GNOME Bugzilla – Bug 158190
add thumbnail loader for JPEG images
Last modified: 2004-12-22 21:47:04 UTC
A recent addition to the GIMP 2.2 API allows plug-ins to register an additional procedure to give access to a thumbnail embedded in an image file. The JPEG format allows for such thumbnails so it would be nice if the JPEG plug-in would provide this functionality.
See also bug #155761 which is closely related and should best be addressed at the same time.
Created attachment 33823 [details] [review] Patch for this This patch works fine. It is much faster than the full preview already. It /can/ be speedened up (to be zippy) if there is some way to read the size of the image from the EXIF in a standard way (not a camera-specific way). But you can apply this one now. - Mukund
Actually I would like to only apply this change if we also make sure that the thumbnail in the EXIF data is correctly changed when we save a JPEG file. Otherwise this nice change will cause GIMP to show invalid thumbnail previews for JPEG files that have been changed using GIMP (see bug #155761).
Sven, question about this: Currently the EXIF data is loaded as a parasite (atleast by the JPEG plug-in). I can't find any other plug-ins which load EXIF data, but they could technically get this feature at a later date. Now who has the job of recomputing this thumbnail? Is it the app which does this before calling the save plug-in? Or is it the plug-in itself? Cause the EXIF data can be theoretically shared among different file formats. The way I understand this, we need to have some sort of API to handle EXIF data for an image, or have the same parasite name and data form ("exif-data") and have the app modify the thumbnail in that before calling the save plug-in.
The GIMP core doesn't know anything about EXIF and is not supposed to do. It's the job of the JPEG plug-in to modify the EXIF thumbnail. It can retrieve the thumbnail from the core. See my comments to #155761 which is where we should continue this discussion.
The patch above has been superceded by the one in bug #155761
Fixed in CVS: 2004-11-17 Michael Natterer <mitch@gimp.org> * plug-ins/common/jpeg.c: applied (modified) patch from S. Mukund which adds EXIF thumbnail loading and saving. Fixes bugs #155761 and #158190.