[Tilesathome] Osmarender colours and stylesheets

[Jiri Klement]

I've finished support for external files in orp (it's in svn now).
I've also moved symbol-bus from z17 to symbols/bus.svg as an example.
Symbols scaling works as well, but it scales all symbols in
stylesheet, so I will have to modify all symbols in z16 before bus
symbol can be shared between z16 and z17.

If nobody complains I will start moving symbols to external files later.

On Sun, Aug 10, 2008 at 2:32 PM, Jiri Klement <jiri.klement at gmail.com> wrote:
>>> Stylesheets are a bit confusing but it seems that pixels in
>>> stylesheets actually represent rendered pixels. Even if I'm wrong,
>>> global transformation can be defined for svg file so 1 unit = 1
>>> rendered pixel.
>>
>>This is not as used in osmarender.  Line widths get smaller for higher
>>zoom levels, often by factor 0.5 resulting in the same rendered width.
>
> You're right, I got confused by sligtly obfuscated symbol definition before.
>
>>What is a pixel in SVG anyway?
>
> It depends on size of image, viewbox and rendered size. In case of
> osmarender is every svg file big about  878.91*878.91 ((360 / number
> of z12 tiles)*10000). Size of rendered image is 256 for z12, 512 for
> z13, ...
> So 1 rendered px should be:
> 3.42 units for z12
> 1.71 units for z13
>
> I think it is possible to switch to 1 unit = 1 rendered pixel, but it
> would mean to change orp/osmarender to convert all nodes/ways
> coordinates and rewrite all stylesheets.
>
>
>>> Frederik: I think I saw something about this not being implemented in
>>> or/p? If not it shouldn't be too hard to fix, you can probably find
>>> examples of how this used to be done by looking at some fairly old svn
>>> revisions.
>>
>> Yes, there was a bit of code in the SVG that I did not understand and
>> that wasn't obviously used. Maybe one can even produce .svg files that
>> simply href external symbols?
>
> It should be possible as href is just normal URI. Anyway the
> osmarender code is quite simple:
> - get list of all referenced symbols
> - read svg file <symbolsDir>/<nameOfSymbol>.svg
> - extract symbol from svg file (element with address
> svg:svg/svg:defs/svg:symbol)
>