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June 2006
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2006.06.02 16:35 "Re: TIFFWriteRawStrip with multi-strip?", by Joris Van Damme
Bernie, Pallek, Bernie: #CIPO - OPIC wrote: > I have already-compressed (COMPRESSION_CCITT_T6-type) data which I'd > like to bind to a new TIFF file. So, I'm setting rows-per-strip > equal to the image length (height), and I'm using something like: > > checkCount = TIFFWriteRawStrip(someTifStructInstance, 0, someBuffer, > theSizeOfThatBuffer); > > and this works just fine. > > However, I'd like to now use an arbitrary value for rows-per-strip. > But this means I need to find the byte offsets within 'someBuffer' so > I can call TIFFWriteRawStrip repeatedly, incrementing the strip > number. The crux? Since the data is compressed, how in the crap > will I know where each strip's data begins within 'someBuffer'? Each > strip is going to vary in size. This type of compression, G4, encodes each scanline relative to previous scanline. The first scanline is encoded relative to a 'virtual' all-white line. So if you divide the block, the first part will make sense, the second will be corrupted. There's no way you can work around that. 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