iD/modules/ui/core/lasso.js

import { Toggle } from './toggle';

export function Lasso(context) {
    var group, polygon;

    lasso.coordinates = [];

    function lasso(selection) {

        context.container().classed('lasso', true);

        group = selection.append('g')
            .attr('class', 'lasso hide');

        polygon = group.append('path')
            .attr('class', 'lasso-path');

        group.call(Toggle(true));

    }

    function draw() {
        if (polygon) {
            polygon.data([lasso.coordinates])
                .attr('d', function(d) { return 'M' + d.join(' L') + ' Z'; });
        }
    }

    lasso.extent = function () {
        return lasso.coordinates.reduce(function(extent, point) {
            return extent.extend(iD.geo.Extent(point));
        }, iD.geo.Extent());
    };

    lasso.p = function(_) {
        if (!arguments.length) return lasso;
        lasso.coordinates.push(_);
        draw();
        return lasso;
    };

    lasso.close = function() {
        if (group) {
            group.call(Toggle(false, function() {
                d3.select(this).remove();
            }));
        }
        context.container().classed('lasso', false);
    };

    return lasso;
}