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howto:compress_or_resize_images_in_bash [2016/11/23 07:38] yehuda created |
howto:compress_or_resize_images_in_bash [2019/05/30 09:14] yehuda |
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| see more options: https://www.imagemagick.org/script/convert.php | see more options: https://www.imagemagick.org/script/convert.php | ||
| + | |||
| + | ====== Resize image to minimal rate ====== | ||
| + | |||
| + | How about using ImageMagick's convertwhich has exactly such a minimal size option, see Image Geometry options?! | ||
| + | |||
| + | Copy & Paste snippet (bash syntax) -- please notice the ^ after the size specification: | ||
| + | <code bash> | ||
| + | for file in *.jpg; do | ||
| + | echo -n Converting ${file}... | ||
| + | convert -resize 180x180^ "$file" "th_$file" | ||
| + | echo done | ||
| + | done | ||
| + | </code> | ||
| + | |||
| + | In addition, if you want to crop the resulting file to a quadratic shape around the center, you can use this script. The SIZE parameter in the first line specifies (surprise, surprise) the final size of the thumbnail. | ||
| + | <code bash> | ||
| + | SIZE=180 | ||
| + | for file in *.jpg; do | ||
| + | echo -n Converting ${file}... | ||
| + | convert -resize ${SIZE}x${SIZE}^ "$file" temp.png | ||
| + | convert -crop $(identify temp.png | awk -F'[ x]' -v SIZE=$SIZE '{ printf "%ux%u+%u+%u", SIZE, SIZE, ($3-SIZE)/2, ($4-SIZE)/2 }') temp.png "th_$file" | ||
| + | echo done | ||
| + | done | ||
| + | rm temp.png | ||
| + | </code> | ||
| + | |||
| + | The script is not very optimized, as it runs two commands (identify and convert -crop) on the thumbnail. But as the thumbnail is only small, I think the speed is reasonable. | ||
| + | |||
| + | from: https://superuser.com/questions/676887/resize-image-to-a-maximum-size-on-command-line | ||
