2008.04.16 14:55 "Re: [Tiff] efficient thumbnailing", by Seth Price

I would like to say that I've just been having the exact same problem, except I've been using ImageMagick and GDAL. The images I'm working with are 14400x14400px.

Any solutions out there?
~Seth

On Apr 16, 2008, at 7:26 AM, Dr. Michael J. Chudobiak wrote:

Is there an efficient way to generate thumbnails from tiff files?

Currently, when the gnome/gtk+ gdk-pixbuf tiff loader wants to generate a thumbnail of a tiff file, it loads the entire image, and

> then scales it. (See http://svn.gnome.org/viewvc/gtk%2B/trunk/gdk-pixbuf/io-tiff.c?view=markup) >.

This uses a lot of memory, and the gtk+ scale-down routines are not very good (http://bugzilla.gnome.org/show_bug.cgi?id=80925).

Is there a way in libtiff to do some scale-while-loading, or prescaling, to reduce memory usage and speed things up? (Or could it be added to libtiff?)

The jpeg loader uses some fast-scaling trickery to scale down by a factor of 2, 4, or 8 first (http://sylvana.net/jpegcrop/djpeg) - I was wondering if there is a tiff equivalent.

Suggestions and pointers to existing code appreciated!