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November 1999
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1999.11.19 10:16 "Re: multiple tiff files", by Peter Zitzelsperger
Hi!
First of all, thanks to your comment.
Ledoux wrote:
> If your purpose is to save multiple images in the same tiff file , the
> exact term is multipage tiff, I can assure that the libtiff supports it
> without any problem , provided that you ONLY use the libtif functions to
> read or write tiles.
>
Yes, I want to create a multipage tiff, and I use *ONLY* libtiff functions.
> >
> > // open tiff file with TIFFOpen(...)
> >
>
> Do you open file in mapped "w" mode or unmapped "wu" mode ? Just a question
> normally it shouldn't affect the file.
Open parameter is ''w''
> >
> > // over all images
> > for( i4_image_count=0;
> > i4_image_count<m_pt_image->GetNumImages(); i4_image_count++ )
> > {
> > TIFFSetDirectory( tiff_file, i4_image_count );
> >
> > // set some basic tifftags like imagelength, imagewidth,
> > samplesperpixel, bitspersample,...
>
> > // write the data in tiles
> > m_pt_image->WriteBuffer2Tiles( tiff_file,
> > m_pt_image->GetImageLength(
> > i4_image_count ),
> > m_pt_image->GetImageWidth(
> > i4_image_count ),
> > i4_image_count );
>
> What is your WriteBuffer2Tiles method doing ? does it call TIFFWriteTiles
> or any other IO function to write to the file?
WriteBuffer2Tiles does nothing but calculate tiles from strips and writing the
tiles with TIFFWriteTile() from the libtiff. I had long debug sessions to find
that a _TIFFmalloc() in TIFFwritebufferSetup() does not what it is supposed to.
Funny enough, the application does everything correctly when I step through
with the debugger, but it returns an error and exits, when I run it in one
step. So, in theory, its impossible, to find the mistake. Well, I don't know
how, but I'll continue to search...
> >
> > TIFFWriteDirectory( tiff_file );
> > }
> >
> > This should guarantee, that every image entry has its own specific info
> > and data.The trouble I run into is, that
> > -this loop works well for two images, after that, _TIFFalloc fails
> > to get storage
> > -this loop works well for, say nine images, but the file created
> > file has only two entrys, the second
> > of which has strange values for the tags(samples per pixel,...)
>
> Don't hesitate to contact me if you have any other problem.
Well, here I am. Thanks in advance...
Peter Zitzelsperger.