2003.10.31 22:40 "[Tiff] col_offset in TIFFRGBAGetImage", by Mark Tigges

Hello group,

I'm experimenting with the TIFFRGBAImageGet function (and it's relatives). Particularly I wish to use it to get a subset of a tiff. It sort of works. In order to specify the width and height of the subset of the tiff that I want I obviously pass in the width and height values to the get function. But if I want to set the origin I have been using the row_offset and col_offset members of the img parameter (a struct _TIFFRGBAImage instance).

This seemed to be working. I'm working on very large images, the results seemed right, so I assumed they were. Unfortunately they weren't. It seems that the col_offset is pretty much ignored. No matter what I ask for, I only get data starting at the 0th column. The documentation of the state structure is kind of sparse. Can anybody fill in the gaps in my understanding?

How do I specify an arbitrary rectangle to grab using the TIFFRGBAImageGet function.

Is there a different method that is the accepted method?

Thanks,

MArk.