[Tilesathome] Lowzoom Place Labels displaced

[Sebastian Spaeth]

Matthias Julius wrote:
> Sebastian Spaeth <Sebastian at SSpaeth.de> writes:
> 
>> Yes. If we did proper projection, we could cut the number of inkscape 
>> calls by a factor of 10. Cutting a full zoom level inkscape in 256x256 
>> tiles rather than doing one y-stripe at a time would be beneficial (from 
>> a render time perspective)
> 
> I was wondering about that, too.  For the 6th zoom level of a tileset
> (z17 usually) this creates 8192 x 8192 pixel image which would be 256
> MB of raw RGBA data for transparent layers.  Do you think the tile
> splitter would digest that well?

The tile splitter has no problem with that. It's rather inkscape 
crapping out with these sizes and complex tiles. But then as inkscape 
seems to load and render the complete svg anyway even if we are only 
interested in a small stripe, it wouldn't make a different memory wise 
to what we have now.

But generally doing striped calls should be what we do on complex 
tilesets, while easier ones can be rendered in one go. I had a local 
modification (which might still be around) which showed that the render 
time was proportional to the number of times we called inkscape. So this 
would translate in *real* savings.

One needs to modify the SplitImageX routing to cope with multi-stripe 
images.

However, I stopped my experiments when it showed that z17 tiles were 
moved about 1 tile when doing it in one go. I just don't know enough 
about projections and the osmarender parallellogram approach to fix 
these things.

spaetz