mapnik markersnapping testcase

marker.png

marker.xml

<Map srs="+init=epsg:3857" background-color="#ffffff">
    <Style name="points" filter-mode="first">
        <Rule>
            <Filter>[mapnik::geometry_type]=point</Filter>
            <MarkersSymbolizer
              file="pin-m.png"
              allow-overlap="true"
              ignore-placement="true"
            />
        </Rule>
    </Style>
    <Layer name="layer" srs="+init=epsg:4326">
        <StyleName>points</StyleName>
        <Datasource>
            <Parameter name="type">geojson</Parameter>
            <Parameter name="inline"><![CDATA[{"type":"FeatureCollection","features":[{"type":"Feature","geometry":{"type":"Point","coordinates":[-90,-8]},"properties":{}}]}]]></Parameter>
        </Datasource>
    </Layer>
</Map>

package.json

{
    "name": "gist-pointsymbolizer",
    "private": true,
    "dependencies": {
        "mapnik": "3.0.1",
        "sphericalmercator": "1.0.x"
    },
    "scripts": {
        "test": "node test.js"
    }
}

pin-m.png

point.png

point.xml

<Map srs="+init=epsg:3857" background-color="#ffffff">
    <Style name="points" filter-mode="first">
        <Rule>
            <Filter>[mapnik::geometry_type]=point</Filter>
            <PointSymbolizer
              file="pin-m.png"
              allow-overlap="true"
              ignore-placement="true"
            />
        </Rule>
    </Style>
    <Layer name="layer" srs="+init=epsg:4326">
        <StyleName>points</StyleName>
        <Datasource>
            <Parameter name="type">geojson</Parameter>
            <Parameter name="inline"><![CDATA[{"type":"FeatureCollection","features":[{"type":"Feature","geometry":{"type":"Point","coordinates":[-90,-8]},"properties":{}}]}]]></Parameter>
        </Datasource>
    </Layer>
</Map>

test.js

var fs = require('fs');
var mapnik = require('mapnik');
var sm = new (require('sphericalmercator'))();

mapnik.register_default_input_plugins();

function test(name) {
    var map = new mapnik.Map(256,256);
    map.fromStringSync(fs.readFileSync(__dirname + '/' + name + '.xml', 'utf8'));
    map.bufferSize = 64;

    map.extent = sm.bbox(0,0,1,false,'900913');
    var img1 = map.renderSync('png', new mapnik.Image(256,256));
    map.extent = sm.bbox(0,1,1,false,'900913');
    var img2 = map.renderSync('png', new mapnik.Image(256,256));

    mapnik.blend([
        { buffer: img1, x:0, y:0 },
        { buffer: img2, x:0, y:256 }
    ], function(err, joined) {
        if (err) throw err;
        fs.writeFileSync(__dirname + '/' + name + '.png', joined);
    });
}

test('marker');
test('point');