<template>
  <canvas :canvas-id="'progress'+id" :style="{width: sizeNum + 'px', height: sizeNum + 'px'}"></canvas>
  <slot></slot>
</template>

<script>
export default {
  props: {
    id:{
      type: String,
    },
    progressColor: { //进度颜色
      type: String,
      default: '#409EFF'
    },
    bgColor: {   //轨道颜色
      type: String,
      default: '#F9FAFB'
    },
    size: {   //整体大小
      type: Number,
      default: 100
    },
    strokeWidth: { //轨道宽度
      type: Number,
      default: 20
    },
    percent: {  //进度百分比
      type: Number,
      default: 0
    }
  },
  data(){
    return{
      sizeNum:this.size,  //最终的整体尺寸
      strokeWidthNum:this.strokeWidth,  //最终的轨道宽度数值
    }
  },
  mounted() {
    this.drawProgress()
  },
  methods: {
    drawProgress() {

      //尺寸与轨道宽度自适应处理
      const screenWidth = uni.getSystemInfoSync().screenWidth;
      this.sizeNum=(this.size/750)*screenWidth
      this.strokeWidthNum=(this.strokeWidth/750)*screenWidth


      const ctx = uni.createCanvasContext(`progress${this.id}`, this)
      const centerX = this.sizeNum / 2
      const centerY = this.sizeNum / 2
      const radius = (this.sizeNum - this.strokeWidthNum) / 2
      const startAngle = -Math.PI / 2
      const endAngle = startAngle + (this.percent / 100) * 2 * Math.PI
      // 绘制背景圆
      ctx.beginPath()
      ctx.arc(centerX, centerY, radius, 0, 2 * Math.PI)
      ctx.setFillStyle('#FFFFFF')
      ctx.fill()
      // 绘制轨道圆环
      ctx.beginPath()
      ctx.arc(centerX, centerY, radius, 0, 2 * Math.PI)
      ctx.setLineWidth(this.strokeWidthNum)
      ctx.setStrokeStyle(this.bgColor)
      ctx.setLineCap('round')
      ctx.stroke()
      // 绘制进度圆环
      ctx.beginPath()
      ctx.arc(centerX, centerY, radius, startAngle, endAngle)
      ctx.setLineWidth(this.strokeWidthNum)
      ctx.setStrokeStyle(this.progressColor)
      ctx.setLineCap('round')
      ctx.stroke()
      ctx.draw(true)
    }
  },
  watch: {
    percent() {
      this.drawProgress()
    }
  }
}
</script>

