| /* libs/graphics/sgl/SkColor.cpp |
| ** |
| ** Copyright 2006, The Android Open Source Project |
| ** |
| ** Licensed under the Apache License, Version 2.0 (the "License"); |
| ** you may not use this file except in compliance with the License. |
| ** You may obtain a copy of the License at |
| ** |
| ** http://www.apache.org/licenses/LICENSE-2.0 |
| ** |
| ** Unless required by applicable law or agreed to in writing, software |
| ** distributed under the License is distributed on an "AS IS" BASIS, |
| ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| ** See the License for the specific language governing permissions and |
| ** limitations under the License. |
| */ |
| |
| #include "SkColor.h" |
| #include "SkColorPriv.h" |
| |
| SkPMColor SkPreMultiplyARGB(U8CPU a, U8CPU r, U8CPU g, U8CPU b) { |
| if (a != 255) { |
| #if 0 |
| unsigned scale = SkAlpha255To256(a); |
| r = SkAlphaMul(r, scale); |
| g = SkAlphaMul(g, scale); |
| b = SkAlphaMul(b, scale); |
| #else |
| r = SkMulDiv255Round(r, a); |
| g = SkMulDiv255Round(g, a); |
| b = SkMulDiv255Round(b, a); |
| #endif |
| } |
| return SkPackARGB32(a, r, g, b); |
| } |
| |
| SkPMColor SkPreMultiplyColor(SkColor c) { |
| unsigned a = SkColorGetA(c); |
| unsigned r = SkColorGetR(c); |
| unsigned g = SkColorGetG(c); |
| unsigned b = SkColorGetB(c); |
| |
| return SkPreMultiplyARGB(a, r, g, b); |
| } |
| |
| ////////////////////////////////////////////////////////////////////////////////////////////// |
| |
| static inline SkScalar ByteToScalar(U8CPU x) { |
| SkASSERT(x <= 255); |
| return SkIntToScalar(x) / 255; |
| } |
| |
| static inline SkScalar ByteDivToScalar(int numer, U8CPU denom) { |
| // cast to keep the answer signed |
| return SkIntToScalar(numer) / (int)denom; |
| } |
| |
| void SkRGBToHSV(U8CPU r, U8CPU g, U8CPU b, SkScalar hsv[3]) { |
| SkASSERT(hsv); |
| |
| unsigned min = SkMin32(r, SkMin32(g, b)); |
| unsigned max = SkMax32(r, SkMax32(g, b)); |
| unsigned delta = max - min; |
| |
| SkScalar v = ByteToScalar(max); |
| SkASSERT(v >= 0 && v <= SK_Scalar1); |
| |
| if (0 == delta) { // we're a shade of gray |
| hsv[0] = 0; |
| hsv[1] = 0; |
| hsv[2] = v; |
| return; |
| } |
| |
| SkScalar s = ByteDivToScalar(delta, max); |
| SkASSERT(s >= 0 && s <= SK_Scalar1); |
| |
| SkScalar h; |
| if (r == max) { |
| h = ByteDivToScalar(g - b, delta); |
| } else if (g == max) { |
| h = SkIntToScalar(2) + ByteDivToScalar(b - r, delta); |
| } else { // b == max |
| h = SkIntToScalar(4) + ByteDivToScalar(r - g, delta); |
| } |
| |
| h *= 60; |
| if (h < 0) { |
| h += SkIntToScalar(360); |
| } |
| SkASSERT(h >= 0 && h < SkIntToScalar(360)); |
| |
| hsv[0] = h; |
| hsv[1] = s; |
| hsv[2] = v; |
| } |
| |
| static inline U8CPU UnitScalarToByte(SkScalar x) { |
| if (x < 0) { |
| return 0; |
| } |
| if (x >= SK_Scalar1) { |
| return 255; |
| } |
| return SkScalarToFixed(x) >> 8; |
| } |
| |
| SkColor SkHSVToColor(U8CPU a, const SkScalar hsv[3]) { |
| SkASSERT(hsv); |
| |
| U8CPU s = UnitScalarToByte(hsv[1]); |
| U8CPU v = UnitScalarToByte(hsv[2]); |
| |
| if (0 == s) { // shade of gray |
| return SkColorSetARGB(a, v, v, v); |
| } |
| SkFixed hx = (hsv[0] < 0 || hsv[0] >= SkIntToScalar(360)) ? 0 : SkScalarToFixed(hsv[0]/60); |
| SkFixed f = hx & 0xFFFF; |
| |
| unsigned v_scale = SkAlpha255To256(v); |
| unsigned p = SkAlphaMul(255 - s, v_scale); |
| unsigned q = SkAlphaMul(255 - (s * f >> 16), v_scale); |
| unsigned t = SkAlphaMul(255 - (s * (SK_Fixed1 - f) >> 16), v_scale); |
| |
| unsigned r, g, b; |
| |
| SkASSERT((unsigned)(hx >> 16) < 6); |
| switch (hx >> 16) { |
| case 0: r = v; g = t; b = p; break; |
| case 1: r = q; g = v; b = p; break; |
| case 2: r = p; g = v; b = t; break; |
| case 3: r = p; g = q; b = v; break; |
| case 4: r = t; g = p; b = v; break; |
| default: r = v; g = p; b = q; break; |
| } |
| return SkColorSetARGB(a, r, g, b); |
| } |
| |