Yes, I am setting rowsPerStrip myself
unsigned int rowsPerStrip = STRIP_SIZE_DEFAULT /
scanLineSize;
ZTRACE_RUNTIME("Seting TIFFTAG_ROWSPERSTRIP to: %u",
rowsPerStrip);
TIFFSetField(m_tiff, TIFFTAG_ROWSPERSTRIP, rowsPerStrip);
And prewriting the empty encoded strips worked a treat!!
Thanks a lot
From: Olivier Paquet <[email protected]>
Sent: 13 April 2023 14:17
To: David C. Partridge <[email protected]>
Cc: [email protected]
Subject: Re: [Tiff] TIffWriteDirectory() causes problems
I'm not sure where your values come from so I can't say if your rowsPerStrip is
ok but the rest looks right. I would rather read TIFFTAG_ROWSPERSTRIP directly
than try to compute it, unless you're setting it yourself of course.
Compression will not change the number of strips, only their size.
I don't know if you'll still need TIFFWriteDirectory() as I've never done
exactly that. It should be obvious when trying it.
Olivier
Le jeu. 13 avr. 2023, à 08 h 52, David C. Partridge
<[email protected] <mailto:[email protected]> > a écrit
:
So, I just need to add those tags with a number of entries equal to the number
to strips to be written, which I think I can work out like this:
//
// Work out how many scanlines fit into the default strip
//
unsigned int rowsPerStrip = STRIP_SIZE_DEFAULT /
scanLineSize;
//
// From that we derive the number of strips
//
int numStrips = h / rowsPerStrip;
//
// If it wasn't an exact division (IOW there's a
remainder), add one
// for the final (short) strip.
//
if (0 != h % rowsPerStrip)
++numStrips;
is that still valid if compression is enabled?
If I do that, I assume the internal code would update those tags, and I would
then need to call WriteDirectory immediately prior to Close? Or would the
automatic RewriteDirectory do it in place in the size hadn’t changed?
Thanks
David
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