Function msAddColorGD

mapraster.c:210–315

/************************************************************************/

int msAddColorGD(mapObj *map, gdImagePtr img, int cmt, int r, int g, int b)
{
  int c; 
  int ct = -1;
  int op = -1;
  long rd, gd, bd, dist;
  long mindist = 3*255*255;  /* init to max poss dist */

  if( gdImageTrueColor( img ) )
      return gdTrueColor( r, g, b );
  
  /*
  ** We want to avoid using a color that matches a transparent background
  ** color exactly.  If this is the case, we will permute the value slightly.
  ** When perterbing greyscale images we try to keep them greyscale, otherwise
  ** we just perterb the red component.
  */
  if( map->outputformat && map->outputformat->transparent 
      && map->imagecolor.red == r 
      && map->imagecolor.green == g 
      && map->imagecolor.blue == b )
  {
      if( r == 0 && g == 0 && b == 0 )
      {
          r = g = b = 1;
      }
      else if( r == g && r == b )
      {
          r = g = b = r-1;
      }
      else if( r == 0 )
      {
          r = 1;
      }
      else
      {
          r = r-1;
      }
  }

  /* 
  ** Find the nearest color in the color table.  If we get an exact match
  ** return it right away.
  */
  for (c = 0; c < img->colorsTotal; c++) {

    if (img->open[c]) {
      op = c; /* Save open slot */
      continue; /* Color not in use */
    }
    
    /* don't try to use the transparent color */
    if (map->outputformat && map->outputformat->transparent 
        && img->red  [c] == map->imagecolor.red
        && img->green[c] == map->imagecolor.green
        && img->blue [c] == map->imagecolor.blue )
        continue;