Graphviz  2.41.20170921.2350
colorutil.c
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1 /* $Id$Revision: */
2 /* vim:set shiftwidth=4 ts=8: */
3 
4 /*************************************************************************
5  * Copyright (c) 2011 AT&T Intellectual Property
6  * All rights reserved. This program and the accompanying materials
7  * are made available under the terms of the Eclipse Public License v1.0
8  * which accompanies this distribution, and is available at
9  * http://www.eclipse.org/legal/epl-v10.html
10  *
11  * Contributors: See CVS logs. Details at http://www.graphviz.org/
12  *************************************************************************/
13 
14 #include "general.h"
15 #include "colorutil.h"
16 
17 static void r2hex(float r, char *h){
18  /* convert a number in [0,1] to 0 to 255 then to a hex */
19  static char hex[] = "0123456789abcdef";
20  int i = (int)(255*r+0.5);
21  int j = i%16;
22  int k = i/16;
23  h[0] = hex[k];
24  h[1] = hex[j];
25 }
26 
27 void rgb2hex(float r, float g, float b, char *cstring, char *opacity){
28  cstring[0] = '#';
29  r2hex(r, &(cstring[1]));
30  r2hex(g, &(cstring[3]));
31  r2hex(b, &(cstring[5]));
32  //set to semitransparent for multiple sets vis
33  if (opacity && strlen(opacity) >= 2){
34  cstring[7] = opacity[0];
35  cstring[8] = opacity[1];
36  cstring[9]='\0';
37  } else {
38  cstring[7] = '\0';
39  }
40 }
41 
42 real Hue2RGB(real v1, real v2, real H) {
43  if(H < 0.0) H += 1.0;
44  if(H > 1.0) H -= 1.0;
45  if((6.0*H) < 1.0) return (v1 + (v2 - v1) * 6.0 * H);
46  if((2.0*H) < 1.0) return v2;
47  if((3.0*H) < 2.0) return (v1 + (v2 - v1) * ((2.0/3.0) - H) * 6.0);
48  return v1;
49 }
50 
51 char *hex[16]={"0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"};
52 
53 char * hue2rgb(real hue, char *color){
54  real v1, v2, lightness = .5, saturation = 1;
55  int red, blue, green;
56 
57  if(lightness < 0.5)
58  v2 = lightness * (1.0 + saturation);
59  else
60  v2 = (lightness + saturation) - (saturation * lightness);
61 
62  v1 = 2.0 * lightness - v2;
63 
64  red = (int)(255.0 * Hue2RGB(v1, v2, hue + (1.0/3.0)) + 0.5);
65  green = (int)(255.0 * Hue2RGB(v1, v2, hue) + 0.5);
66  blue = (int)(255.0 * Hue2RGB(v1, v2, hue - (1.0/3.0)) + 0.5);
67  color[0] = '#';
68  sprintf(color+1,"%s",hex[red/16]);
69  sprintf(color+2,"%s",hex[red%16]);
70  sprintf(color+3,"%s",hex[green/16]);
71  sprintf(color+4,"%s",hex[green%16]);
72  sprintf(color+5,"%s",hex[blue/16]);
73  sprintf(color+6,"%s",hex[blue%16]);
74  color[7] = '\0';
75  return color;
76 }
77 
78 
79 void hue2rgb_real(real hue, real *color){
80  real v1, v2, lightness = .5, saturation = 1;
81  int red, blue, green;
82 
83  if(lightness < 0.5)
84  v2 = lightness * (1.0 + saturation);
85  else
86  v2 = (lightness + saturation) - (saturation * lightness);
87 
88  v1 = 2.0 * lightness - v2;
89 
90  red = (int)(255.0 * Hue2RGB(v1, v2, hue + (1.0/3.0)) + 0.5);
91  green = (int)(255.0 * Hue2RGB(v1, v2, hue) + 0.5);
92  blue = (int)(255.0 * Hue2RGB(v1, v2, hue - (1.0/3.0)) + 0.5);
93 
94 
95  color[0] = red/255.;
96  color[1] = green/255.;
97  color[2] = blue/255.;
98 
99 }
char * hex[16]
Definition: colorutil.c:51
void rgb2hex(float r, float g, float b, char *cstring, char *opacity)
Definition: colorutil.c:27
char * hue2rgb(real hue, char *color)
Definition: colorutil.c:53
real Hue2RGB(real v1, real v2, real H)
Definition: colorutil.c:42
int
Definition: grammar.c:1264
void hue2rgb_real(real hue, real *color)
Definition: colorutil.c:79
#define real
Definition: general.h:34