手机上图片的放大缩小处理 touch——zoom

手机上滑动放大缩小图片的处理

文件目录

html部分 index.html

    
        
        
        
        
    
    
		
    	

    		

    		

            

    		

    	
		
    	

    		
X
    		

    	
        
		
    

css部分  scale.css

/**rest**/
body, ul, li, section, div{
	padding:0;
	margin:0;
}
body{
	font-family:Arial,Roboto,'Droid Sans','Hiragino Sans GB',STXihei,'sans-serif';
	width:100%;
	-webkit-user-select:none;
	-webkit-touch-callout:none;
	-webkit-tap-highlight-color:rgba(0,0,0,0);
	-webkit-text-size-adjust:none;
}
ul,li{
	list-style:none;
}
img{
	border:0;
}

.list{
	width:100%;
	padding:10px 0;
}
.list li{
	display:block;
	margin-bottom:10px;
	box-shadow:0 1px 2px rgba(0,0,0,.1), 0 -1px 2px rgba(0,0,0,.1);
}
.list li img{
	width:100%;
	height:auto;
}



/*弹框样式*/
.imgzoom_pack{
	width:100%;
	height:100%;
	position:fixed;
	left:0;
	top:0;
	background:rgba(0,0,0,.6);
	display:none;
}
.imgzoom_pack .imgzoom_x{
	color:#fff;
	height:30px;
	width:30px;
	line-height:30px;
	background:#000;
	text-align:center;
	position:absolute;
	right:5px;
	top:5px;
	z-index:10;
	cursor:pointer;
}
.imgzoom_pack .imgzoom_img{
	width:100%;
	height:100%;
	position:absolute;
	left:0;
	top:0;
	overflow:hidden;
}
.imgzoom_pack .imgzoom_img img{
	width:100%;
	position:absolute;
	top:50%;
}

js部分  scale.js

(function(window, undefined){
var document = window.document,
support = {
transform3d: ("WebKitCSSMatrix" in window && "m11" in new WebKitCSSMatrix()),
touch: ("ontouchstart" in window)
};

function getTranslate(x, y){
var distX = x, distY = y;
return support.transform3d ? "translate3d("+ distX +"px, "+ distY +"px, 0)" : "translate("+ distX +"px, "+ distY +"px)";
}


function getPage(event, page) {
return support.touch ? event.changedTouches[0][page] : event[page];
}


var ImagesZoom = function(){};


ImagesZoom.prototype = {
// 给初始化数据
init: function(param){
var self   = this,
params = param || {};

var imgList   = document.querySelectorAll(params.elem + " img"),
zoomMask  = document.querySelector(".imgzoom_pack"),
zoomImg   = document.querySelector(".imgzoom_pack .imgzoom_img img"),
zoomClose = document.querySelector(".imgzoom_pack .imgzoom_x"),
imgSrc    = "";


self.buffMove   = 3; //缓冲系数
self.buffScale  = 2; //放大系数
self.finger = false; //触摸手指的状态 false：单手指 true：多手指

self._destroy();


zoomClose.addEventListener("click", function(){
zoomMask.style.cssText = "display:none";
zoomImg.src = "";
zoomImg.style.cssText = "";


self._destroy();


document.removeEventListener("touchmove", self.eventStop, false);
}, false);


for(var len=imgList.length,i=0; iimgList[i].addEventListener("click", function(){
imgSrc = this.getAttribute("src");
zoomMask.style.cssText = "display:block";
zoomImg.src = imgSrc;


zoomImg.onload = function(){
zoomImg.style.cssText = "margin-top:-"+(zoomImg.offsetHeight/2)+"px";


// 禁止页面滚动
document.addEventListener("touchmove", self.eventStop, false);

self.imgBaseWidth  = zoomImg.offsetWidth;
self.imgBaseHeight = zoomImg.offsetHeight;


self.addEventStart({
wrapX: zoomMask.offsetWidth,
wrapY: zoomMask.offsetHeight,
mapX: zoomImg.width,
mapY: zoomImg.height
});
}
}, false);
}
},
addEventStart: function(param){
var self   = this,
params = param || {};


self.element = document.querySelector(".imgzoom_pack img");


