js实现商品抛物线加入购物车特效

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本文实例为大家分享了js实现商品抛物线加入购物车动画代码,供大家参考,具体内容如下

var defaults = {
speed: 166.67,// 每帧移动的像素大小,每帧(对于大部分显示屏)大约16~17毫秒
curvature: 0.001,// 实际指焦点到准线的距离,你可以抽象成曲率,这里模拟扔物体的抛物线,因此是开口向下的
progress: function() {},complete: function() {}
};

var params = {}; options = options || {};

for (var key in defaults) {
params[key] = options[key] || defaults[key];
}

var exports = {
mark: function() { return this; },position: function() { return this; },move: function() { return this; },init: function() { return this; }
};

/* 确定移动的方式

  • IE6-IE8 是margin位移
  • IE9+使用transform
    */
    var moveStyle = "margin",testDiv = document.createElement("div");
    if ("oninput" in testDiv) {
    ["","ms","webkit"].forEach(function(prefix) {
    var transform = prefix + (prefix? "T": "t") + "ransform";
    if (transform in testDiv.style) {
    moveStyle = transform;
    }
    });
    }

// 根据两点坐标以及曲率确定运动曲线函数(也就是确定a,b的值)
/ 公式: y = axx + bx + c;
*/
var a = params.curvature,b = 0,c = 0;

// 是否执行运动的标志量
var flagMove = true;

if (element && target && element.nodeType == 1 && target.nodeType == 1) {
var rectElement = {},rectTarget = {};

// 移动元素的中心点位置,目标元素的中心点位置
var centerElement = {},centerTarget = {};

// 目标元素的坐标位置
var coordElement = {},coordTarget = {};

// 标注当前元素的坐标
exports.mark = function() {
  if (flagMove == false) return this;
  if (typeof coordElement.x == "undefined") this.position();
  element.setAttribute("data-center",[coordElement.x,coordElement.y].join());
  target.setAttribute("data-center",[coordTarget.x,coordTarget.y].join());
  return this;
}

exports.position = function() {
  if (flagMove == false) return this;

  var scrollLeft = document.documentElement.scrollLeft || document.body.scrollLeft,scrollTop = document.documentElement.scrollTop || document.body.scrollTop;

  // 初始位置
  if (moveStyle == "margin") {
    element.style.marginLeft = element.style.marginTop = "0px";
  } else {
    element.style[moveStyle] = "translate(0,0)";
  }

  // 四边缘的坐标
  rectElement = element.getBoundingClientRect();
  rectTarget = target.getBoundingClientRect();

  // 移动元素的中心点坐标
  centerElement = {
    x: rectElement.left + (rectElement.right - rectElement.left) / 2 + scrollLeft,y: rectElement.top + (rectElement.bottom - rectElement.top) / 2  + scrollTop
  };

  // 目标元素的中心点位置
  centerTarget = {
    x: rectTarget.left + (rectTarget.right - rectTarget.left) / 2 + scrollLeft,y: rectTarget.top + (rectTarget.bottom - rectTarget.top) / 2 + scrollTop    
  };

  // 转换成相对坐标位置
  coordElement = {
    x: 0,y: 0  
  };
  coordTarget = {
    x: -1 * (centerElement.x - centerTarget.x),y: -1 * (centerElement.y - centerTarget.y)  
  };

  /*
   * 因为经过(0,0),因此c = 0
   * 于是:
   * y = a * x*x + b*x;
   * y1 = a * x1*x1 + b*x1;
   * y2 = a * x2*x2 + b*x2;
   * 利用第二个坐标:
   * b = (y2+ a*x2*x2) / x2
  */
  // 于是
  b = (coordTarget.y - a * coordTarget.x * coordTarget.x) / coordTarget.x;  

  return this;
};    

