Fred's ImageMagick Scripts



    Licensing:

    My scripts are available free of charge for non-commercial use.

    If you redistribute or incorporate any of these scripts into other free applications, you may use my scripts by simply referencing my name and this web page: Fred Weinhaus and http://www.fmwconcepts.com/imagemagick/index.html

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

    Usage, whether stated in script or not, is also subject to the ImageMagick license, which can be found at: http://www.imagemagick.org/script/license.php

ZOOMBLUR


Applies a radial or zoom blur to an image.

Download Script

last modified: June 02, 2008



USAGE: zoomblur [-z zoom] [-e] infile outfile
USAGE: zoomblur [-h or -help]

-a .... amount ..... amount of zoom blur; float; amount>=1; default=1.2
-e ................. expands the output image by the amount of zoom

PURPOSE: To apply a radial or zoom blur to an image.

DESCRIPTION: ZOOMBLUR applies a radial blur to an image by a process of iterative zooming and blending.

ARGUMENTS:

-a amount ... AMOUNT is the zoom factor. Values are floats greater than or equal to 1. A value of 1 produces no effect. Larger values increase the radial blur. Typical values are between 1 and 1.5. The default is 1.2. Note that the large the amount, the more iterations it will take.

-e ... Expands the output image size by the amount of the zoom.

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.


EXAMPLES


Zoom Blur
http://www.jhlabs.com/ip/blurring.html

Original

Arguments:
-a 1.1

Arguments:
-a 1.2

Arguments:
-a 1.3

Arguments:
-a 1.4



Zoom Blur With vs Without Expand
http://www.jhlabs.com/ip/blurring.html

Original

Arguments:
-a 1.2

Arguments:
-a 1.2 -e



What the script does is as follows:

  • Successively zooms the image by an increasing zoom factor
  • Blends the result with image
  • Repeats for each iteration until the full zoom value is reached

This is equivalent to the following IM commands

  • rad=`convert $infile -format "%[fx:hypot(w/2,h/2)]" info:`
  • zoomfrac=`convert xc: -format "%[fx:($amount-1)]" info:`
  • iter=`convert xc: -format "%[fx:int($zoomfrac*$rad)]" info:`
  • ww=`convert $infile -format "%w" info:`
  • hh=`convert $infile -format "%h" info:`
  • if [ "$expand" = "yes" ]; then
  • ww=`convert $infile -format "%[fx:floor(w*$amount)]" info:`
  • hh=`convert $infile -format "%[fx:floor(h*$amount)]" info:`
  • fi
  • i=1
  • convert $infile $tmpA
  • while [ $i -le $iter ]; do
  • j=`expr $i + 1`
  • new=`convert xc: -format "%[fx:100/$j]" info:`
  • old=`convert xc: -format "%[fx:100-$new]" info:`
  • s=`convert xc: -format "%[fx:1 + $zoomfrac*$i/$iter]" info:`
  • convert $tmpA -resize $s% -gravity center -crop ${ww}x${hh}+0+0 +repage $tmpC
  • composite -blend $old%x$new% -gravity center $tmpA $tmpC $tmpA
  • i=`expr $i + 1`
  • done
  • convert $tmpA $outfile