====Unixscripts:Photos====

These are useful in manipulating photos (jpegs). They depend on my library **argp.sh**(1) - see [[unixscripts:0-intro|Unix Scripts]] - and these external packages are required **jhead**(1), **jpgtrans**(1), netpbm-progs (**pnmscale**(1)), libjpeg (**djpeg**(1), **cjpeg**(1))
===erect-jpeg===
{{scripts:erect-jpeg | erect-jpeg }} - rotate a photo so that it displays correctly by examining the Orientation Exim information in the file. Uses **xargs**(1) to parallelise operations to as many CPUs as it can find.
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{{page>usages:erect-jpeg&inline}}
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===label-photos===
{{scripts:label-photos | label-photos }} - view *.jpg files and prompts for a label for each, putting the label into the Exif comment field. It also recurses through any directories called ''zoom'', applying the same label to photos of the same name.
++++ usage for label-photos |
{{page>usages:label-photos&inline}}
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===rename-jpeg-by-date===
{{scripts:rename-jpeg-by-date | rename-jpeg-by-date }} - renames jpg files according to the date reported by jhead
++++ usage for rename-jpeg-by-date |
{{page>usages:rename-jpeg-by-date&inline}}
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=== resize-jpeg ===
{{scripts: resize-jpeg| resize-jpeg }} - size a jpeg so that the longest side is the required number of pixels and the other side is scaled.
++++ usage for resize-jpeg |
{{page>usages:resize-jpeg&inline}}
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=== shrink-jpeg ===
{{scripts:shrink-jpeg| shrink-jpeg }} - passes photos through **djpeg**(1) and **cjpeg**(1) which can result in a size reduction of about 50% without compromising much on quality. The amount of shrinkage depends on the camera, of course.
++++ usage for shrink-jpeg |
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