// 按照这个曲线运动
exports.move = function() {
  // 如果曲线运动还没有结束,不再执行新的运动
  if (flagMove == false) return this;

  var startx = 0,rate = coordTarget.x > 0? 1: -1;

  var step = function() {
    // 切线 y'=2ax+b
    var tangent = 2 * a * startx + b; // = y / x
    // y*y + x*x = speed
    // (tangent * x)^2 + x*x = speed
    // x = Math.sqr(speed / (tangent * tangent + 1));
    startx = startx + rate * Math.sqrt(params.speed / (tangent * tangent + 1));

    // 防止过界
    if ((rate == 1 && startx > coordTarget.x) || (rate == -1 && startx < coordTarget.x)) {
      startx = coordTarget.x;
    }
    var x = startx,y = a * x * x + b * x;

    // <a href="/tag/biaoji/" target="_blank" class="keywords">标记</a>当前位置,这里有测试使用的嫌疑,实际使用可以将这一行注释
    element.setAttribute("data-center",[Math.round(x),Math.round(y)].join());

    // x,y目前是坐标,需要转换成定位的像素值
    if (moveStyle == "margin") {
      element.style.marginLeft = x + "px";
      element.style.marginTop = y + "px";
    } else {
      element.style[moveStyle] = "translate("+ [x + "px",y + "px"].join() +")";
    }

    if (startx !== coordTarget.x) {
      params.progress(x,y);
      window.requestAnimationFrame(step);  
    } else {
      // 运动结束,回调执行
      params.complete();
      flagMove = true;  
    }
  };
  window.requestAnimationFrame(step);
  flagMove = false;

  return this;
};

// 初始化<a href="/tag/fangfa/" target="_blank" class="keywords">方法</a>
exports.init = function() {
  this.position().mark().move();
};

}

return exports;
};

/*! requestAnimationFrame.js

  • by zhangxinxu 2013-09-30
    */
    (function() {
    var lastTime = 0;
    var vendors = ['webkit','moz'];
    for(var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
    window.requestAnimationFrame = window[vendors[x] + 'RequestAnimationFrame'];
    window.cancelAnimationFrame = window[vendors[x] + 'CancelAnimationFrame'] || // name has changed in Webkit
    window[vendors[x] + 'CancelRequestAnimationFrame'];
    }

if (!window.requestAnimationFrame) {
window.requestAnimationFrame = function(callback,element) {
var currTime = new Date().getTime();
var timeToCall = Math.max(0,16.7 - (currTime - lastTime));
var id = window.setTimeout(function() {
callback(currTime + timeToCall);
},timeToCall);
lastTime = currTime + timeToCall;
return id;
};
}
if (!window.cancelAnimationFrame) {
window.cancelAnimationFrame = function(id) {
clearTimeout(id);
};
}
}());

使用:

标记 var parabola = funParabola(element,target).mark(); // 抛物线运动的触发 document.body.onclick = function() { element.style.marginLeft = "0px"; element.style.marginTop = "0px"; parabola.init(); };

加入购物车实战:

// 元素以及其他一些变量
var eleFlyElement = document.querySelector("#flyItem"),eleShopCart = document.querySelector("#shopCart");
var numberItem = 0;
// 抛物线运动
var myParabola = funParabola(eleFlyElement,eleShopCart,{
speed: 400,curvature: 0.002,complete: function() {
eleFlyElement.style.visibility = "hidden";
eleShopCart.querySelector("span").innerHTML = ++numberItem;
}
});
// 绑定点击事件
if (eleFlyElement && eleShopCart) {
[].slice.call(document.getElementsByClassName("btnCart")).forEach(function(button) {
button.addEventListener("click",function() {
// 滚动大小
var scrollLeft = document.documentElement.scrollLeft || document.body.scrollLeft || 0,scrollTop = document.documentElement.scrollTop || document.body.scrollTop || 0;

  eleFlyElement.style.left = event.clientX + scrollLeft + "px";
  eleFlyElement.style.top = event.clientY + scrollTop + "px";
  eleFlyElement.style.visibility = "visible";

  // 需要重定位
  myParabola.position().move(); 
});

});
}

以上就是本文的全部内容,希望对大家的学习有所帮助。

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