画像のシームレスなスクロールを実現する js

class Roll { constructor(opts) { this.elem = opts.elem; // 图片包含滚动长度的元素的 this.elemBox = opts.elemBox; //图片展示区域元素，为了获取展示区域的高度 this.direction = opts.direction; this.time = opts.time; this.init(); this.roll = this.roll.bind(this) this.startRoll = this.startRoll.bind(this) this.stopRoll = this.stopRoll.bind(this) } init(){ this.elemHeight = this.elem.offsetHeight; this.elemHtml = this.elem.innerHTML; this.elem.innerHTML = this.elem.innerHTML + this.elemHtml+ this.elemHtml; this.speed; // 如果向上滚或者向左滚动每次减1，向下滚或者向右滚动每次加1 if(this.direction === 'top' || this.direction === 'left'){ this.speed = -1; }else{ this.speed = 1; } } roll(){ switch (this.direction) { case "top": // 如果滚动的盒子的top值超出元素的高度，则置为0 if(Math.abs(this.elemBox.offsetTop) >= this.elemHeight){ this.elemBox.style.top = 0; }else{ this.elemBox.style.top = this.elemBox.offsetTop + this.speed + 'px'; } break; case "bottom": // 如果滚动的盒子的bottom值超出元素的高度，则置为0 if(Math.abs(this.elemBox.offsetBottom) >= this.elemHeight){ this.elemBox.style.bottom = 0; }else{ this.elemBox.style.bottom = this.elemBox.offsetBottom + this.speed + 'px'; } break; case "left": // 如果滚动的盒子的left超出元素的高度，则置为0 if(Math.abs(this.elemBox.offsetLeft) >= this.elemHeight){ this.elemBox.style.left = 0; }else{ this.elemBox.style.left = this.elemBox.offsetLeft + this.speed + 'px'; } break; case "right": // 如果滚动的盒子的right超出元素的高度，则置为0 if(Math.abs(this.elemBox.offsetRight) >= this.elemHeight){ this.elemBox.style.right = 0; }else{ this.elemBox.style.right = this.elemBox.offsetRight + this.speed + 'px'; } break; default: // 默认向上滚动，如果滚动的盒子的top超出元素的高度，则置为0 if(Math.abs(this.elemBox.offsetTop) >= this.elemHeight){ this.elemBox.style.top = 0; }else{ this.elemBox.style.top = this.elemBox.offsetTop + speed + 'px'; } } } stopRoll(){ clearInterval(this.scrollTimer) } startRoll(){ this.scrollTimer = setInterval(this.roll,this.time) } }