COLOR MAP

This tutorial covers some some color functions using PHP with Image Magick from the command line.
Change to websafe colors
by mapping colors
to a color map
netscape color cube (use gif map)
<?
$IN="SGglass.jpg";
$MAP="netscape.gif";
$COLORMAP="-map";
$OUT="SGglassNC.jpg";
exec ("/usr/bin/convert $IN $COLORMAP $MAP $OUT");
?> 		ORIGINAL

 COLOR MAP

<?
$IN="SGglass.jpg";
$MAP="netscape.gif";
$COLORMAP="+dither -map";
$OUT="SGglassNCd.jpg";
exec ("/usr/bin/convert $IN $COLORMAP $MAP $OUT");
?> 		ORIGINAL
 COLOR MAP
NO DITHER
<?
$IN="SGfish.jpg";
$COLORMAP="-colors 5";
$OUT="SGfishRC.jpg";
exec ("/usr/bin/convert $IN $COLORMAP $OUT");
?> 		ORIGINAL
 REDUCE COLORS
<?
$IN="SGfish.jpg";
$COLORMAP="+dither -colors 5";
$OUT="SGfishRCD.jpg";
exec ("/usr/bin/convert $IN $COLORMAP $OUT");
?> 		ORIGINAL
 REDUCE COLORS
NO DITHER
<?
$IN="SGfish.jpg";
$COLORMAP="-ordered-dither o4x4";
$OUT="SGglassOD4.jpg";
exec ("/usr/bin/convert $IN $COLORMAP $OUT");
?> 		ORIGINAL
 ORDERED DITHER
PIXEL
<?
$IN="SGfish.jpg";
$COLORMAP="-ordered-dither h4x4o";
$OUT="SGfishODht4.jpg";
exec ("/usr/bin/convert $IN $COLORMAP $OUT");
?>
ORIGINAL
 ORDERED DITHER
HALFTONE ORTHOGONAL
<?
$IN="SGfish.jpg";
$COLORMAP="-ordered-dither h4x4a";
$OUT="SGfishODht4.jpg";
exec ("/usr/bin/convert $IN $COLORMAP $OUT");
?>
ORIGINAL
 ORDERED DITHER
HALFTONE ANGLED
<?
$IN="SGfish.jpg";
$COLORMAP="-ordered-dither checks";
$OUT="SGfishODht4.jpg";
exec ("/usr/bin/convert $IN $COLORMAP $OUT");
?>
ORIGINAL
 ORDERED DITHER
CHECKS
<?
$IN="SGglass.jpg";
$COLORMAP="-monochrome";
$OUT="SGglassBW.jpg";
exec ("/usr/bin/convert $IN $COLORMAP $OUT");
?>
ORIGINAL
 BLACK AND WHITE
<?
$IN="SGind.jpg";
$COLORMAP="-posterize 2";
$OUT="SGindPost.jpg";
exec ("/usr/bin/convert $IN $COLORMAP $OUT");
?>
ORIGINAL
 POSTERIZE
<?
$IN="SGglass.jpg";
$COLORMAP="-colorspace HSB -channel B -separate ";
$OUT="SGglassHSB.jpg";
exec ("/usr/bin/convert $IN $COLORMAP $OUT");
?>
ORIGINAL
 BRIGHT GRAY
<?
$IN="SGglass.jpg";
$COLORMAP="-colorspace YUV -channel R -separate ";
$OUT="SGglassYUV.jpg";
exec ("/usr/bin/convert $IN $COLORMAP $OUT");
?>
ORIGINAL
 DARK GRAY
<?
$IN="SGglass.jpg";
$COLORMAP="-colorspace HSL -channel B -separate ";
$OUT="SGglassHSL.jpg";
exec ("/usr/bin/convert $IN $COLORMAP $OUT");
?>
ORIGINAL
 LIGHT GRAY


Below are a zip of a sample Color Map script plus a Color Map form. There is also a text version of the form if you prefer that to the zip. If you use the text version you will also need a copy of the netscape gif.

COLOR MAP ZIP

COLOR MAP TEXT