Fred's ImageMagick Scripts


    Copyright © Fred Weinhaus

    My scripts are available free of charge for non-commercial (non-profit) use, ONLY.

    For use of my scripts in commercial (for-profit) environments or non-free applications, please contact me (Fred Weinhaus) for licensing arrangements. My email address is fmw at alink dot net.

    If you: 1) redistribute, 2) incorporate any of these scripts into other free applications or 3) reprogram them in another scripting language, then you must contact me for permission, especially if the result might be used in a commercial or for-profit environment.

    Usage, whether stated or not in the script, is restricted to the above licensing arrangements. It is also subject, in a subordinate manner, to the ImageMagick license, which can be found at:

    Please read the Pointers For Use on my home page to properly install and customize my scripts.


Applies a frosted glass effect to an image.

Download Script

last modified: December 15, 2018

USAGE: frosted [-s spread] [-b bluramt] [-r reseed] infile outfile
USAGE: frosted [-h or -help]

-s .... spread ..... spread distance of dispersion; integer>=0; default=5
-b .... bluramt .... amount to blur image before dispersion; integer>=0; default=5
-r .... reseed ..... forced seed value; integer>0; default will randomly change seed

PURPOSE: To apply a frosted glass effect to an image.

DESCRIPTION: FROSTED applies a frosted glass effect to an image by using a sinusoidally modulaated random displacement map.


-s spread ... SPREAD distance of dispersion. Values are integers>=0. Typical values range from 2 to 20. The default=5

-b bluramt ... BLURAMT is the amount of blurring of the image in pixels before applying the dispersion. Values are integers>=0. The default=5.

-r reseed ... RESEED is the forced seed value to use for randomization. This permits the pattern to be repeated. 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.

NOTE: For IM prior to 6.4.8-5, the script uses -fx and may be a little slow.

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.


Example 1


-b 3 -s 3 -r 100

Example 2


-b 5 -s 5 -r 100

What the script does is as follows:

  • Blurs the image
  • Creates a random displacement map
  • Applies the displacement map to the image using a sinusoidal function

This is equivalent to the following IM commands

  • ww=`convert $infile -format "%[fx:w]" info:`
  • hh=`convert $infile -format "%[fx:h]" info:`
  • density=10
  • convert $infile -blur 0x${bluramt} $infile`
  • convert -size ${ww}x${hh} xc: +noise Random -virtual-pixel tile \
    -fx intensity -contrast-stretch 0% $tmp0
  • convert $infile $tmp0 -monitor \
    -fx "xx=i+$spread*sin($density*v*2*pi); yy=j+$spread*cos($density*v*2*pi); u.p{xx,yy}" \