2008.01.16 23:23 "Re: [Tiff] Q: TIFFWriteRawTile()", by Frank Warmerdam

Hallo Everybody,

I'm not really sure, that I understood that's right. Is ist really not possible, to change / add some tiles to tiled tiffimage later? I mean, after tile was already once written and / or tiffimage was already closed?

If it's so, why is it so? If itsn't so, how can i change tile later. I tried it, but there were no changes in the image.

Tim,

What version of libtiff are you using?

Looking in the code I see that TIFFWriteRawTile() skips a bunch of stuff that is done by TIFFWriteEncodedTile() that might be important for rewriting tiles such as this:

        if( td->td_stripbytecount[tile] > 0 )
         {
            /* Force TIFFAppendToStrip() to consider placing data at end
                of file. */
             tif->tif_curoff = 0;
         }

I never use the "Raw" interfaces so it is entirely possible they are not functioning properly with regard to some of the update-in-place logic. But - in theory - it is intended that what you want should work if you open a file in update mode.

Best regards,
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