2004.12.07 11:32 "Re: [Tiff] Fetching pixel data from 4bit tiff", by Joris Van Damme

Hi. I'm new to libtiff and I'm no C guru either, so please excuse my ignorance here.

Using LibTiffDelphi?

I am trying to get pixel data from a 4bit TIFF. I can use TIFFReadRGBAImage, TIFFReadR, TIFFReadG, TIFFReadB, TIFFReadA but surely these will not provide the correct data for a 4bit image?

Oh but yes, it should. TIFFReadRGBAImage always returns 32bit RGBA data, regardless of source colorspace and bitdepth. (Which is its greatest drawback, and its greatest convinience.)

You might find more detail here:

http://www.remotesensing.org/libtiff/libtiff.html#TIFFRGBAImage
http://www.remotesensing.org/libtiff/man/TIFFReadRGBAImage.3t.html

Joris Van Damme
info@awaresystems.be
http://www.awaresystems.be
Download your free TIFF tag viewer for windows here:
http://www.awaresystems.be/imaging/tiff/astifftagviewer.html