[PYTHON IMAGE-SIG] Selective reads with PIL

Fredrik Lundh fredrik_lundh@ivab.se
Thu, 11 Jul 1996 21:16:26 +0200

> Now I'm looking ahead to an application that uses PhotoCD images.  I would
> like to be able to read any of the five resolutions from a PhotoCD file.

Unfortunately, Kodak considers the PhotoCD compression method and file
format proper to be strictly proprietary stuff.  I've already
stretched it a little in PIL by supporting the uncompressed base

One solution might be to create a custom plugin using hpcdtoppm the
ImageMagick convert utility.  (A few weeks ago, Zack Roadhouse
(zack@lems.brown.edu) reported that he was working on a tighter
interface to ImageMagick.  Any news on this front?)

> Similar problems arise with other multi-resolution formats and with
> formats that encode multiple images in one file.

To handle multiple resolutions, the next release (0.2, early August)
includes "draft" and "thumbnail" methods that can be used to speed up
decoding where possible.  This currently includes JPEG (1/2, 1/4, 1/8)
and PCD (192x128 and 256x384).

To handle multiple images, seek() and tell() methods will be
implemented (e.g. TIFF, animated GIF).

Regards	/F

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