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imageprocessing:imagemagick [2013/07/04 08:45] (current)
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 +====== ImageMagick Tricks and Snippets ======
 +===== create a stack of images =====
 +e.g. all images named inputimage01.tif .. inputimage99.tif in one folder should be converted to one image-stack
 +  convert -adjoin inputimage*.tif outputimage.tif
 +"​-adjoin"​ is optional, if outputimage-format can contain multiple images
 +===== resize image =====
 +- percentage
 +  mogrify -resize 50% image.jpg
 +- to maximal size (all images in current folder)
 +  mogrify -resize 256x256 *.jpg
 +- resize and change bit-depth
 +  mogrify -resize 2994x2994 -depth 8 *.tif
 +===== shave image =====
 +shave off at the image edges to leave away unnecessary parts
 +  mogrify -shave <​width>​x<​height>​ *.tif
 +===== crop image =====
 +==== central crop ====
 +  mogrify -gravity Center -crop 50x80%+0+0 ​ *
 +crops image  to 50% of width and 80% of height
 +==== very small ====
 +  mogrify -shave 1750x250 -chop 450x0 -crop +0-250 +repage *
 +modifies image {{:​imageprocessing:​imagemagick1.jpg?​75|}} into smaller, cropped image {{:​imageprocessing:​imagemagick2.jpg?​29}} (rescaled for illustration purposes)
 +  "​-shave 1750x250"​
 +shaves 1750px left/right and 250 pixel on the top/bottom
 +  "-chop 450x0"
 +chops off 450 pixel on the left side
 +  "-crop +0-250 +repage"​
 +chops off 250 pixel at the bottom side and repages the canvas of the image.
  
 +all info is taken from [[http://​www.imagemagick.org/​Usage/​crop/​|the IM help]]
 +===== convert =====
 +all images in folder from png to jpg
 +  mogrify -format jpg *.png
 +all images in folder from jpg to eps
 +  mogrify -format eps *.jpg
 +create a movie out of still images
 +  convert *.jpg movie.mpg
 +===== create a listing =====
 +to create a listing of the filenames with their size into a textfile use
 +  identify -format "​[\"​%f\",​%w,​%h];​\n"​ *.jpg > listing.txt
 +[via [[http://​groups.google.com/​group/​hugin-ptx/​t/​f4c3467fec4794d7|erik krause]]]
 +===== make a montage of a bunch of images =====
 +Take a directory full of images and make a nice montage, polaroid-style
 +
 +  montage *.tif -bordercolor yellow -background red \\
 +      +polaroid -gravity center -background none -geometry -50-50 polaroid.png
 +
 +{{ :​imageprocessing:​polaroid.jpg?​256 |polaroid.png}}
 +
 +Keep in mind that this only works for not very big amounts of not very big images, so "​resize"​ them first. The resulting image is really big, so you might need to resiye that too...
 +
 +You might also prefer to change the -bordercolor to "​white"​ and the -background to "​black",​ here it is yellow and red for demonstration purposes...
 +
 +  montage *.tif -thumbnail 256x256 -bordercolor yellow -background red +polaroid \\
 +      -gravity center -background green -geometry +1+1 polaroid-green.png
 +
 +{{ :​imageprocessing:​polaroid-green.jpg?​256 |green background}}
 +
 +makes 256x256 -sized thumbnails first and adds a small (1x1) border around each image, so they line up nicely. Substitute "​yellow"​ with "​white",​ "​red"​ with "​black"​ and "​green"​ with "​none"​ to have a useable result...
 +
 +adapted from the [[http://​www.imagemagick.org/​Usage/​montage/#​overlap|ImageMagick help]]