maptalks 开发GIS地图（27）maptalks.three.20

1. 自定义圆圈，从效果上来看，并没有太惊艳，普通的canvas应用，不过圆圈的颜色是渐变色，

这个还是头一次看到实际的应用，平时不太敢想这么去做。

2. 渐变色是使用 canvas 制作的。使用了 ctx.createLinearGradient。

        function getMaterial(fontSize, text, fillColor) {
            var SIZE = 256;
            var canvas = document.createElement('canvas');
            canvas.width = canvas.height = SIZE;
            var ctx = canvas.getContext('2d');
            var gradient = ctx.createLinearGradient(0, 0, SIZE, 0);
            // gradient.addColorStop("0", "#ffffff");
            gradient.addColorStop("0.0", "#1a9bfc");
            gradient.addColorStop("1.0", "#7049f0");
            // gradient.addColorStop("0.66", "white");
            // gradient.addColorStop("1.0", "red");

            ctx.strokeStyle = gradient;
            ctx.lineWidth = 40;
            ctx.arc(SIZE / 2, SIZE / 2, SIZE / 2, 0, Math.PI * 2);
            ctx.stroke();
            ctx.fillStyle = fillColor;
            ctx.font = `${fontSize}px Aria`;
            ctx.textAlign = 'center';
            ctx.textBaseline = 'middle';
            ctx.fillText(text, SIZE / 2, SIZE / 2);
            ctx.rect(0, 0, SIZE, SIZE);
            var texture = new THREE.Texture(canvas);
            texture.needsUpdate = true; //使用贴图时进行更新

            var material = new THREE.MeshPhongMaterial({
                map: texture,
                // side: THREE.DoubleSide,
                transparent: true
            });
            return material;
        }

3. 添加圆圈

function addCircles() {
            var lnglats = [
                [13.429362937522342, 52.518205849377495]
                , [13.41688993786238, 52.52216099633924]
                , [13.417991247928398, 52.53296954185342]
                , [13.438154245439819, 52.533321196953096]
                , [13.450418871799684, 52.52653968753597]
                , [13.390340036780685, 52.51953598324846]
                , [13.399921081391199, 52.50920191922407]
                , [13.366122901455583, 52.50949703597493]
                , [13.365784792637783, 52.51964629275582]
                , [13.371429857108524, 52.528732386936014]
                , [13.383686384074508, 52.53781463596616]
                , [13.40395563186371, 52.540223413847315]
                , [13.361485408920998, 52.53916869831616]
                , [13.35373758485457, 52.52883597474849]
                , [13.355233792792774, 52.519259850666316]
                , [13.369548077301943, 52.506940362998336]
                , [13.338732610093984, 52.50860998116909]
                , [13.341879792058194, 52.52318729489704]
                , [13.348448231846305, 52.537668773653735]
            ];
            var text = Math.round(Math.random() * 10000);
            var material = getMaterial(70, text, '#fff');
            circles = lnglats.map(function (lnglat) {
                var circle = new Circle(lnglat, {
                    radius: 200
                }, material, threeLayer);

                //tooltip test
                circle.setToolTip('id:' + circle.getId(), {
                    showTimeout: 0,
                    eventsPropagation: true,
                    dx: 10
                });


                //infowindow test
                circle.setInfoWindow({
                    content: 'id:' + circle.getId(),
                    title: 'message',
                    animationDuration: 0,
                    autoOpenOn: false
                });


                //event test
                ['click', 'mousemove', 'mouseout', 'mouseover', 'mousedown', 'mouseup', 'dblclick', 'contextmenu'].forEach(function (eventType) {
                    circle.on(eventType, function (e) {
                        console.log(e.type, e);
                    });
                });
                return circle;
            });
            threeLayer.addMesh(circles);

            initGui();
        }

4. 页面显示

5. 源码地址

https://github.com/WhatGIS/maptalkMap/tree/main/threelayer/demo