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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
@@ Line 20: / Line 20: @@
 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

howto/compress_or_resize_images_in_bash.txt · Last modified: 2019/05/30 09:14 by yehuda

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