gecko-dev/layout/base/nsCSSColorUtils.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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* License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is
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* Portions created by the Initial Developer are Copyright (C) 1998
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#include "nsCSSColorUtils.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 30
#define GREEN_LUMINOSITY 59
#define BLUE_LUMINOSITY 11
#define INTENSITY_FACTOR 25
#define LIGHT_FACTOR 0
#define LUMINOSITY_FACTOR 75
#define MAX_COLOR 255
#define COLOR_DARK_THRESHOLD 51
#define COLOR_LIGHT_THRESHOLD 204
#define COLOR_LITE_BS_FACTOR 45
#define COLOR_LITE_TS_FACTOR 70
#define COLOR_DARK_BS_FACTOR 30
#define COLOR_DARK_TS_FACTOR 50
#define LIGHT_GRAY NS_RGB(192, 192, 192)
#define DARK_GRAY NS_RGB(96, 96, 96)
#define WHITE NS_RGB(255, 255, 255)
#define BLACK NS_RGB(0, 0, 0)
#define MAX_BRIGHTNESS 254
#define MAX_DARKNESS 0
void NS_Get3DColors(nscolor aResult[2], nscolor aBackgroundColor)
{
int rb = NS_GET_R(aBackgroundColor);
int gb = NS_GET_G(aBackgroundColor);
int bb = NS_GET_B(aBackgroundColor);
int brightness = NS_GetBrightness(rb,gb,bb);
int f0, f1;
if (brightness < COLOR_DARK_THRESHOLD) {
f0 = COLOR_DARK_BS_FACTOR;
f1 = COLOR_DARK_TS_FACTOR;
} else if (brightness > COLOR_LIGHT_THRESHOLD) {
f0 = COLOR_LITE_BS_FACTOR;
f1 = COLOR_LITE_TS_FACTOR;
} else {
f0 = COLOR_DARK_BS_FACTOR +
(brightness *
(COLOR_LITE_BS_FACTOR - COLOR_DARK_BS_FACTOR) / MAX_COLOR);
f1 = COLOR_DARK_TS_FACTOR +
(brightness *
(COLOR_LITE_TS_FACTOR - COLOR_DARK_TS_FACTOR) / MAX_COLOR);
}
int r = rb - (f0 * rb / 100);
int g = gb - (f0 * gb / 100);
int b = bb - (f0 * bb / 100);
aResult[0] = NS_RGB(r, g, b);
if ((r == rb) && (g == gb) && (b == bb)) {
aResult[0] = (aBackgroundColor == BLACK) ? DARK_GRAY : BLACK;
}
r = rb + (f1 * (MAX_COLOR - rb) / 100);
if (r > 255) r = 255;
g = gb + (f1 * (MAX_COLOR - gb) / 100);
if (g > 255) g = 255;
b = bb + (f1 * (MAX_COLOR - bb) / 100);
if (b > 255) b = 255;
aResult[1] = NS_RGB(r, g, b);
if ((r == rb) && (g == gb) && (b == bb)) {
aResult[1] = (aBackgroundColor == WHITE) ? LIGHT_GRAY : WHITE;
}
}
void NS_GetSpecial3DColors(nscolor aResult[2],
nscolor aBackgroundColor,
nscolor aBorderColor)
{
PRUint8 f0, f1;
PRUint8 r, g, b;
PRUint8 rb = NS_GET_R(aBorderColor);
PRUint8 gb = NS_GET_G(aBorderColor);
PRUint8 bb = NS_GET_B(aBorderColor);
// This needs to be optimized.
// Calculating background brightness again and again is
// a waste of time!!!. Just calculate it only once.
// .....somehow!!!
PRUint8 red = NS_GET_R(aBackgroundColor);
PRUint8 green = NS_GET_G(aBackgroundColor);
PRUint8 blue = NS_GET_B(aBackgroundColor);
PRUint8 elementBrightness = NS_GetBrightness(rb,gb,bb);
PRUint8 backgroundBrightness = NS_GetBrightness(red, green, blue);
if (backgroundBrightness < COLOR_DARK_THRESHOLD) {
f0 = COLOR_DARK_BS_FACTOR;
f1 = COLOR_DARK_TS_FACTOR;
if(elementBrightness == MAX_DARKNESS)
{
rb = NS_GET_R(DARK_GRAY);
gb = NS_GET_G(DARK_GRAY);
bb = NS_GET_B(DARK_GRAY);
}
}else if (backgroundBrightness > COLOR_LIGHT_THRESHOLD) {
f0 = COLOR_LITE_BS_FACTOR;
f1 = COLOR_LITE_TS_FACTOR;
if(elementBrightness == MAX_BRIGHTNESS)
{
rb = NS_GET_R(LIGHT_GRAY);
gb = NS_GET_G(LIGHT_GRAY);
bb = NS_GET_B(LIGHT_GRAY);
}
}else {
f0 = COLOR_DARK_BS_FACTOR +
(backgroundBrightness *
(COLOR_LITE_BS_FACTOR - COLOR_DARK_BS_FACTOR) / MAX_COLOR);
f1 = COLOR_DARK_TS_FACTOR +
(backgroundBrightness *
(COLOR_LITE_TS_FACTOR - COLOR_DARK_TS_FACTOR) / MAX_COLOR);
}
r = rb - (f0 * rb / 100);
g = gb - (f0 * gb / 100);
b = bb - (f0 * bb / 100);
aResult[0] = NS_RGB(r, g, b);
r = rb + (f1 * (MAX_COLOR - rb) / 100);
g = gb + (f1 * (MAX_COLOR - gb) / 100);
b = bb + (f1 * (MAX_COLOR - bb) / 100);
aResult[1] = NS_RGB(r, g, b);
}
int NS_GetBrightness(PRUint8 aRed, PRUint8 aGreen, PRUint8 aBlue)
{
PRUint8 intensity = (aRed + aGreen + aBlue) / 3;
PRUint8 luminosity =
((RED_LUMINOSITY * aRed) / 100) +
((GREEN_LUMINOSITY * aGreen) / 100) +
((BLUE_LUMINOSITY * aBlue) / 100);
return ((intensity * INTENSITY_FACTOR) +
(luminosity * LUMINOSITY_FACTOR)) / 100;
}
// 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,PRUint16 &aHue,PRUint16 &aSat,PRUint16 &aValue)
{
PRUint8 r,g,b;
PRInt16 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 = (PRUint16)hue;
}
// 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,PRUint16 aHue,PRUint16 aSat,PRUint16 aValue)
{
PRUint16 r=0,g=0,b=0;
PRUint16 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 = (PRUint16) 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 = (PRUint16)(percent*(255-aSat));
q = (PRUint16)(percent*(255-(aSat*f)));
t = (PRUint16)(percent*(255-(aSat*(1.0-f))));
// i is guarenteed 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_RGB(r,g,b);
}