[Tilesathome] Osmarender colours and stylesheets

[Jiri Klement]

>>> This is a problem.  Does that also mean that each z17 .svg file
>>> contains all the icons even if none are used in this tileset?  Then
>>> we have that problem already.
>>

I don't think this is a problem. I've tried to remove all unused paths
from svg and it had virtually no influence on rendering performance. I
suppose it's the same for unused symbols.

> Yes, I noticed that as styles are concerned pixels don't have the same
> size in each layer so lines have to be specified with different widths
> to get the same result.  It certainly would make designing render
> styles easier if that wasn't the case.
>
> Can a scaling factor be specified when including an SVG image in
> another?

Yes it is possible to specify scaling factor. But it should be even
possible to make symbol the same size for all zooms without specifing
scaling factor.

I'm a bit confused about how some symbols are specified in rendering
rules. For example symbol-roundabout_left in zooms 16 and 17.

Its defineded as:

16:
<svg:symbol id="symbol-roundabout_left" viewBox="253.5 253.5 507 507">
// the same as zoom 17
</svg:symbol>
17:
<svg:symbol id="symbol-roundabout_left" viewBox="0 0 507 507">
// the same as zoom 16
</svg:symbol>

and used:
16:
<symbol xlink:href="#symbol-roundabout_left" width="4px" height="4px"
transform="translate(0,0)"/>
17:
<symbol xlink:href="#symbol-roundabout_left" width="2px" height="2px"
transform="translate(-1,-1)"/>

I'ts slightly different but the result seems to be exactly the same.
It looks like zoom 16 and 17 could share this symbol.


If I understand the rendering rules correctly and symbols could be
shared between zoom levels, then it might be could start to move all
symbols to external file shared by all zoom levels. t at h client is
already modifying rules files to include bounding box, so it would be
just a little change to include file with symbols as well.


The next step might be rendering rules for all zoom levels in one
file. So for example airport rendering will look like this:
<symbol xlink:href="#airport" minZoom=12 maxZoom=13/>
<area class="airport" minZoom=14 maxZoom=17/>