A Bash script for resizing all the images in a directory with ImageMagick.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| #!/usr/bin/env bash | |
| # | |
| # Resize all the images in a specified folder with ImageMagick. Put the | |
| # resized images in another specified folder. | |
| # | |
| # Of course, this script is an overkill. Just typing the loop on the command | |
| # line would be enough... | |
| # | |
| # Daniel Weibel <danielmweibel@gmail.com>, 27 Dec. 2014 | |
| #------------------------------------------------------------------------------# | |
| set -e | |
| # Default values | |
| resize=50% | |
| ext=jpg | |
| usage() { | |
| echo "USAGE" | |
| echo " $(basename $0) -i dir -o dir [-r resizing] [-e extension]" | |
| echo | |
| echo "DESCRIPTION" | |
| echo " Resize all images in a directory. Requires ImageMagick." | |
| echo | |
| echo "OPTIONS [DEFAULT]" | |
| echo " -i: Directory containing images to resize" | |
| echo " -o: Output directory" | |
| echo " -r: Resize specification (ImageMagick syntax) [50%]" | |
| echo " -e: File extension of images in input directory [jpg]" | |
| } | |
| [[ "$1" = -h ]] && { usage; exit; } | |
| [[ $(which convert) = "" ]] && \ | |
| { echo "Error: ImageMagick not installed"; exit 1; } | |
| while getopts ":i:o:r:e:" opt; do | |
| case $opt in | |
| i) idir=${OPTARG%/}; ;; # Remove trailing slash if present | |
| o) odir=${OPTARG%/}; ;; # Remove trailing slash if present | |
| r) resize=$OPTARG; ;; | |
| e) ext=$OPTARG; ;; | |
| \?) echo "Error: invalid option: -$OPTARG"; exit 1 ;; | |
| :) echo "Error: option -$OPTARG requires an argument"; exit 1 ;; | |
| esac | |
| done | |
| [[ -z "$idir" ]] && { echo "Error: Must specify input directory"; exit 1; } | |
| [[ -z "$odir" ]] && { echo "Error: Must specify output directory"; exit 1; } | |
| # nullglob: if *.jpg doesn't match any files, glob is replaced by "" not "*.jpg" | |
| # nullglob should always be unset, so we activate it only in a subshell ($()) | |
| [[ $(shopt -s nullglob; echo "$idir"/*.$ext) = "" ]] \ | |
| && { echo "Error: No files with extension $ext in directory $idir"; exit 1; } | |
| for image in "$idir"/*.$ext; do | |
| echo -n "Resizing ${image##*/}... " | |
| # ImageMagick call | |
| convert "$image" \ | |
| -colorspace RGB \ | |
| -resize $resize \ | |
| -colorspace sRGB \ | |
| "$odir"/$(basename "$image") | |
| # 1. Convert colorspace to linear (remove Gamma correction) | |
| # 2. Resize image | |
| # 3. Convert colorspace back to non-linear (add Gamma correction) | |
| # Note: don't use -quality, because an appropriate quality (compression) is | |
| # determined automatically for every image. | |
| echo Done | |
| done |