Vue 用 Canvas 生成随机大小 不重叠圆

canvas 相关文档

• Canvas Api
• CANVAS速查简表

效果图展示

• 第一张是 随机颜色随机大小聚合 在一起效果
  随机颜色

• 第二张是 随机背景图片随机大小分散 效果（这里我使用的图片都一样所以没展现出不同图片）

案例完整代码

• 本实例是用 vue 来实现的，其他方法和 vue 类似，改为对应的语法即可实现效果。
• 案例用到了 vue 父子组件传值

父组件代码

<template>
  <div id="home">
      <div class="tags" ref="tags">
        <circle-box :parentClientWidth="parentClientWidth" :parentClientHeight="parentClientHeight" :dataList="dataList"></circle-box>
      </div>
  </div>
</template>

<script>
import CircleBox from '@/components/content/circle/Circle.vue'
export default {
  components: { CircleBox },
  data() {
    return {
      parentClientWidth: 0,
      parentClientHeight: 0,
      // canvas 模拟数据
      dataList: [
       {
          follow: 1,
          image: 'http://39.99.139.115/demo/RB5.png'
        },
        {
          follow: 2,
          image: 'http://39.99.139.115/demo/RB5.png'
        },
        {
          follow: 3,
          image: 'http://39.99.139.115/demo/RB5.png'
        },
        {
          follow: 4,
          image: 'http://39.99.139.115/demo/RB5.png'
        },
        {
          follow: 5,
          image: 'http://39.99.139.115/demo/RB5.png'
        },
        {
          follow: 6,
          image: 'http://39.99.139.115/demo/RB5.png'
        },
        {
          follow: 7,
          image: 'http://39.99.139.115/demo/RB5.png'
        },
        {
          follow: 8,
          image: 'http://39.99.139.115/demo/RB5.png'
        },
        {
          follow: 9,
          image: 'http://39.99.139.115/demo/RB5.png'
        },
        {
          follow: 10,
          image: 'http://39.99.139.115/demo/RB5.png'
        }
      ],
    };
  },
  
  created() {},
  
  mounted() {
    this.getWidth();
  },
  
  methods: {
    // 获取父盒子的宽度和高度
    getWidth() {
      this.parentClientWidth = this.$refs.tags.clientWidth;
      this.parentClientHeight = this.$refs.tags.clientHeight;
      console.log(this.$refs.tags.clientWidth);
    }
  },
};
</script>

子组件代码

<template>
  <div>
    <canvas id="myCanvas" :width="parentClientWidth + 'px'" :height="parentClientHeight + 'px'"></canvas>
  </div>
</template>

<script>
export default {
  // 接收数据
  props: ['parentClientWidth', 'parentClientHeight', 'dataList'],

  data() {
    return {
      dataListCopy: this.dataList
    }
  },
  
  created() {
    this.$nextTick(() => {
      // 初始化
      this.circleInfo()
    })
  },
  
  mounted() {},
  
  methods: {
    circleInfo() {
      let that = this
      class Circle {
        constructor(x, y, r, color) {
          this.x = x
          this.y = y
          this.r = r
          this.c = color ? color : this.getRandomColor()
        }

        // 随机颜色
        getRandomColor() {
          let r = Math.floor(Math.random() * 100) + 155
          let g = Math.floor(Math.random() * 100) + 155
          let b = Math.floor(Math.random() * 100) + 155
          return `rgb(${r},${g},${b})`
        }
      }

      class RandomCircle {
        constructor(obj) {
          this.c = document.getElementById(obj.id)
          console.log(this.c)

          this.ctx = this.c.getContext('2d')
          this.dWidth = this.c.width
          this.dHeight = this.c.height
          this.fix = obj.fix || true

          this.minMargin = obj.minMargin || 20
          this.minRadius = obj.minRadius || 30
          this.radiuArr = obj.radiuArr || [30, 30, 30, 30, 30, 30, 30, 30, 30, 30]

          this.total = obj.total || 10

          this.circleArray = []
          this.circleNumber = 1
        }

        drawOneCircle(c, index) {
          // console.log(c, index)
          let ctx = this.ctx

          ctx.beginPath()

          ctx.strokeStyle = c.c
          ctx.fillStyle = c.c
          // 画圆
          ctx.arc(c.x, c.y, c.r, 0, 2 * Math.PI)

          ctx.stroke()
          ctx.fill()

          // ctx.textAlign = 'center'
          // ctx.textBaseline = 'middle'

          // ctx.fillStyle = 'black'
          // ctx.font = '1rem 微软雅黑'
          // ctx.fillText(that.dataListCopy[index].follow, c.x, c.y - 10) //圆内文字

          let img = new Image()
          img.src = that.dataListCopy[index].image
          ctx.drawImage(img, c.x - c.r, c.y - c.r, c.r * 2, c.r * 2)

          this.circleNumber++
        }

        check(x, y, r) {
          return !(x + r > this.dWidth || x - r < 0 || y + r > this.dHeight || y - r < 0)
        }

        // 获取一个新圆的半径，主要判断半径与最近的一个圆的距离
        getR(x, y) {
          if (this.circleArray.length === 0) return Math.floor(Math.random() * 20 + 20)

          let lenArr = this.circleArray.map((c) => {
            let xSpan = c.x - x
            let ySpan = c.y - y

            return Math.floor(Math.sqrt(Math.pow(xSpan, 2) + Math.pow(ySpan, 2))) - c.r
          })

          let minCircleLen = Math.min(...lenArr)
          let minC = this.circleArray[lenArr.indexOf(minCircleLen)]
          let tempR = this.fix ? this.radiuArr[this.circleArray.length] : minCircleLen - this.minMargin
          let bool = this.fix ? tempR <= minCircleLen - minC.r : tempR >= this.minRadius

          return bool ? tempR : false
        }

        // 生成一个圆，随机生成圆心。
        // 如果连续生成200次半径都没有合适的话，终止进程
        createOneCircle() {
          let x, y, r
          let createCircleTimes = 0

          while (true) {
            createCircleTimes++
            x = Math.floor(Math.random() * this.dWidth)
            y = Math.floor(Math.random() * this.dHeight)

            let TR = this.getR(x, y)
            if (!TR) {
              continue
            } else {
              r = TR
            }
            if (this.check(x, y, r) || createCircleTimes > 200) {
              break
            }
          }

          this.check(x, y, r) && this.circleArray.push(new Circle(x, y, r))
        }

        // 如果生成100次新圆都失败的话，终止方案。
        // 如果生成100种方案都没有合适可用的话，终止进程。
        init() {
          let n = 0

          while (this.circleArray.length < this.total) {
            this.circleArray = []

            let i = 0
            while (this.circleArray.length < this.total) {
              this.createOneCircle()
              i++
              if (i >= 100) {
                break
              }
            }

            n++

            if (n > 100) {
              break
            }
          }

          // 根据半径从大到小画圆。
          this.circleArray
            .sort((a, b) => b.r - a.r)
            .forEach((c, index) => {
              this.drawOneCircle(c, index)
            })
        }
      }
      // console.log(this.circle);

      const p = new RandomCircle({
        id: 'myCanvas',
        total: that.dataListCopy.length // 配置数量
      })

      p.init()
      console.log(p)
      console.log(p.circleArray)
    }
  }
}
</script>