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Subject: Re: [Tiff] TIFFWriteRawStrip with multi-strip?
Date: Wed, 7 Jun 2006 10:50:46 +0200
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Thread-Topic: [Tiff] TIFFWriteRawStrip with multi-strip?
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Status:   

Pallek, Bernie: #CIPO - OPIC wrote:

> > > 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.

Joris replied:

> > 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.

...not to mention that G4 produces a stream of bits, not bytes, so the boundary
between two strips will not fall on a byte boundary in most cases, and it is even
less likely that it will be regular enough to determine a rows-per-strip number.

					Gerben Vos.

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