Filter-jpegrotate-lossless

filter-jpegrotation-lossless is a plugin for Zenphoto for lossless rotation of JPEG images using jpegtran.

What it does currently:

When importing JPEG images to an album, this filter checks for the EXIFOrientation value and when this value suggests that the image must be rotated, it rotates the image and updates the EXIFOrientation value accordingly, so that the image will not be rotated again.

Requirements:

  • This plugin requires PHP5. It will not work with PHP4.
  • jpegtran executable must be available on the server (http://jpegclub.org/, Debian/Ubuntu: sudo apt-get install libjpeg-progs)
  • put the plugin files (file “filter-jpegrotation-lossless.php” and folder “filter-jpegrotation-lossless” with all it’s contents) into your zenphoto/plugins folder
  • plugin must be enabled
  • in the plugin settings for filter-jpegrotation-lossless you must explicitly enable auto rotation on import, and you must specify the path to jpegtran on your system

Notes:

  • Unlike the traditional auto_rotate feature of Zenphoto, this filter alters the original uploaded image! Normally, this should do no harm because the rotation is lossless and can be repeated without loosing image quality.
  • There is no problem if auto_rotate in Zenphoto is enabled: it simply does nothing if the image is already rotated.

Not yet implemented:

  • Manual lossless rotation of images in the admin/edit interface

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