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所谓的倾斜结果，我也不知怎样用言语形貌，那就直接看Demo啦，下面我们会对这个结果的完成道理逐渐剖析：
http://codepen.io/CodingMonkeyzh/pen/jPYNyr
文档组织
对一个图片增加该结果，起首，我们须要一个具有宽高的容器。DOM 组织异常简朴。
<div class="container">
<img class="tilt-effect" src="http://placehold.it/500x300" alt="" />
</div>
上面这段组织经由剧本处置惩罚以后，会被替换成下面的组织：
<div class="container">
<div class="tilt">
<div class="tilt__back" style="background-image: url(http://placehold.it/500x300);"></div>
<div class="tilt__front" style="opacity: 0.7; -webkit-transform: perspective(1000px) translate3d(0px, 0px, 0px) rotate3d(1, 1, 1, 0deg); transform: perspective(1000px) translate3d(0px, 0px, 0px) rotate3d(1, 1, 1, 0deg); background-image: url(http://placehold.it/500x300);"></div>
<div class="tilt__front" style="opacity: 0.7; -webkit-transform: perspective(1000px) translate3d(0px, 0px, 0px) rotate3d(1, 1, 1, 0deg); transform: perspective(1000px) translate3d(0px, 0px, 0px) rotate3d(1, 1, 1, 0deg); background-image: url(http://placehold.it/500x300);"></div>
</div>
</div>
剧本剖析
我们利用了filtfx.js这个插件对上面的图片举行处置惩罚， 来完成倾斜结果。我在本来的代码中加入了一些解释，来协助我们明白。下面我们对该插件的中心代码举行剖析。
function TiltFx(el, options) {
this.el = el;
this.options = extend({}, this.options);
extend(this.options, options);
this._init();
this._initEvents();
}
这是组织函数，假如我们的文档中，加入了上面的插件，那末插件会遍历文档中具有tilt-effet的img元素，来挪用组织函数TiltFx()：
function init() {
// 遍历一切具有‘title-effect’类的img元素
[].slice.call(document.querySelectorAll('img.tilt-effect')).forEach(function(img) {
new TiltFx(img, JSON.parse(img.getAttribute('data-tilt-options')));
});
}
TiltFx()具有一个原型属性，两个原型要领。原型属性设置了一些默许的参数用于挪用：
/**
* 默许参数
*/
TiltFx.prototype.options = {
extraImgs: 2, // 分外的辅佐图片数目
opacity: 0.7,
bgfixed: true, // 底图是不是牢固
movement: { // 这是一些用于挪动的参数
perspective: 1000,
translateX: -10,
translateY: -10,
translateZ: 20,
rotateX: 2,
rotateY: 2,
rotateZ: 0
}
}
第一个原型要领是_init()，用于初始化DOM结点，天生我们的目的DOM结点：
TiltFx.prototype._init = function() {
this.tiltWrapper = document.createElement('div');
this.tiltWrapper.className = 'tilt';
// main image element.
this.tiltImgBack = document.createElement('div');
this.tiltImgBack.className = 'tilt__back';
this.tiltImgBack.style.backgroundImage = 'url(' + this.el.src + ')';
this.tiltWrapper.appendChild(this.tiltImgBack);
// image elements limit.
if (this.options.extraImgs < 1) {
this.options.extraImgs = 1;
} else if (this.options.extraImgs > 5) {
this.options.extraImgs = 5;
}
if (!this.options.movement.perspective) {
this.options.movement.perspective = 0;
}
// add the extra image elements.
this.imgElems = [];
for (var i = 0; i < this.options.extraImgs; ++i) {
var el = document.createElement('div');
el.className = 'tilt__front';
el.style.backgroundImage = 'url(' + this.el.src + ')';
el.style.opacity = this.options.opacity;
this.tiltWrapper.appendChild(el);
this.imgElems.push(el);
}
if (!this.options.bgfixed) {
this.imgElems.push(this.tiltImgBack);
++this.options.extraImgs;
}
// add it to the DOM and remove original img element.
this.el.parentNode.insertBefore(this.tiltWrapper, this.el);
this.el.parentNode.removeChild(this.el);
// tiltWrapper properties: width/height/left/top
this.view = {
width: this.tiltWrapper.offsetWidth,
height: this.tiltWrapper.offsetHeight
};
};
别的一个原型体式格局是用于监听鼠标事宜之类的：
TiltFx.prototype._initEvents = function() {
var self = this,
moveOpts = self.options.movement;
// mousemove event..
this.tiltWrapper.addEventListener('mousemove', function(ev) {
requestAnimationFrame(function() {
// mouse position relative to the document.
var mousepos = getMousePos(ev),
// document scrolls.
docScrolls = {
left: document.body.scrollLeft + document.documentElement.scrollLeft,
top: document.body.scrollTop + document.documentElement.scrollTop
},
bounds = self.tiltWrapper.getBoundingClientRect(),
// mouse position relative to the main element (tiltWrapper).
relmousepos = {
x: mousepos.x - bounds.left - docScrolls.left,
y: mousepos.y - bounds.top - docScrolls.top
};
// configure the movement for each image element.
