Notes about ImageMagick

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  • conversion from multiple images to compressed PDF in A4 format
convert -format A4 -compress <compression> -adjoin *.jpg output.pdf

where:

<compression> = Zip or Group4
  • conversion from image to PDF with rotation
convert -rotate <degrees> input.jpg output.pdf
  • conversion from image to PDF with defined print area
convert -units PixelsPerInch -density <density> -geometry <geometry> -adjoin input.jpg output.pdf

where:

<geometry> = the resolution required for the pdf file
<density> = value in dot/inch
Will define the print area. To get a PDF printable on A4 format (21cmx29.7cm), density should be calculated with respect to -geometry option
E.g.: -geometry 2048x1280
=> density(width) = 2048pixel / 21cm * 2.54cm/inch = 248 pixel/inch
=> density(height) = 1280pixel / 29.7cm * 2.54cm/inch = 109 pixel/inch
=> The resulting command will be:
convert -units PixelsPerInch -density 248x109 -geometry 2048x1280 input.jpg output.pdf

note: you don't need to multiply by 2.54cm/inch when using -units PixelsPerCentimeter

  • to get information from an image file
identify -verbose img.jpg
  • create one image composed from 4 images
montage -frame 5 -geometry +0+0 img1.png img2.png img3.png img4.png result.png
Result will be:
 -------------
| img1 | img2 |
 -------------
| img3 | img4 |
 -------------
montage -tile 3x2 -frame 5 -geometry +0+0 img1.png img2.png img3.png img4.png result.png
Result will be:
 --------------------
| img1 | img2 | img3 |
 --------------------
| img4 |             |
 --------------------
More about montage command: http://www.imagemagick.org/Usage/montage/
  • crop image
convert -crop WxH+Wo+Ho +repage source.jpg destination.jpg

with:

  • W: width of cropped image
  • H: height of cropped image
  • Wo: width offset from upper/left corner of source.jpg
  • Ho: height offset from upper/left corner of source.jpg
More about crop command: http://www.imagemagick.org/Usage/crop/