iD/js/id/svg/points.js

iD.svg.Points = function(projection, context) {
    function markerPath(selection, klass) {
        selection
            .attr('class', klass)
            .attr('transform', 'translate(-8, -23)')
            .attr('d', 'M 17,8 C 17,13 11,21 8.5,23.5 C 6,21 0,13 0,8 C 0,4 4,-0.5 8.5,-0.5 C 13,-0.5 17,4 17,8 z');
    }

    function sortY(a, b) {
        return b.loc[1] - a.loc[1];
    }

    return function drawPoints(surface, graph, entities, filter) {
        var points = [];

        for (var i = 0; i < entities.length; i++) {
            var entity = entities[i];
            if (entity.geometry(graph) === 'point') {
                points.push(entity);
            }
        }

        if (points.length > 100) {
            return surface.select('.layer-hit').selectAll('g.point').remove();
        }

        points.sort(sortY);

        var groups = surface.select('.layer-hit').selectAll('g.point')
            .filter(filter)
            .data(points, iD.Entity.key);

        var group = groups.enter()
            .append('g')
            .attr('class', 'node point')
            .order();

        group.append('path')
            .call(markerPath, 'shadow');

        group.append('path')
            .call(markerPath, 'stroke');

        group.append('use')
            .attr('class', 'icon')
            .attr('transform', 'translate(-6, -20)')
            .attr('clip-path', 'url(#clip-square-12)');

        groups.attr('transform', iD.svg.PointTransform(projection))
            .call(iD.svg.TagClasses())
            .call(iD.svg.MemberClasses(graph));

        // Selecting the following implicitly
        // sets the data (point entity) on the element
        groups.select('.shadow');
        groups.select('.stroke');
        groups.select('.icon')
            .attr('xlink:href', function(entity) {
                var preset = context.presets().match(entity, graph);
                return preset.icon ? '#maki-' + preset.icon + '-12' : '';
            });

        groups.exit()
            .remove();
    };
};