mapnik/tests/visual_tests/styles/line-offset.xml

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE Map>
<Map background-color="white" srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs">
    <Layer name="layer" srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs">
        <StyleName>My Style</StyleName>
        <Datasource>
            <Parameter name="type">osm</Parameter>
            <Parameter name="file">../data/line-offset.osm</Parameter>
        </Datasource>
    </Layer>

    <Style name="My Style">
        <Rule>
            <LineSymbolizer/>
        </Rule>
        <Rule>
            <Filter>[ref]='1' or [ref]='3'</Filter>
            <TextSymbolizer size="14" fill="#000" spacing="1" placement="line" face-name="DejaVu Sans Book" halo-radius="1" dy="-10" vertical-alignment="middle">'Some Text'</TextSymbolizer>
        </Rule>
        <Rule>
            <Filter>[ref]='2' or [ref]='4'</Filter>
            <TextSymbolizer size="14" fill="#000" spacing="1" placement="line" face-name="DejaVu Sans Book" halo-radius="1" dy="10" vertical-alignment="middle">'Some Text'</TextSymbolizer>
        </Rule>
        <Rule>
            <Filter>[name]!=''</Filter>
            <TextSymbolizer size="10" fill="#000" placement="line" face-name="DejaVu Sans Book" halo-radius="1">[name]</TextSymbolizer>
        </Rule>
    </Style>
</Map>