有个小程序项目,需要通过转盘的形式,进行数据录入,找了好久,终于找到。
看图
刻度盘进度盘.gif
刻度盘进度盘.gif

进度条刻度盘.gif
进度条刻度盘.gif

组件自定义属性

  /**
   * 组件的初始数据
  */
  properties: {
    startAngle:{
      type:Number,
      value: -Math.PI / 2, // 起始角度
    }, 
    lastAngle:{
      type: Number,
      value: -Math.PI / 2, // 终止角度
    }, 

    touchCircleR:{
      type: Number,
      value: 8, // 触摸圆的半径
    },

    touchCircleColor:{
      type: String,
      value: '#EFF2F5',// 触摸圆颜色
    }, 
    isCanTouch: {
      type: Boolean,
      value: false, // 是否相应触摸事件
    },
    touchCircleR: {
      type: Number,
      value: 8, // 触摸圆的半径
    },
    circleR: {
      type: Number,
      value: 70, // 指定轨道上出现触摸圆,
    },
    progressValue: {
      type: Number,
      value: 0, // 当前进度
    },
    circleCenterX: {
      type: Number,
      value: 150, // 大圆圆心坐标X轴
    },
    circleCenterY: {
      type: Number,
      value: 150, // 大圆圆心坐标Y轴
    },
    circleCenterR: {
      type: Number,
      value: 100, // 大圆圆心半径
    },
    circleCenterColor:{
      type:String,
      value: '#EDF0F3',// 大圆圆环颜色
    }, 
    circleCenterWidth:{
      type:Number,
      value: 4,// 大圆圆环宽度
    }, 
    progressCircleColor: {
      type:String,
      value: '#269073',// 进度圆环颜色
    },
    progressCircleWidth:{
      type:Number,
      value: 6,// 进度圆环宽度
    }, 
    gearWheelDefaultColor: {
      type: String,
      value: '#DCDFE0',// 齿轮默认颜色
    }, 
    gearWheelActiveColor: {
      type: String,
      value: 'rgba(38, 144, 115, 1)',// 齿轮激活颜色
    }, 
  },

绘制外圈

 // 绘制外圈
    whiteRedCircle: function (context) {
      context.save();
      context.beginPath();
      context.lineWidth = this.data.circleCenterWidth; //设置线宽
      context.strokeStyle = this.data.circleCenterColor;
      context.arc(this.data.circleCenterX, this.data.circleCenterY, this.data.circleCenterR, 0, Math.PI * 2, false);
      context.stroke();
      context.closePath();
      context.restore();
    },

绘制齿轮

 // 绘制齿轮
      drawGearWheel: function (context, rateNum){
        context.translate(this.data.circleCenterX, this.data.circleCenterY);
          context.save();
          let hasOver = parseInt(rateNum * 100);
          for (let i = 0; i < 100; i++) {
              context.beginPath();
              context.setLineWidth(1);
              if (i > hasOver) {
                context.setStrokeStyle(this.data.gearWheelDefaultColor);
                  context.moveTo(0, -110);
              } else if (i >= hasOver - 2 && i <= hasOver + 1) {
                context.setStrokeStyle(this.data.gearWheelActiveColor);
                  context.moveTo(0, -115);
              } else {
                  context.moveTo(0, -110);
                context.setStrokeStyle(this.data.gearWheelActiveColor);
              }

              context.lineTo(0, -95);
              context.stroke();
              context.rotate(3.6 * Math.PI / 180);
          }
      },

绘制触摸圆

drawTouchCirclr: function (context, rateNum) {
   context.save();
   context.beginPath();
   context.lineWidth = this.data.touchCircleR * 2; //设置线宽
   context.strokeStyle = this.data.touchCircleColor;
   context.arc(this.data.circleCenterX + this.data.circleR * Math.sin(rateNum * Math.PI * 2), this.data.circleCenterY - this.data.circleR * Math.cos(rateNum * Math.PI * 2), this.data.touchCircleR, 0, Math.PI * 2, false);
   context.stroke();
   context.closePath();
   context.restore();
 },

绘制进度外圈

drawWhiteCircle: function (context, n) {
  context.save();
  context.strokeStyle = this.data.progressCircleColor; //设置描边样式
  context.lineWidth = this.data.progressCircleWidth; //设置线宽
  context.beginPath(); //路径开始
  context.arc(this.data.circleCenterX, this.data.circleCenterY, this.data.circleCenterR, this.data.startAngle, this.data.startAngle + n * Math.PI * 2, false); //用于绘制圆弧           context.arc(x坐标,y坐标,半径,起始角度,终止角度,顺时针/逆时针)
  context.stroke(); //绘制
  context.closePath(); //路径结束
  context.restore();
},

