【MAPBOX基础功能】24、mapbox通过canvas方式绘制波纹点位

前言

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mapbox通过canvas方式绘制波纹点位
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效果

在这里插入图片描述

代码实现

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>24、通过canvas方式绘制波纹点位</title>
    <link
      href="https://api.mapbox.com/mapbox-gl-js/v2.7.0/mapbox-gl.css"
      rel="stylesheet"
    />
    <script src="https://api.mapbox.com/mapbox-gl-js/v2.7.0/mapbox-gl.js"></script>
    <style>
      * {
        padding: 0;
        margin: 0;
        list-style: none;
        text-decoration: none;
      }
      html,
      body {
        width: 100%;
        height: 100%;
      }
      #map {
        width: 100%;
        height: 100%;
      }
    </style>
  </head>
  <body>
    <div id="map"></div>
    <script>
      mapboxgl.accessToken =
        'pk.eyJ1Ijoid2FuZ3Rvbmd4dWUiLCJhIjoiY2pzY3E2M2k0MDk3NzN5dDA0Nmtia2h0cCJ9.oP9fEJxOgVzm0dWGvL6tGg'
      const map = new mapboxgl.Map({
        container: 'map', // 容器 id
        style: 'mapbox://styles/mapbox/streets-v11', // mapbox底图
        center: [108, 35], // 初始化中心点
        zoom: 2, // 初始化层级
      })
      map.on('load', () => {
        addCanvasRipple()
      })
      // 绘制marker类型的波纹点位
      function addCanvasRipple() {
        const pulsingDot = drawCanvas()
        map.addImage('pulsing-dot', pulsingDot, { pixelRatio: 2 })
        map.addLayer({
          id: 'points',
          type: 'symbol',
          source: {
            type: 'geojson',
            data: {
              type: 'FeatureCollection',
              features: [
                {
                  type: 'Feature',
                  geometry: {
                    type: 'Point',
                    coordinates: [108, 35],
                  },
                },
              ],
            },
          },
          layout: {
            'icon-image': 'pulsing-dot',
          },
        })
      }
      // 绘制canvas 图片
      function drawCanvas() {
        const size = 40
        return {
          width: size,
          height: size,
          data: new Uint8Array(size * size * 4),

          onAdd: function () {
            const canvas = document.createElement('canvas')
            canvas.width = this.width
            canvas.height = this.height
            this.context = canvas.getContext('2d')
          },

          render: function () {
            const duration = 1000
            const t = (performance.now() % duration) / duration

            const radius = (size / 2) * 0.3
            const outerRadius = (size / 2) * 0.7 * t + radius
            const context = this.context

            // draw outer circle
            context.clearRect(0, 0, this.width, this.height)
            context.beginPath()
            context.arc(
              this.width / 2,
              this.height / 2,
              outerRadius,
              0,
              Math.PI * 2
            )
            context.fillStyle = 'rgba(255, 0, 0, 0.5)'
            context.fill()

            this.data = context.getImageData(0, 0, this.width, this.height).data
            map.triggerRepaint()
            return true
          },
        }
      }
    </script>
  </body>
</html>

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原文地址：https://blog.csdn.net/weixin_44402694/article/details/125421497