <= SK_Scalar1);
43 :
44 0 : if (0 == delta) { // we're a shade of gray
45 0 : hsv[0] = 0;
46 0 : hsv[1] = 0;
47 0 : hsv[2] = v;
48 0 : return;
49 : }
50 :
51 0 : SkScalar s = ByteDivToScalar(delta, max);
52 0 : SkASSERT(s >= 0 && s <= SK_Scalar1);
53 :
54 : SkScalar h;
55 0 : if (r == max) {
56 0 : h = ByteDivToScalar(g - b, delta);
57 0 : } else if (g == max) {
58 0 : h = SkIntToScalar(2) + ByteDivToScalar(b - r, delta);
59 : } else { // b == max
60 0 : h = SkIntToScalar(4) + ByteDivToScalar(r - g, delta);
61 : }
62 :
63 0 : h *= 60;
64 0 : if (h < 0) {
65 0 : h += SkIntToScalar(360);
66 : }
67 0 : SkASSERT(h >= 0 && h < SkIntToScalar(360));
68 :
69 0 : hsv[0] = h;
70 0 : hsv[1] = s;
71 0 : hsv[2] = v;
72 : }
73 :
74 0 : static inline U8CPU UnitScalarToByte(SkScalar x) {
75 0 : if (x < 0) {
76 0 : return 0;
77 : }
78 0 : if (x >= SK_Scalar1) {
79 0 : return 255;
80 : }
81 0 : return SkScalarToFixed(x) >> 8;
82 : }
83 :
84 0 : SkColor SkHSVToColor(U8CPU a, const SkScalar hsv[3]) {
85 0 : SkASSERT(hsv);
86 :
87 0 : U8CPU s = UnitScalarToByte(hsv[1]);
88 0 : U8CPU v = UnitScalarToByte(hsv[2]);
89 :
90 0 : if (0 == s) { // shade of gray
91 0 : return SkColorSetARGB(a, v, v, v);
92 : }
93 0 : SkFixed hx = (hsv[0] < 0 || hsv[0] >= SkIntToScalar(360)) ? 0 : SkScalarToFixed(hsv[0]/60);
94 0 : SkFixed f = hx & 0xFFFF;
95 :
96 0 : unsigned v_scale = SkAlpha255To256(v);
97 0 : unsigned p = SkAlphaMul(255 - s, v_scale);
98 0 : unsigned q = SkAlphaMul(255 - (s * f >> 16), v_scale);
99 0 : unsigned t = SkAlphaMul(255 - (s * (SK_Fixed1 - f) >> 16), v_scale);
100 :
101 : unsigned r, g, b;
102 :
103 0 : SkASSERT((unsigned)(hx >> 16) < 6);
104 0 : switch (hx >> 16) {
105 0 : case 0: r = v; g = t; b = p; break;
106 0 : case 1: r = q; g = v; b = p; break;
107 0 : case 2: r = p; g = v; b = t; break;
108 0 : case 3: r = p; g = q; b = v; break;
109 0 : case 4: r = t; g = p; b = v; break;
110 0 : default: r = v; g = p; b = q; break;
111 : }
112 0 : return SkColorSetARGB(a, r, g, b);
113 : }
114 :
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