USAGE: mottle [-t type ] [-a amount] [-g granularity] [-c color] [-r region] [-n newseed] [-s] infile outfile
USAGE: mottle [-h or -help]

-t .... type ............. type of mottle effect; displace (or d), modulate (or m)
.......................... blend (or b); default=displace
-a .... amount ........... amount of displacement; integer>=0; default=5
-g .... granularity ...... granularity or size of mottled areas; float>=0; default=5
-c .... color ............ mixing color for blend effect; any valid IM color; default=black
-r .... region ........... blend region where color is applied; foreground (or f) or
.......................... background (or b); default=foreground
-n .... newseed .......... forced seed value; integer>0; default will randomly change seed
-s ....................... color shimmer for blend effect

PURPOSE: To apply various mottle effects to an image.

DESCRIPTION: MOTTLE various mottle effects to an image. The effect types are displacement, modulation and blend. The latter two are more suited for for application to binary images.

ARGUMENTS:

-t type ... TYPE of mottle effect. Choices are: displace or (d), modulate (or m) and blend (or b). The modulate and blend options are better suited for binary images. The default is displace.

-a amount ... AMOUNT of displacement in pixels. Values are integers>=0. The default=5. Modulate and blend are not sensitive to this parameter.

-g granularity ... GRANULARITY is the size of the mottled areas. Values are floats>=0. The default=5.

-c color ... COLOR is the mixing color for the type=blend effect. Any valid IM color is allowed. See http://imagemagick.org/script/color.php The default=white. When region=background, this produces a "cloud-like" color effect on a color image. When region=foreground, this produces a mottled color tinting effect to a color image.

-r region ... REGION is the location where the type=blend effect coloration is applied. Values are either foreground (f) or background (b). The default=foreground.

-n newseed ... NEWSEED is the forced seed value to use for randomization. This permits the pattern to be repeated. Values are integers>0. The default is to change the seed value randomly each time the script is run, thus causing somewhat different patterns each time the script is run.

-s ... Apply a color shimmer effect with type=modulate.

CAVEAT: No guarantee that this script will work on all platforms, nor that trapping of inconsistent parameters is complete and foolproof. Use At Your Own Risk.