gdk pixbuf Viewer for RAW preview images and Gnome EOG/EOM EXIF rating plugins

This project provides 3x plugins:

• a gdk pixbuf loader that handles RAW files (primarily Nikon NEF, Canon CR2 and DNGs) that loads the largest embedded preview image available (via exiv2) - the RAW file support is dependant on exiv2. The largest embedded preview image is dependant on the underlying device but the user can choose to scale for easier handling by gsettings set org.gtk.gdk-pixbuf.exiv2-rawpreview scale-limit 1632. Set G_MESSAGES_DEBUG=gdk-pixbuf.exiv2-rawpreview to examine values as pixbuf runs.

The available controls, as seen via for i in $(gsettings list-keys org.gtk.gdk-pixbuf.exiv2-rawpreview); do echo "'$i' $(gsettings describe org.gtk.gdk-pixbuf.exiv2-rawpreview $i)"; done:

• scale-limit - scaling of preview image to display
• convert-srgb - attempt to convert colourspace to sRGB
• auto-orientate - disable/enable correct image orientation; you may want this to be false and allow image viewers to auto orientate to avoid double rotation
• annotation-font - font for overlayed EXIF (names as recognised by ImageMagick, see: convert -list font)
• annotation-percent-height - size of overlayed EXIF details based on height (set to 0 to disable and to use explicit font-size)
• `annotation-font-size - font size for EXIF
• 2x Linux desktop image viewer plugins that can set/unset EXIF/XMP rating via the R keybinding - relies on exiv2 for supported EXIF images:
  • Eye of Gnome (eog)
  • Eye of Mate (eom)

Intended Usage

For use when reviewing and making first cut selections from RAW files from within a Linux graphical environment: a precursor ahead of editting your RAW files where a faster lightweight workflow is required (no need for a VM with CaptureNX or Lightroom etc or native Linux RawTherapee etc).

The scale-limit is meant to help optimise needless scaling of images: if you have a 36 megapixel RAW image it may have a small number of embedded preview images of varying and increasing sizes, which is what Nikon cameras tend to do: a Nikon RAW file may embed preview images of 570x, 1632x and full (36mp) 7360x. If your screen is only 1600 pixels wide, there may be no point in using the 36mp preview image that is then scaled to fit screen. In such an situation where you are working with a known size of embedded preview image sizes, you can set scale-limit to the desired size to avoid potential needless image scaling for display.

Setting/Unsetting EXIF/XMP Rating

Using eog or eom, open any files and use r key to toggle rating on the current image file - the rating is only saved when moving away from the current image; if you toggle multiple times that leaves the file in the original rated state, no rating update is written to the file.

Ratings are represented in the XMP Rating tag with a value of 5. Use exiv2 -px foo.NEF to validate rating flag is set on the file.

Current rating is displayed on the bottom right of the statusbar.

Dependancies

Uses gdk-pixbuf, exiv2 and Image Magick. By default the build scripts will try to build all plugins if development dependenacies are satisfied.