Re: Problem with thumbnail mamagement for image files

["Dr. Michael J. Chudobiak" <mjc avtechpulse com>]

> I have brought this to the attention of the gThumb developers and they
> suggested bringing this request to this list since the standard detect
> algorithm is:
>
> 	if (file.mtime != thumb.MTime) {
> 	    recreate_thumbnail ();
> 	}

The 1-second granularity of mtime causes trouble when a file is being 
created slowly in chunks - for instance, when a RS232-connected scanner 
or a device like an oscilloscope is saving images to disk.

For example, gnome may try to thumbnail the incomplete file at t=10.1 
seconds, and create a "failed" thumbnail associated with that 
filename+mtime. The device may then save the final bit of the file at 
t=10.4 seconds, but apps will still use the failed thumbnail.

gThumb ignores failed thumbnails (and attempts to re-thumbnail) if the 
mtime is within the last 5 seconds to avoid this problem (because I 
really do use gthumb with my oscilloscope...)

Anyway... some of these odd problems could be avoided if the 
original-file-size was also saved (as a png text chunk) along with the 
mtime, and both the mtime and the file size were checked. (This would be 
backward compatible - new apps would use the original-file-size check if 
the thumbnail had the original-file-size encoded.)

Is there any hope of changing the thumbnailing spec?

- Mike