for (var i = 0, len = self.imgElems.length; i < len; ++i) {
var el = self.imgElems[i],
rotX = moveOpts.rotateX ? 2 * ((i + 1) * moveOpts.rotateX / self.options.extraImgs) / self.view.height * relmousepos.y - ((i + 1) * moveOpts.rotateX / self.options.extraImgs) : 0,
rotY = moveOpts.rotateY ? 2 * ((i + 1) * moveOpts.rotateY / self.options.extraImgs) / self.view.width * relmousepos.x - ((i + 1) * moveOpts.rotateY / self.options.extraImgs) : 0,
rotZ = moveOpts.rotateZ ? 2 * ((i + 1) * moveOpts.rotateZ / self.options.extraImgs) / self.view.width * relmousepos.x - ((i + 1) * moveOpts.rotateZ / self.options.extraImgs) : 0,
transX = moveOpts.translateX ? 2 * ((i + 1) * moveOpts.translateX / self.options.extraImgs) / self.view.width * relmousepos.x - ((i + 1) * moveOpts.translateX / self.options.extraImgs) : 0,
transY = moveOpts.translateY ? 2 * ((i + 1) * moveOpts.translateY / self.options.extraImgs) / self.view.height * relmousepos.y - ((i + 1) * moveOpts.translateY / self.options.extraImgs) : 0,
transZ = moveOpts.translateZ ? 2 * ((i + 1) * moveOpts.translateZ / self.options.extraImgs) / self.view.height * relmousepos.y - ((i + 1) * moveOpts.translateZ / self.options.extraImgs) : 0;
el.style.WebkitTransform = 'perspective(' + moveOpts.perspective + 'px) translate3d(' + transX + 'px,' + transY + 'px,' + transZ + 'px) rotate3d(1,0,0,' + rotX + 'deg) rotate3d(0,1,0,' + rotY + 'deg) rotate3d(0,0,1,' + rotZ + 'deg)';
el.style.transform = 'perspective(' + moveOpts.perspective + 'px) translate3d(' + transX + 'px,' + transY + 'px,' + transZ + 'px) rotate3d(1,0,0,' + rotX + 'deg) rotate3d(0,1,0,' + rotY + 'deg) rotate3d(0,0,1,' + rotZ + 'deg)';
}
});
});
// reset all when mouse leaves the main wrapper.
this.tiltWrapper.addEventListener('mouseleave', function(ev) {
setTimeout(function() {
for (var i = 0, len = self.imgElems.length; i < len; ++i) {
var el = self.imgElems[i];
el.style.WebkitTransform = 'perspective(' + moveOpts.perspective + 'px) translate3d(0,0,0) rotate3d(1,1,1,0deg)';
el.style.transform = 'perspective(' + moveOpts.perspective + 'px) translate3d(0,0,0) rotate3d(1,1,1,0deg)';
}
}, 60);
});
// window resize
window.addEventListener('resize', throttle(function(ev) {
// recalculate tiltWrapper properties: width/height/left/top
self.view = {
width: self.tiltWrapper.offsetWidth,
height: self.tiltWrapper.offsetHeight
};
}, 50));
};
我们能够看到，监听mousemove的事宜处置惩罚函数中的盘算比较复杂，症结的部份就是在这里：
var el = self.imgElems[i],
rotX = moveOpts.rotateX ? 2 * ((i + 1) * moveOpts.rotateX / self.options.extraImgs) / self.view.height * relmousepos.y - ((i + 1) * moveOpts.rotateX / self.options.extraImgs) : 0,
rotY = moveOpts.rotateY ? 2 * ((i + 1) * moveOpts.rotateY / self.options.extraImgs) / self.view.width * relmousepos.x - ((i + 1) * moveOpts.rotateY / self.options.extraImgs) : 0,
rotZ = moveOpts.rotateZ ? 2 * ((i + 1) * moveOpts.rotateZ / self.options.extraImgs) / self.view.width * relmousepos.x - ((i + 1) * moveOpts.rotateZ / self.options.extraImgs) : 0,
transX = moveOpts.translateX ? 2 * ((i + 1) * moveOpts.translateX / self.options.extraImgs) / self.view.width * relmousepos.x - ((i + 1) * moveOpts.translateX / self.options.extraImgs) : 0,
transY = moveOpts.translateY ? 2 * ((i + 1) * moveOpts.translateY / self.options.extraImgs) / self.view.height * relmousepos.y - ((i + 1) * moveOpts.translateY / self.options.extraImgs) : 0,
transZ = moveOpts.translateZ ? 2 * ((i + 1) * moveOpts.translateZ / self.options.extraImgs) / self.view.height * relmousepos.y - ((i + 1) * moveOpts.translateZ / self.options.extraImgs) : 0;
el.style.WebkitTransform = 'perspective(' + moveOpts.perspective + 'px) translate3d(' + transX + 'px,' + transY + 'px,' + transZ + 'px) rotate3d(1,0,0,' + rotX + 'deg) rotate3d(0,1,0,' + rotY + 'deg) rotate3d(0,0,1,' + rotZ + 'deg)';
el.style.transform = 'perspective(' + moveOpts.perspective + 'px) translate3d(' + transX + 'px,' + transY + 'px,' + transZ + 'px) rotate3d(1,0,0,' + rotX + 'deg) rotate3d(0,1,0,' + rotY + 'deg) rotate3d(0,0,1,' + rotZ + 'deg)';
这里我们依据鼠标的位置，盘算出了各个图层对应的偏移量和扭转角度，然后对它们举行变更即可。
末了mouseleave以后，我们再把个个图层恢复到初始位置就好了。