写文字

drawText: function (ctx, str) {
  ctx.setFontSize(20);
  ctx.setTextAlign('center');
  let rel = parseInt((this.data.startAngle + str * Math.PI * 2 + Math.PI / 2) * 100 / (2 * Math.PI));
  let showText = rel + '%';
  ctx.fillText(showText, this.data.circleCenterX, 20);
},

重绘canvas

 drawInit(rateNum) {
   constctx = wx.createCanvasContext('credit-canvas',this);
   this.drawText(ctx, rateNum);
   // this.whiteRedCircle(ctx);
   // this.drawWhiteCircle(ctx, rateNum);
   this.drawTouchCirclr(ctx, rateNum);
   this.drawGearWheel(ctx,rateNum);
   ctx.draw();
   this.setData({
       progressValue: rateNum,
       lastAngle:360*rateNum
   });
 },

计算角度

canculateRate: function (newX, newY) {
   constMathX = Math.abs(newX - this.data.circleCenterX);
   const MathY = Math.abs(newY - this.data.circleCenterY);
   if (MathX == 0 || MathY == 0) {
     return;
   }
   // 计算移动终点相对圆心转过的角度
   let angle;
   if (newX > this.data.circleCenterX && newY < this.data.circleCenterY) {//第一象限
     angle = Math.atan(MathX / MathY) * 180 / Math.PI;
   } else if (newX >= this.data.circleCenterX && newY >= this.data.circleCenterY) {// 第二象限
     angle = 180 - Math.atan(MathX / MathY) * 180 / Math.PI;
   } else if (newX <= this.data.circleCenterX && newY >= this.data.circleCenterY) {//第三象限
     angle = 180 + Math.atan(MathX / MathY) * 180 / Math.PI;
   } else { // 第四象限
     angle = 360 - Math.atan(MathX / MathY) * 180 / Math.PI;
   }

   if (angle - this.data.lastAngle > 180) {// 当为零届点向左移动
     angle = 0;
   } else if (angle - this.data.lastAngle < -180) {// 当为临届点向右移动
     angle = 360;
   }
   // 转动的进度
   let rateNum = angle / 360;

   this.drawInit(rateNum);

   this.setData({
     progressValue: rateNum,
     lastAngle: angle
   });

 },

触摸移动方法

 // 触摸开始方法
    handleTouchStart: function (event) {
      let x = event.touches[0].x;
      let y = event.touches[0].y;

      let touchCircleX = 150 + this.data.circleR * Math.sin(this.data.progressValue * Math.PI * 2);
      let touchCircleY = 150 - this.data.circleR * Math.cos(this.data.progressValue * Math.PI * 2);

      if (touchCircleX + this.data.touchCircleR * 2 < x || x < touchCircleX - this.data.touchCircleR * 2 || touchCircleY + this.data.touchCircleR * 2 < y || y < touchCircleY - this.data.touchCircleR * 2) {
        this.setData({
          isCanTouch: false
        });
      } else {
        this.setData({
          isCanTouch: true,
        });
      }
    }

触摸开始方法

 // 触摸开始方法
    handleTouchStart: function (event) {
      let x = event.touches[0].x;
      let y = event.touches[0].y;

      let touchCircleX = 150 + this.data.circleR * Math.sin(this.data.progressValue * Math.PI * 2);
      let touchCircleY = 150 - this.data.circleR * Math.cos(this.data.progressValue * Math.PI * 2);

      if (touchCircleX + this.data.touchCircleR * 2 < x || x < touchCircleX - this.data.touchCircleR * 2 || touchCircleY + this.data.touchCircleR * 2 < y || y < touchCircleY - this.data.touchCircleR * 2) {
        this.setData({
          isCanTouch: false
        });
      } else {
        this.setData({
          isCanTouch: true,
        });
      }
    }

初始化canvas

    this.wxzxCirclePlate = this.selectComponent("#wxzxCirclePlate");
    this.wxzxCirclePlate.drawInit(0.99);

核心代码都在这里,如果有需要全部源代码的同学,云盘地址提取码:5t0c

如果有帮助,请点个赞,谢谢。

Q.E.D.