Vue有趣的可旋转转盘组件

使用 vue 编写的一个可旋转组件，如图

• 布局

  • 用卡片数量均分 360 度圆，使用绝对定位分布在外部容器上，自身通过 rotate 旋转

     
         computedCardPosStyle(index){
         let deg = index * this.unitCardDeg;
         let absDeg = Math.abs((deg + this.turnRotate) % 360);
         let z_index = absDeg > 180 ? Math.ceil(absDeg-180): Math.ceil(180-absDeg);
     
         return {
             width: this.cardWidth + "px",
             height: this.cardHeight + "px",
             top: -Math.cos(deg*Math.PI/180)*this.turntableR + "px",
             left: Math.sin(deg*Math.PI/180)*this.turntableR + "px",
             transform: `translate(-50%, -50%) rotate(${deg}deg)`,
             zIndex: z_index
         }
     },

  • 外部容器定位于浏览器窗口之下，露出正上方部分出来

     <div 
         class="container"
         :style="{width: `${turntableR*2 + cardWidth}px`,
             height: `${turntableR*2 + cardHeight}px`,
             left: `${screenWidth/2 - turntableR-cardWidth/2}px`,
             top: `${outerWrap? -(1-wrapScale)*(turntableR+cardHeight/2) + screenHeight - wrapScale*(cardHeight + bottomPos + cardHeight*reletiveTop): 
                 -(1-wrapScale)*(turntableR+cardHeight/2)
             }px`,
             transform: `scale(${wrapScale})`,
         }"ref="container"
     >
      ...
    </div>

• 圆盘的转动

  • onmousedown、onmouseup 用来判断鼠标是否处于按下状态，并且清空上一次拖动的数据
  • 圆盘的转动以横向滑动的总距离更新角度

  • 针对圆盘如何转动，设计按每一个小的间隔时间（如 20ms），叠加一次总体滑动的距离

    handleMouseDown(e){e.preventDefault();
        clearInterval(this.UDLMactionTimer);
        this.mouseIsDown = true;
        this.startX = e.clientX || e.touches[0].clientX;
        this.endX = e.clientX || e.touches[0].clientX;
    },
    handleMouseUp(e){e.preventDefault();
        this.mouseIsDown = false;
        clearInterval(this.timer);
        clearInterval(this.UDLMactionTimer);
        this.timer = null;
        this.startX = 0;
        this.endX = 0;
        if(this.lastSpeed) this.UDLMaction();},
    handleMouseMove(e){e.preventDefault();
        this.endX = e.clientX || e.touches[0].clientX;
        if(!this.mouseIsDown) return;
        if(!this.timer){this.timer = setInterval(() => {
                let moveGap = this.endX - this.startX;
     
                this.lastSpeed = moveGap/this.timeGap;
                this.xGap += moveGap;
                this.direction = moveGap > 0 ? 1 : -1;
                this.startX = this.endX;
            }, this.timeGap);
        }
    },
     
    mounted(){
    let container_dom = this.outerWrap ? this.$refs.outerWrap : this.$refs.container;
     
    container_dom.addEventListener('mousedown', this.handleMouseDown.bind(this));
    container_dom.addEventListener('mouseup', this.handleMouseUp.bind(this));
    container_dom.addEventListener('mouseleave', this.handleMouseUp.bind(this));
    container_dom.addEventListener('mousemove', this.handleMouseMove.bind(this));
    container_dom.addEventListener('touchstart', this.handleMouseDown.bind(this));
    container_dom.addEventListener('touchend', this.handleMouseUp.bind(this));
    container_dom.addEventListener('touchcancel', this.handleMouseUp.bind(this));
    container_dom.addEventListener('touchmove', this.handleMouseMove.bind(this));
     
    window.addEventListener('resize', this.responseContainerScale.bind(this));
    window.addEventListener('load', this.responseContainerScale.bind(this));
    },
    beforeDestroy(){
        let container_dom = this.outerWrap ? this.$refs.outerWrap : this.$refs.container;
     
        container_dom.removeEventListener('mousedown', this.handleMouseDown.bind(this));
        container_dom.removeEventListener('mouseup', this.handleMouseUp.bind(this));
        container_dom.removeEventListener('mouseleave', this.handleMouseUp.bind(this));
        container_dom.removeEventListener('mousemove', this.handleMouseMove.bind(this));
        container_dom.removeEventListener('touchstart', this.handleMouseDown.bind(this));
        container_dom.removeEventListener('touchend', this.handleMouseUp.bind(this));
        container_dom.removeEventListener('touchcancel', this.handleMouseUp.bind(this));
        container_dom.removeEventListener('touchmove', this.handleMouseMove.bind(this));
     
        window.removeEventListener('resize', this.responseContainerScale.bind(this));
    }

• 旋转效果平滑

   如果没有滑动惯性，当滑动完之后，无论滑动的时候速度如何的快，在松开鼠标后转盘立刻停下，使得效果非常生硬。所以在滑动完成之后，利用最后时刻的滑动速度，让转盘做匀减速运动直至速度为 0，并且在速度为 0 时，在设计缓慢细小的匀速滑动，最后呈现出来的效果就比较平滑了。UDLMaction(){
         let a = -this.reduceSpeed*this.direction;
         this.UDLMactionTimer = setInterval(() => {this.lastSpeed = (this.lastSpeed + a)*this.direction >= 0? this.lastSpeed + a: 0;
             this.xGap += (this.lastSpeed) * this.timeGap;
             if(!this.lastSpeed){this.moreDynamic();
                 return clearInterval(this.UDLMactionTimer);
             }
         }, this.timeGap);
     },
     moreDynamic(){
         let time = 10;
         let timer = setInterval(() => {
             this.xGap += this.direction*3;
             if(--time <= 0) clearInterval(timer);
         }, 20)
     },
     

• demo 地址：https://github.com/tanf1995/m…

• 请教

  本来设想的是通过 prop 来传递卡片的内部结构和数组数据，例如传递一个渲染函数，通过 react 可以轻松的实现, 但是 vue 这招行不通。请问如何能够做到这点呢？react 伪代码如下

     <Component
         renderItem={item => <Child propName={item.props} data={item.data} />}
     >
     </Component>