51 lines
1.5 KiB
Text
51 lines
1.5 KiB
Text
hello world plugin
|
|
------------------
|
|
|
|
This is a very simple sample plugin. It is designed to help developers
|
|
see the skeletal basics needed to achieve a functional datasource plugin.
|
|
|
|
Code comments attempt to highlight which code is mandatory, which is
|
|
simply recommended, and which is purely fluff used to get the plugin to
|
|
actually show some data.
|
|
|
|
When added to a map it provides a single point geometry representing
|
|
the center of any query. This means that it should place a point in
|
|
the middle of any map tile and display a "hello world!" label if used like:
|
|
|
|
<?xml version="1.0" encoding="utf-8"?>
|
|
<Map srs="+init=epsg:4326" background-color="white">
|
|
<Style name="style">
|
|
<Rule>
|
|
<PointSymbolizer />
|
|
<TextSymbolizer name="[key]" face_name="DejaVu Sans Book" size="10" dx="5" dy="5"/>
|
|
</Rule>
|
|
</Style>
|
|
<Layer name="test" srs="+init=epsg:4326">
|
|
<StyleName>style</StyleName>
|
|
<Datasource>
|
|
<Parameter name="type">hello</Parameter>
|
|
</Datasource>
|
|
</Layer>
|
|
</Map>
|
|
|
|
|
|
Or used in python like:
|
|
|
|
from mapnik import *
|
|
m = Map(600,400)
|
|
m.background = Color('white')
|
|
s = Style()
|
|
r = Rule()
|
|
r.symbols.append(PointSymbolizer())
|
|
t = TextSymbolizer(Expression("[key]"),"DejaVu Sans Book",10,Color('black'))
|
|
t.displacement = (15,15)
|
|
r.symbols.append(t)
|
|
s.rules.append(r)
|
|
m.append_style('style',s)
|
|
ds = Datasource(type="hello")
|
|
l = Layer('test')
|
|
l.styles.append('style')
|
|
l.datasource = ds
|
|
m.layers.append(l)
|
|
m.zoom_all()
|
|
render_to_file(m,'test.png')
|