JavaScript实现固定区域内不重叠随机圆生成算法

代码实现与配置

// 参数
let obj = {
  id: string, // canvas 的id
  fix：boolean, // 是否固定半径，默认为false
  minMargin： Number, // 两个圆的最短距离，默认为10
  minRadius: Number, 最小的圆半径，默认为30
  radiuArr: Array, 圆的半径的数组，当fix为true时该值必须填
  total: Number ，圆的个数，默认为10
} 

<!DOCTYPE html>
<html>
<body>

<canvas id="myCanvas" width="500" height="500" style="border:1px solid #d3d3d3;">
Your browser does not support the HTML5 canvas tag.
</canvas>

<script>
class Circle {
  constructor(x, y, r, color){
    this.x = x
    this.y = y
    this.r = r,
    this.c = color ? color : this.getRandomColor()
  }
  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);
    this.ctx     = this.c.getContext("2d");
    this.dWidth   = this.c.width;
    this.dHeight   = this.c.height

    this.fix     = obj.fix || false;
    this.minMargin  = obj.minMargin || 10 
    this.minRadius  = obj.minRadius || 30
    this.radiuArr  = obj.radiuArr || [80,70,60,50,45,40,40,35,35,30]
    this.total = obj.total || 10
    this.circleArray = []
    this.circleNumber = 1
  }


  drawOneCircle(c) {
    let ctx = this.ctx;
    ctx.beginPath();
    ctx.strokeStyle = c.c;
    ctx.fillStyle=c.c;
    ctx.arc(c.x, c.y, c.r, 0, 2*Math.PI);
    ctx.stroke();
    ctx.fill();

    ctx.fillStyle='black';
    ctx.fillText('No:'+this.circleNumber, c.x-10, c.y-5);
    ctx.fillText('R:'+c.r, c.x-10, c.y+5);
    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 + 80)
    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 => {
      this.drawOneCircle(c)
    })
  }
}


let p = new RandomCircle({id: 'myCanvas', total: 20})
p.init()

console.log(p.circleArray)

</script> 
</body>
</html>