Fred's ImageMagick Scripts



    Licensing:

    Copyright © Fred Weinhaus

    My scripts are available free of charge for non-commercial 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: http://www.imagemagick.org/script/license.php

CROSSPROCESS


Applies a color crossprocessing effect to an image

Download Script

last modified: September 26, 2017



USAGE: crossprocess [-r ramt] [-g gamt] [-b bamt ] [-B bright] [-C contrast] infile outfile
USAGE: crossprocess [-h or -help]

-r ... ramt ....... red sigmoidal-contrast amount; -100<=integer<=100;
................... default=0 (no change)
-g ... gamt ....... green sigmoidal-contrast amount; -100<=integer<=100;
................... default=0 (no change)
-b ... bamt ....... blue sigmoidal-contrast amount; -100<=integer<=100;
................... default=0 (no change)
-B ... bright ..... post process brightness adjust; -100<=integer<=100;
................... default=0 (no change)
-C ... contrast ... post process contrast adjust; -100<=integer<=100;
................... default=0 (no change)

PURPOSE: To apply a color crossprocessing effect to an image.

DESCRIPTION: CROSSPROCESS applies a color crossprocessing effect to an image by adjusting the sigmoidal-contrast of each of the r,g,b channels of the image.

ARGUMENTS:

-r ramt ... RAMT is the red sigmoidal-contrast amount. Values are integers between -100 and 100. The default=0 (no change)

-g gamt ... GAMT is the green sigmoidal-contrast amount. Values are integers between -100 and 100. The default=0 (no change)

-b bamt ... BAMT is the blue sigmoidal-contrast amount. Values are integers between -100 and 100. The default=0 (no change)

-B bright ... BRIGHT is a post process brightness adjust. Values are integers between -100 and 100. The default=0 (no change)

-C contrast ... CONTRAST is a post process contrast adjust. Values are integers between -100 and 100. The default=0 (no change)

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


Example 1

Original Image
(source)

Arguments:
-r -50 -b 50 -B 5 -C 5

 

Arguments:
-r 50



Example 2

Original Image
(source)

Arguments:
-r 50

 

Arguments:
-r 50 -g -50

 

Arguments:
-r -50



Example 3

Original Image

Arguments:
-rm 50

 

Arguments:
-r -50 -B 20 -C -20

 

Arguments:
-r 100 g -25



What the script does is as follows:

  • Applies a sigmoidal contrast adjustment separately to each channel of the image

This is equivalent to the following IM commands:

  • if [ "$ramt" != "0" ]; then
    test=`convert xc: -format "%[fx:sign($ramt)]" info:`
    ramt=`convert xc: -format "%[fx:abs($ramt)/$div]" info:`
    if [ $test -eq -1 ]; then
    convert $infile -channel R +sigmoidal-contrast $ramt,50% +channel $tmpA1
    else
    convert $infile -channel R -sigmoidal-contrast $ramt,50% +channel $tmpA1
    fi
    fi
  • if [ "$gamt" != "0" ]; then
    test=`convert xc: -format "%[fx:sign($gamt)]" info:`
    gamt=`convert xc: -format "%[fx:abs($gamt)/$div]" info:`
    if [ $test -eq -1 ]; then
    convert $infile -channel G +sigmoidal-contrast $gamt,50% +channel $tmpA1
    else
    convert $infile -channel G -sigmoidal-contrast $gamt,50% +channel $tmpA1
    fi
    fi
  • if [ "$bamt" != "0" ]; then
    test=`convert xc: -format "%[fx:sign($bamt)]" info:`
    bamt=`convert xc: -format "%[fx:abs($bamt)/$div]" info:`
    if [ $test -eq -1 ]; then
    convert $infile -channel B +sigmoidal-contrast $bamt,50% +channel $tmpA1
    else
    convert $infile -channel B -sigmoidal-contrast $bamt,50% +channel $tmpA1
    fi
    fi
  • convert $tmpA1 -brightness-contrast ${bright},${contrast} $outfile