1 #include "mrilib.h"
2
3 /*----- set up an RGB color table, with ngray level of gray,
4 and a color "cube" nrr X ngg X nbb color cells on a side;
5 total number of cells is ngray+nrr*ngg*nbb-1 [05 Oct 2004] -----*/
6
mri_colorsetup(int ngray,int nrr,int ngg,int nbb)7 MRI_IMAGE * mri_colorsetup( int ngray , int nrr , int ngg , int nbb )
8 {
9 MRI_IMAGE *im ;
10 rgbyte *ar ;
11 int rr,gg,bb , nn ;
12 float rac,gac,bac ;
13
14 im = mri_new( ngray + nrr*ngg*nbb - 1 , 1 , MRI_rgb ) ;
15 ar = (rgbyte *) MRI_RGB_PTR(im) ;
16
17 gac = 255.9f / ngray ; nn = 0 ; /* actually, ngray+1 levels */
18 for( gg=0 ; gg <= ngray ; gg++,nn++ ){
19 ar[nn].r = ar[nn].g = ar[nn].b = (byte)(gac*gg) ;
20 }
21
22 rac = 255.9f/(nrr-1) ; gac = 255.9f/(ngg-1) ; bac=255.9f/(nbb-1) ;
23
24 for( bb=0 ; bb < nbb ; bb++ ){ /* skip the all black and */
25 for( gg=0 ; gg < ngg ; gg++ ){ /* the all white colors */
26 for( rr=0 ; rr < nrr ; rr++ ){
27 if( rr==0 && gg==0 && bb==0 ) continue ;
28 if( rr==nrr-1 && gg==ngg-1 && bb==nbb-1 ) continue ;
29 ar[nn].r = (byte)(rac*rr) ;
30 ar[nn].g = (byte)(gac*gg) ;
31 ar[nn].b = (byte)(bac*bb) ; nn++ ;
32 } } }
33
34 return im ;
35 }
36