I think I have this right in my head, but I just want to check.
A Layer can have multiple Styles.
A Style can have multiple Rules.
When processing a Layer, all Styles that apply (based on the rules) and
drawn.
When processing a Style, the first Rule that applies is used.
Is this correct? So when I look at the osm-template.xml file, I see
(with some simplification)
<Layer name="tunnels">
<StyleName>tunnels-casing</StyleName>
<StyleName>tunnels-fill</StyleName>
</Layer>
<Style name="tunnels-casing">
<Rule>
<Filter>([highway] = 'motorway' or [highway]='motorway_link') and
([tunnel] = 'yes' or [tunnel] ='true')</Filter>
<MaxScaleDenominator>200000</MaxScaleDenominator>
<MinScaleDenominator>100000</MinScaleDenominator>
<CssParameter name="stroke-width">3</CssParameter>
</Rule>
</Style>
<Style name="tunnels-fill">
<Rule>
<Filter>([highway] = 'motorway' or [highway]='motorway_link') and
([tunnel] = 'yes' or [tunnel] ='true')</Filter>
<MaxScaleDenominator>200000</MaxScaleDenominator>
<MinScaleDenominator>100000</MinScaleDenominator>
<CssParameter name="stroke-width">2</CssParameter>
</Rule>
</Style>
So, a feature that is at scale of (say) 50000 with the right conditions
based on the filter would be drawn twice. Once with a stroke width of 3
(the tunnels-casing style) and once with a stroke width of 2 (the
tunnels-fill style). And they will be drawn in the order defined by the
Layer tag?
Do I have this all straight?
- Brian
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