GNOME Bugzilla – Bug 577499
DNG images show as thumbnails, not the real image.
Last modified: 2018-05-22 13:09:53 UTC
Please describe the problem: The embedded thumbnails, rather than the real images, in DNG files are displayed in apps that use gdk-pixbuf. I believe this is because it's being recognized as a TIFF image. Steps to reproduce: 1. Go to www.rawsamples.ch and download the DNG sample for a Leica M8. (It's 10MB, so I'm not attaching it here.) 2. Open it with gthumb. Actual results: The image displayed is 320x240. Expected results: The full, 3920x2638, image should be displayed. Does this happen every time? Yes; this is reproducible. The issue appears in gthumb, eog, and f-spot. I believe the problem is in gdk-pixbuf, since all three apps use it. Other information: Decoding the image to a TIFF with dcraw allows me to view it properly; the image does not appear to have anything wrong with it. $ dcraw -i -v RAW_LEICA_M8.DNG |grep size Thumb size: 320 x 240 Full size: 3920 x 2638 Image size: 3920 x 2638 Output size: 3920 x 2638 If the image is read as a TIFF, the thumbnail size is read: $ tiffinfo RAW_LEICA_M8.DNG 2>/dev/null|grep Width Image Width: 320 Image Length: 240 gdk-pixbuf is displaying what we'd get if we tried to load the DNG as a TIFF. $ tifftopnm RAW_LEICA_M8.DNG 2>/dev/null | head -2 | tail -1 320 240 This was originally reported on the Ubuntu bugtracker: https://bugs.launchpad.net/ubuntu/+source/gdk-pixbuf/+bug/333388
I don't know what image format dng is. But since gdk-pixbuf does not have a loader for it, what result would you expect ? I believe that libopenraw comes with a pixbuf loader for raw images. Not sure how well it works, but its worth a try.
DNG is Digital Negative; it's a standard format for digital camera raw data used by a wide variety of digital cameras. It is an extension of TIFF 6.0, which can be identified by the presence of tag 50706 (DNGVersion). http://en.wikipedia.org/wiki/Digital_Negative_(file_format) From the DNG 1.2.0.0 standard: "The highest-resolution and quality IFD should use NewSubFileType equal to 0. Reduced resolution (or quality) thumbnails or previews, if any, should use NewSubFileType equal to 1 (for a primary preview) or 10001.H (for an alternate preview)." "DNG recommends, but does not require, that the first IFD contain a low-resolution thumbnail, as described in the TIFF-EP specification." It also appears that this is what's going on in the file in question; the first (thumbnail) IFD is being read, and the thumbnail is being shown.
-- GitLab Migration Automatic Message -- This bug has been migrated to GNOME's GitLab instance and has been closed from further activity. You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.gnome.org/GNOME/gdk-pixbuf/issues/20.