Method constructor

src/openlayers/overlay/theme/Theme.js:42–131

(name, opt_options)

export class Theme 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 Theme.prototype.on
        * @description 添加专题要素事件监听。支持的事件包括: click、mousedown、mousemove、mouseout、mouseover、mouseup。
        * @param {string} event - 事件名称。
        * @param {RequestCallback} callback - 事件回调函数。
        */
        this.on = this.onInternal;
        this.id = options.id ? options.id : CommonUtil.createUniqueID("themeLayer_");

        function canvasFunctionInternal_(extent, resolution, pixelRatio, size, projection) { // eslint-disable-line no-unused-vars
            var mapWidth = size[0] * pixelRatio;
            var mapHeight = size[1] * pixelRatio;
            if (!this.context) {
                this.context = Util.createCanvasContext2D(mapWidth, mapHeight);
            }
            if (!this.features) {
                return this.context.canvas;
            }
            this.pixelRatio = pixelRatio;

            var width = this.map.getSize()[0] * pixelRatio;
            var height = this.map.getSize()[1] * pixelRatio;
            this.offset = [(mapWidth - width) / 2 / pixelRatio, (mapHeight - height) / 2 / pixelRatio];
            if (!this.notFirst) {
                this.redrawThematicFeatures(extent);
                this.notFirst = true;
            }
            this.div.id = this.id;
            this.div.className = "themeLayer";
            this.div.style.width = mapWidth + "px";
            this.div.style.height = mapHeight + "px";
            this.map.getViewport().appendChild(this.div);
            this.renderer.resize();
            this.map.getViewport().removeChild(this.div);
            this.themeCanvas = this.renderer.painter.root.getElementsByTagName('canvas')[0];
            this.themeCanvas.width = mapWidth;
            this.themeCanvas.height = mapHeight;
            this.themeCanvas.style.width = mapWidth + "px";
            this.themeCanvas.style.height = mapHeight + "px";
            this.themeCanvas.getContext('2d').clearRect(0, 0, mapWidth, mapHeight);

            var highLightContext = this.renderer.painter._layers.hover.ctx;
            var highlightCanvas = highLightContext.canvas;
            var copyHighLightContext = Util.createCanvasContext2D(mapWidth, mapHeight);
            copyHighLightContext.drawImage(highlightCanvas, 0, 0, highlightCanvas.width, highlightCanvas.height, 0, 0, mapWidth, mapHeight);

            this.redrawThematicFeatures(extent);