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/*
* Copyright 2006 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkColor.h"
#include "SkColorPriv.h"
SkPMColor SkPreMultiplyARGB(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
return SkPremultiplyARGBInline(a, r, g, b);
}
SkPMColor SkPreMultiplyColor(SkColor c) {
return SkPremultiplyARGBInline(SkColorGetA(c), SkColorGetR(c),
SkColorGetG(c), SkColorGetB(c));
}
///////////////////////////////////////////////////////////////////////////////
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);
}
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