Method constructor

src/openlayers/overlay/HeatMap.js:42–103

(name, opt_options)

export class HeatMap extends ImageCanvasSource {

    constructor(name, opt_options) {
        var options = opt_options ? opt_options : {};
        super({
            attributions: options.attributions || "Map Data <span>© SuperMap iServer</span> with <span>© SuperMap iClient</span>",
            canvasFunction: canvasFunctionInternal_,
            logo: Util.getOlVersion() === '4' ? options.logo : null,
            projection: options.projection,
            ratio: options.ratio,
            resolutions: options.resolutions,
            state: options.state
        });

        function canvasFunctionInternal_(extent, resolution, pixelRatio, size, projection) { // eslint-disable-line no-unused-vars
            var mapWidth = size[0] * pixelRatio;
            var mapHeight = size[1] * pixelRatio;

            this.rootCanvas.width = this.maxWidth = mapWidth;
            this.rootCanvas.height = this.maxHeight = mapHeight;
            if (!this.features) {
                return this.rootCanvas;
            }
            this.pixelRatio = pixelRatio;

            //记录偏移量
            var width = this.map.getSize()[0] * pixelRatio;
            var height = this.map.getSize()[1] * pixelRatio;
            this.offset = [(mapWidth - width) / 2 / pixelRatio, (mapHeight - height) / 2 / pixelRatio];

            this.updateHeatPoints(resolution);

            return this.rootCanvas;
        }

        //初始化成员变量
        this.canvasFunctionInternal_ = canvasFunctionInternal_;
        this.features = [];
        this.name = name;
        if (!options.map) {
            throw new Error('options.map is not found.');
        }
        this.map = options.map;
        // this.TFEvents = options.TFEvents || [];
        this.id = options.id ? options.id : CommonUtil.createUniqueID("HeatMapSource_");
        this.opacity = options.opacity ? options.opacity : 1;
        this.colors = options.colors ? options.colors : ['blue', 'cyan', 'lime', 'yellow', 'red'];
        this.useGeoUnit = options.useGeoUnit ? options.useGeoUnit : false;
        this.radius = options.radius ? options.radius : 50;
        this.featureWeight = options.featureWeight ? options.featureWeight : null;
        this.maxWeight = null;
        this.minWeight = null;
        this.maxWidth = null;
        this.maxHeight = null;

        //创建热力图绘制面板
        this.rootCanvas = document.createElement("canvas");
        var mapSize = this.map.getSize();
        this.rootCanvas.width = this.maxWidth = parseInt(mapSize[0]);
        this.rootCanvas.height = this.maxHeight = parseInt(mapSize[1]);