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 SkPMColor SkPreMultiplyARGB(U8CPU a, U8CPU r, U8CPU g, U8CPU b) { 14 return SkPremultiplyARGBInline(a, r, g, b); 15 } 16 17 SkPMColor SkPreMultiplyColor(SkColor c) { 18 return SkPremultiplyARGBInline(SkColorGetA(c), SkColorGetR(c), 19 SkColorGetG(c), SkColorGetB(c)); 20 } 21 22 /////////////////////////////////////////////////////////////////////////////// 23 24 static inline SkScalar ByteToScalar(U8CPU x) { 25 SkASSERT(x <= 255); 26 return SkIntToScalar(x) / 255; 27 } 28 29 static inline SkScalar ByteDivToScalar(int numer, U8CPU denom) { 30 // cast to keep the answer signed 31 return SkIntToScalar(numer) / (int)denom; 32 } 33 34 void SkRGBToHSV(U8CPU r, U8CPU g, U8CPU b, SkScalar hsv[3]) { 35 SkASSERT(hsv); 36 37 unsigned min = SkMin32(r, SkMin32(g, b)); 38 unsigned max = SkMax32(r, SkMax32(g, b)); 39 unsigned delta = max - min; 40 41 SkScalar v = ByteToScalar(max); 42 SkASSERT(v >= 0 && v <= SK_Scalar1); 43 44 if (0 == delta) { // we're a shade of gray 45 hsv[0] = 0; 46 hsv[1] = 0; 47 hsv[2] = v; 48 return; 49 } 50 51 SkScalar s = ByteDivToScalar(delta, max); 52 SkASSERT(s >= 0 && s <= SK_Scalar1); 53 54 SkScalar h; 55 if (r == max) { 56 h = ByteDivToScalar(g - b, delta); 57 } else if (g == max) { 58 h = SkIntToScalar(2) + ByteDivToScalar(b - r, delta); 59 } else { // b == max 60 h = SkIntToScalar(4) + ByteDivToScalar(r - g, delta); 61 } 62 63 h *= 60; 64 if (h < 0) { 65 h += SkIntToScalar(360); 66 } 67 SkASSERT(h >= 0 && h < SkIntToScalar(360)); 68 69 hsv[0] = h; 70 hsv[1] = s; 71 hsv[2] = v; 72 } 73 74 static inline U8CPU UnitScalarToByte(SkScalar x) { 75 if (x < 0) { 76 return 0; 77 } 78 if (x >= SK_Scalar1) { 79 return 255; 80 } 81 return SkScalarToFixed(x) >> 8; 82 } 83 84 SkColor SkHSVToColor(U8CPU a, const SkScalar hsv[3]) { 85 SkASSERT(hsv); 86 87 U8CPU s = UnitScalarToByte(hsv[1]); 88 U8CPU v = UnitScalarToByte(hsv[2]); 89 90 if (0 == s) { // shade of gray 91 return SkColorSetARGB(a, v, v, v); 92 } 93 SkFixed hx = (hsv[0] < 0 || hsv[0] >= SkIntToScalar(360)) ? 0 : SkScalarToFixed(hsv[0]/60); 94 SkFixed f = hx & 0xFFFF; 95 96 unsigned v_scale = SkAlpha255To256(v); 97 unsigned p = SkAlphaMul(255 - s, v_scale); 98 unsigned q = SkAlphaMul(255 - (s * f >> 16), v_scale); 99 unsigned t = SkAlphaMul(255 - (s * (SK_Fixed1 - f) >> 16), v_scale); 100 101 unsigned r, g, b; 102 103 SkASSERT((unsigned)(hx >> 16) < 6); 104 switch (hx >> 16) { 105 case 0: r = v; g = t; b = p; break; 106 case 1: r = q; g = v; b = p; break; 107 case 2: r = p; g = v; b = t; break; 108 case 3: r = p; g = q; b = v; break; 109 case 4: r = t; g = p; b = v; break; 110 default: r = v; g = p; b = q; break; 111 } 112 return SkColorSetARGB(a, r, g, b); 113 } 114 115
