自定义绘制引擎

通过修改PointSimplifier.renderNormalPoints方法重新定制绘制引擎。

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          <!-- 重点：MyCanvasRender， renderConstructor -->
<!doctype html>
<html lang="zh-CN">

<head>
    <!-- 原始地址：//webapi.amap.com/ui/1.1/ui/misc/PointSimplifier/examples/custom-render.html -->
    <base href="//webapi.amap.com/ui/1.1/ui/misc/PointSimplifier/examples/" />
    <meta charset="utf-8">
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no, width=device-width">
    <title>自定义绘制引擎</title>
    <style>
    html,
    body,
    #container {
        width: 100%;
        height: 100%;
        margin: 0px;
    }
    
    #loadingTip {
        position: absolute;
        z-index: 9999;
        top: 0;
        right: 0;
        padding: 3px 10px;
        background: red;
        color: #fff;
        font-size: 13px;
    }
    </style>
</head>

<body>
    <div id="container"></div>
    <script type="text/javascript" src='//webapi.amap.com/maps?v=2.0&key=您申请的key值'></script>
    <!-- UI组件库 1.0 -->
    <script src="//webapi.amap.com/ui/1.1/main.js?v=1.1.1"></script>
    <script type="text/javascript">
    //创建地图
    var map = new AMap.Map('container', {
        zoom: 4
    });

    AMapUI.load(['ui/misc/PointSimplifier', 'lib/utils', 'lib/$'], function(PointSimplifier, utils, $) {

        if (!PointSimplifier.supportCanvas) {
            alert('当前环境不支持 Canvas！');
            return;
        }

        /**
         * 自定义的分组绘制引擎，仅作示例,功能类似于 PointSimplifier.Render.Canvas.GroupStyleRender
         * @param {PointSimplifier} pointSimplifierIns 关联的PointSimplifier实例
         * @param {Object} opts   配置
         */
        function MyCanvasRender(pointSimplifierIns, opts) {
            //直接调用父类的构造函数
            MyCanvasRender.__super__.constructor.apply(this, arguments);
        }

        //继承自默认的Canvas引擎（http://webapi.amap.com/ui/1.0/ui/misc/PointSimplifier/render/canvas.js）
        utils.inherit(MyCanvasRender, PointSimplifier.Render.Canvas);

        utils.extend(MyCanvasRender.prototype, {
            /**
             * 重新实现点的绘制方法
             * @param  {number} zoom       当前的地图级别
             * @param  {Array} activePoints 可以正常绘制的点
             * @param  {Array} shadowPoints 空间被占用的点
             */
            renderNormalPoints: function(zoom, activePoints, shadowPoints) {
                //先按默认逻辑处理shadowPoints
                MyCanvasRender.__super__.renderNormalPoints.call(this, zoom, null, shadowPoints);

                var pointStyle = this.getOption('pointStyle'),
                    getPointsGroupKey = this.getOption('getPointsGroupKey'),
                    pointStyleGroup = this.getOption('pointStyleGroup'),
                    pointSimplifierIns = this.getPointSimplifierInstance(),
                    groups = {};

                //按key分组
                for (var i = 0, len = activePoints.length; i < len; i++) {

                    var point = activePoints[i],
                        dataIndex = point.idx,
                        dataItem = pointSimplifierIns.getDataItemByIndex(dataIndex);

                    var key = getPointsGroupKey.call(this, dataItem, dataIndex);

                    if (!groups[key]) {
                        groups[key] = [];
                    }

                    groups[key].push(activePoints[i]);
                }

                //分组绘制
                for (var k in groups) {

                    //继承pointStyle中的默认属性
                    var styleOptions = utils.extend({}, pointStyle, pointStyleGroup[k]);

                    //调用父类的绘制函数
                    this.drawPointsWithStyleOptions(groups[k], styleOptions);
                }
            }
        });


        var pointSimplifierIns = new PointSimplifier({

            zIndex: 300,
            map: map,
            getPosition: function(item) {

                if (!item) {
                    return null;
                }

                var parts = item.split(',');

                return [parseFloat(parts[0]), parseFloat(parts[1])];
            },
            getHoverTitle: function(dataItem, idx) {
                return '序号: ' + idx;
            },
            //赋值为 MyCanvasRender
            renderConstructor: MyCanvasRender,
            renderOptions: {
                getPointsGroupKey: function(dataItem, dataIndex) {
                    //这里直接按索引取余，仅作示意
                    return 'g' + dataIndex % 5;
                },
                //分组配置
                pointStyleGroup: {
                    'g0': {
                        fillStyle: '#3366cc'
                    },
                    'g1': {
                        fillStyle: '#dc3912'
                    },
                    'g2': {
                        fillStyle: '#ff9900'
                    },
                    'g3': {
                        fillStyle: '#109618'
                    },
                    'g4': {
                        fillStyle: '#990099'
                    }
                }
            }
        });

        $('<div id="loadingTip">加载数据，请稍候...</div>').appendTo(document.body);
        $.get('http://a.amap.com/amap-ui/static/data/10w.txt', function(csv) {

            var data = csv.split('\n');

            pointSimplifierIns.setData(data);

            $('#loadingTip').remove();
        });
    });
    </script>
</body>

</html>
        
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