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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* functions that manipulate colors */
#include "nsCSSColorUtils.h"
#include "nsDebug.h"
#include <math.h>
// Weird color computing code stolen from winfe which was stolen
// from the xfe which was written originally by Eric Bina. So there.
#define RED_LUMINOSITY 299
#define GREEN_LUMINOSITY 587
#define BLUE_LUMINOSITY 114
#define INTENSITY_FACTOR 25
#define LUMINOSITY_FACTOR 75
void NS_GetSpecial3DColors(nscolor aResult[2], nscolor aBorderColor) {
const float kDarkerScale = 2.0f / 3.0f;
uint8_t r = NS_GET_R(aBorderColor);
uint8_t g = NS_GET_G(aBorderColor);
uint8_t b = NS_GET_B(aBorderColor);
uint8_t a = NS_GET_A(aBorderColor);
if (r == 0 && g == 0 && b == 0) {
// 0.3 * black
aResult[0] = NS_RGBA(76, 76, 76, a);
// 0.7 * black
aResult[1] = NS_RGBA(178, 178, 178, a);
return;
}
aResult[0] = NS_RGBA(uint8_t(r * kDarkerScale), uint8_t(g * kDarkerScale),
uint8_t(b * kDarkerScale), a);
aResult[1] = aBorderColor;
}
int NS_GetBrightness(uint8_t aRed, uint8_t aGreen, uint8_t aBlue) {
uint8_t intensity = (aRed + aGreen + aBlue) / 3;
uint8_t luminosity = NS_GetLuminosity(NS_RGB(aRed, aGreen, aBlue)) / 1000;
return ((intensity * INTENSITY_FACTOR) + (luminosity * LUMINOSITY_FACTOR)) /
100;
}
int32_t NS_GetLuminosity(nscolor aColor) {
// When aColor is not opaque, the perceived luminosity will depend
// on what color(s) aColor is ultimately drawn on top of, which we
// do not know.
NS_ASSERTION(NS_GET_A(aColor) == 255,
"impossible to compute luminosity of a non-opaque color");
return (NS_GET_R(aColor) * RED_LUMINOSITY +
NS_GET_G(aColor) * GREEN_LUMINOSITY +
NS_GET_B(aColor) * BLUE_LUMINOSITY);
}
// Function to convert RGB color space into the HSV colorspace
// Hue is the primary color defined from 0 to 359 degrees
// Saturation is defined from 0 to 255. The higher the number.. the deeper
// the color Value is the brightness of the color. 0 is black, 255 is white.
void NS_RGB2HSV(nscolor aColor, uint16_t& aHue, uint16_t& aSat,
uint16_t& aValue, uint8_t& aAlpha) {
uint8_t r, g, b;
int16_t delta, min, max, r1, b1, g1;
float hue;
r = NS_GET_R(aColor);
g = NS_GET_G(aColor);
b = NS_GET_B(aColor);
if (r > g) {
max = r;
min = g;
} else {
max = g;
min = r;
}
if (b > max) {
max = b;
}
if (b < min) {
min = b;
}
// value or brightness will always be the max of all the colors(RGB)
aValue = max;
delta = max - min;
aSat = (max != 0) ? ((delta * 255) / max) : 0;
r1 = r;
b1 = b;
g1 = g;
if (aSat == 0) {
hue = 1000;
} else {
if (r == max) {
hue = (float)(g1 - b1) / (float)delta;
} else if (g1 == max) {
hue = 2.0f + (float)(b1 - r1) / (float)delta;
} else {
hue = 4.0f + (float)(r1 - g1) / (float)delta;
}
}
if (hue < 999) {
hue *= 60;
if (hue < 0) {
hue += 360;
}
} else {
hue = 0;
}
aHue = (uint16_t)hue;
aAlpha = NS_GET_A(aColor);
}
// Function to convert HSV color space into the RGB colorspace
// Hue is the primary color defined from 0 to 359 degrees
// Saturation is defined from 0 to 255. The higher the number.. the deeper
// the color Value is the brightness of the color. 0 is black, 255 is white.
void NS_HSV2RGB(nscolor& aColor, uint16_t aHue, uint16_t aSat, uint16_t aValue,
uint8_t aAlpha) {
uint16_t r = 0, g = 0, b = 0;
uint16_t i, p, q, t;
double h, f, percent;
if (aSat == 0) {
// achromatic color, no hue is defined
r = aValue;
g = aValue;
b = aValue;
} else {
// hue in in degrees around the color wheel defined from
// 0 to 360 degrees.
if (aHue >= 360) {
aHue = 0;
}
// we break the color wheel into 6 areas.. these
// areas define how the saturation and value define the color.
// reds behave differently than the blues
h = (double)aHue / 60.0;
i = (uint16_t)floor(h);
f = h - (double)i;
percent = ((double)aValue /
255.0); // this needs to be a value from 0 to 1, so a percentage
// can be calculated of the saturation.
p = (uint16_t)(percent * (255 - aSat));
q = (uint16_t)(percent * (255 - (aSat * f)));
t = (uint16_t)(percent * (255 - (aSat * (1.0 - f))));
// i is guaranteed to never be larger than 5.
switch (i) {
case 0:
r = aValue;
g = t;
b = p;
break;
case 1:
r = q;
g = aValue;
b = p;
break;
case 2:
r = p;
g = aValue;
b = t;
break;
case 3:
r = p;
g = q;
b = aValue;
break;
case 4:
r = t;
g = p;
b = aValue;
break;
case 5:
r = aValue;
g = p;
b = q;
break;
}
}
aColor = NS_RGBA(r, g, b, aAlpha);
}
#undef RED_LUMINOSITY
#undef GREEN_LUMINOSITY
#undef BLUE_LUMINOSITY
#undef INTENSITY_FACTOR
#undef LUMINOSITY_FACTOR