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/* $Id$Revision: */
/* vim:set shiftwidth=4 ts=8: */
/*************************************************************************
* Copyright (c) 2011 AT&T Intellectual Property
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors: See CVS logs. Details at http://www.graphviz.org/
*************************************************************************/
#include "general.h"
#include "colorutil.h"
static void r2hex(float r, char *h){
/* convert a number in [0,1] to 0 to 255 then to a hex */
static char hex[] = "0123456789abcdef";
int i = (int)(255*r+0.5);
int j = i%16;
int k = i/16;
h[0] = hex[k];
h[1] = hex[j];
}
void rgb2hex(float r, float g, float b, char *cstring, char *opacity){
cstring[0] = '#';
r2hex(r, &(cstring[1]));
r2hex(g, &(cstring[3]));
r2hex(b, &(cstring[5]));
//set to semitransparent for multiple sets vis
if (opacity && strlen(opacity) >= 2){
cstring[7] = opacity[0];
cstring[8] = opacity[1];
cstring[9]='\0';
} else {
cstring[7] = '\0';
}
}
real Hue2RGB(real v1, real v2, real H) {
if(H < 0.0) H += 1.0;
if(H > 1.0) H -= 1.0;
if((6.0*H) < 1.0) return (v1 + (v2 - v1) * 6.0 * H);
if((2.0*H) < 1.0) return v2;
if((3.0*H) < 2.0) return (v1 + (v2 - v1) * ((2.0/3.0) - H) * 6.0);
return v1;
}
char *hex[16]={"0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"};
char * hue2rgb(real hue, char *color){
real v1, v2, lightness = .5, saturation = 1;
int red, blue, green;
if(lightness < 0.5)
v2 = lightness * (1.0 + saturation);
else
v2 = (lightness + saturation) - (saturation * lightness);
v1 = 2.0 * lightness - v2;
red = (int)(255.0 * Hue2RGB(v1, v2, hue + (1.0/3.0)) + 0.5);
green = (int)(255.0 * Hue2RGB(v1, v2, hue) + 0.5);
blue = (int)(255.0 * Hue2RGB(v1, v2, hue - (1.0/3.0)) + 0.5);
color[0] = '#';
sprintf(color+1,"%s",hex[red/16]);
sprintf(color+2,"%s",hex[red%16]);
sprintf(color+3,"%s",hex[green/16]);
sprintf(color+4,"%s",hex[green%16]);
sprintf(color+5,"%s",hex[blue/16]);
sprintf(color+6,"%s",hex[blue%16]);
color[7] = '\0';
return color;
}
void hue2rgb_real(real hue, real *color){
real v1, v2, lightness = .5, saturation = 1;
int red, blue, green;
if(lightness < 0.5)
v2 = lightness * (1.0 + saturation);
else
v2 = (lightness + saturation) - (saturation * lightness);
v1 = 2.0 * lightness - v2;
red = (int)(255.0 * Hue2RGB(v1, v2, hue + (1.0/3.0)) + 0.5);
green = (int)(255.0 * Hue2RGB(v1, v2, hue) + 0.5);
blue = (int)(255.0 * Hue2RGB(v1, v2, hue - (1.0/3.0)) + 0.5);
color[0] = red/255.;
color[1] = green/255.;
color[2] = blue/255.;
}
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