//config set
self.wrapX = params.wrapX || 0; //可视区域宽度
self.wrapY = params.wrapY || 0; //可视区域高度
self.mapX  = params.mapX || 0;    //地图宽度
self.mapY  = params.mapY || 0;      //地图高度


self.outDistY = (self.mapY - self.wrapY)/2; //图片超过一屏的时候有用

self.width  = self.mapX - self.wrapX;   //地图的宽度减去可视区域的宽度
self.height = self.mapY - self.wrapY;   //地图的高度减去可视区域的高度


self.element.addEventListener("touchstart",function(e){
self._touchstart(e);
},false);
self.element.addEventListener("touchmove",function(e){
self._touchmove(e);
},false);
self.element.addEventListener("touchend",function(e){
self._touchend(e);
},false);
},
// 重置坐标数据
_destroy: function(){
this.distX = 0;
this.distY = 0;
this.newX  = 0;
this.newY  = 0;
},
// 更新地图信息
_changeData: function(){
this.mapX     = this.element.offsetWidth;  //地图宽度
this.mapY     = this.element.offsetHeight;      //地图高度
// this.outDistY = (this.mapY - this.wrapY)/2; //当图片高度超过屏幕的高度时候。图片是垂直居中的，这时移动有个高度做为缓冲带
this.width    = this.mapX - this.wrapX;   //地图的宽度减去可视区域的宽度
this.height   = this.mapY - this.wrapY;   //地图的高度减去可视区域的高度
},
_touchstart: function(e){
var self = this;


e.preventDefault();


var touchTarget = e.targetTouches.length; //获得触控点数


self._changeData(); //重新初始化图片、可视区域数据，由于放大会产生新的计算


if(touchTarget == 1){
// 获取开始坐标
self.basePageX = getPage(e, "pageX");
self.basePageY = getPage(e, "pageY");


self.finger = false;
}else{
self.finger = true;


self.startFingerDist = self.getTouchDist(e).dist;
self.startFingerX    = self.getTouchDist(e).x;
self.startFingerY    = self.getTouchDist(e).y;
}


console.log("pageX: "+getPage(e, "pageX"));
console.log("pageY: "+getPage(e, "pageY"));
},
_touchmove: function(e){
var self = this;


e.preventDefault();
e.stopPropagation();


console.log("event.changedTouches[0].pageY: "+event.changedTouches[0].pageY);

var touchTarget = e.targetTouches.length; //获得触控点数


if(touchTarget == 1 && !self.finger){
self._move(e);
}


if(touchTarget>=2){
self._zoom(e);
}
},
_touchend: function(e){
var self = this;


self._changeData(); //重新计算数据
if(self.finger){
self.distX = -self.imgNewX;
self.distY = -self.imgNewY;
}


if( self.distX>0 ){
self.newX = 0;
}else if( self.distX<=0 && self.distX>=-self.width ){
self.newX = self.distX;
self.newY = self.distY;
}else if( self.distX<-self.width ){
self.newX = -self.width;
}
self.reset();
},
_move: function(e){
var self = this,
pageX = getPage(e, "pageX"), //获取移动坐标
pageY = getPage(e, "pageY");


// 禁止默认事件
// e.preventDefault();
// e.stopPropagation();


// 获得移动距离
self.distX = (pageX - self.basePageX) + self.newX;
self.distY = (pageY - self.basePageY) + self.newY;


if(self.distX > 0){
self.moveX = Math.round(self.distX/self.buffMove);
}else if( self.distX<=0 && self.distX>=-self.width ){
self.moveX = self.distX;
}else if(self.distX < -self.width ){
self.moveX = -self.width+Math.round((self.distX+self.width)/self.buffMove);
}
self.movePos();
self.finger = false;
},
// 图片缩放
_zoom: function(e){
var self = this;
// e.preventDefault();
// e.stopPropagation();


var nowFingerDist = self.getTouchDist(e).dist, //获得当前长度
ratio  = nowFingerDist / self.startFingerDist, //计算缩放比
imgWidth    = Math.round(self.mapX * ratio), //计算图片宽度
imgHeight  = Math.round(self.mapY * ratio); //计算图片高度


