LEICA BigTIFF

Adam Goode adam at spicenitz.org
Mon Jul 9 13:47:29 EDT 2012


I don't see a problem with exposing all the thumbnails at even these sizes.

On Sat, Jul 7, 2012 at 6:05 PM, Benjamin Gilbert <bgilbert at cs.cmu.edu> wrote:
> On 07/07/2012 12:14 PM, Agelos Pappas wrote:
>> As you can see the one of the two image tags, the thumbnail, has the
>> same dimensions as the collection. The code will fail if the above
>> condition is not met in any of the two tags.
>
> Nice, that's a better solution.
>
>> I'm adding the lowest resolution of the thumbnail as an associated
>> image. I thought it would be quicker to not use the largest one.
>
> In the example slide, our choices are:
> 1616 x 4668
> 404 x 1167
> 101 x 291
>
> The other slide formats have associated images which are 1000-2000
> pixels on their longest side.  I don't like the idea of OpenSlide eating
> data (by returning a downsampled associated image), but returning a 30
> MB buffer is a bit excessive.  Adam, any thoughts?  Associated images
> are demand-loaded these days, so there's no runtime overhead if the app
> doesn't request them.
>
>> There is a big issue with libxml2 however, which I found out the hard
>> way. There's a function called *xmlCleanupParser*. This function should
>> be called once we are done using the library, so that it cleans up
>> memory used by the library itself.
> [...]
>> Does this mean that whenever you call the library's functions, new
>> memory is allocated? Or does initialization takes place only once?
>
> Initialization takes place only once.  I agree with Adam, it's not safe
> for us to call xmlCleanupParser at all.  Also, xmlInitParser is not
> thread-safe, so we need to call it ourselves from _openslide_init rather
> than letting libxml2 call it implicitly.
>
>> Let me know if you want me to send you the leica vendor file I've written.
>
> When you're ready, send a GitHub pull request on openslide/openslide and
> I'll review it.
>
> --Benjamin Gilbert
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