[Tilesathome] Overall Steps for T at H Client?

[J.D. Schmidt]

Ian Dees skrev:
> On Wed, Sep 24, 2008 at 4:08 PM, Matthias Julius <lists at julius-net.net>wrote:
> 
>> After the tiles are created their appearance does not change anymore
>> significantly.  They are reduced to 256 colors and their compression
>> is optimized.
>>
> 
> Sorry, I should have been clearer. I meant to ask what happens to the OSM
> data once it gets downloaded. For example, I know that some layers have
> "closeareas" run on them. Are there other, similar data modifications done?
> 
Current methodology used by the perl T at H client:
Data is downloaded, data is checked for UTF-8 errors and the 
preprocessors as listed in layers.conf are run on the original 
downloaded data to generate the input data for the rendering of the 
different layers.

Current preprocessors are close-areas and maplint.
Close-areas are run on tile and captionless layers
Maplint is run on maplint layers.

After the preprocessors are run, beziercurvehinting takes place via the 
Lines2curves.pl processor, and then Or/p generates the SVG data files 
for each zoomlevel.

The SVG datafiles are then read by the chosen rendering engine, 
currently Inkscape or Batik, which renders it into glorious technicolor 
bitmap files in PNG format.

These PNG files are then postprocessed by pngqc (tiles, captionless 
layers) or PNGCrush/Optipng (maplint layer) to reduce their phyiscal 
footprint, before being collected into an archive and uploaded to the 
server.
The last part will change soon into a specified tileset file format.

That should about cover it in broad terms.

Dutch

Besides that the beziercurvehinting algorithm is run on tile and 
captionless layers.