// 计算图片新的坐标
self.imgNewX = Math.round(self.startFingerX * ratio - self.startFingerX - self.newX * ratio);
self.imgNewY = Math.round((self.startFingerY * ratio - self.startFingerY)/2 - self.newY * ratio);


if(imgWidth >= self.imgBaseWidth){
self.element.style.width = imgWidth + "px";
self.refresh(-self.imgNewX, -self.imgNewY, "0s", "ease");
self.finger = true;
}else{
if(imgWidth < self.imgBaseWidth){
self.element.style.width = self.imgBaseWidth + "px";
}
}


self.finger = true;
},
// 移动坐标
movePos: function(){
var self = this;


if(self.height<0){
if(self.element.offsetWidth == self.imgBaseWidth){
self.moveY = Math.round(self.distY/self.buffMove);
}else{
var moveTop = Math.round((self.element.offsetHeight-self.imgBaseHeight)/2);
self.moveY = -moveTop + Math.round((self.distY + moveTop)/self.buffMove);
}
}else{
var a = Math.round((self.wrapY - self.imgBaseHeight)/2),
b = self.element.offsetHeight - self.wrapY + Math.round(self.wrapY - self.imgBaseHeight)/2;


if(self.distY >= -a){
self.moveY = Math.round((self.distY + a)/self.buffMove) - a;
}else if(self.distY <= -b){
self.moveY = Math.round((self.distY + b)/self.buffMove) - b;
}else{
self.moveY = self.distY;
}
}
self.refresh(self.moveX, self.moveY, "0s", "ease");
},
// 重置数据
reset: function(){
var self = this,
hideTime = ".2s";
if(self.height<0){
self.newY = -Math.round(self.element.offsetHeight - self.imgBaseHeight)/2;
}else{
var a = Math.round((self.wrapY - self.imgBaseHeight)/2),
b = self.element.offsetHeight - self.wrapY + Math.round(self.wrapY - self.imgBaseHeight)/2;


if(self.distY >= -a){
self.newY = -a;
}else if(self.distY <= -b){
self.newY = -b;
}else{
self.newY = self.distY;
}
}
self.refresh(self.newX, self.newY, hideTime, "ease-in-out");
},
// 执行图片移动
refresh: function(x, y, timer, type){
this.element.style.webkitTransitionProperty = "-webkit-transform";
this.element.style.webkitTransitionDuration = timer;
this.element.style.webkitTransitionTimingFunction = type;
this.element.style.webkitTransform = getTranslate(x, y);
},
// 获取多点触控
getTouchDist: function(e){
var x1 = 0,
y1 = 0,
x2 = 0,
y2 = 0,
x3 = 0,
y3 = 0,
result = {};


x1 = e.touches[0].pageX;
x2 = e.touches[1].pageX;
y1 = e.touches[0].pageY - document.body.scrollTop;
y2 = e.touches[1].pageY - document.body.scrollTop;


if(!x1 || !x2) return;


if(x1<=x2){
x3 = (x2-x1)/2+x1;
}else{
x3 = (x1-x2)/2+x2;
}
if(y1<=y2){
y3 = (y2-y1)/2+y1;
}else{
y3 = (y1-y2)/2+y2;
}


result = {
dist: Math.round(Math.sqrt(Math.pow(x1-x2,2)+Math.pow(y1-y2,2))),
x: Math.round(x3),
y: Math.round(y3)
};
return result;
},
eventStop: function(e){
e.preventDefault();
e.stopPropagation();
}
};


window.ImagesZoom = new ImagesZoom();
})(this);