移动端单击图片放大缩小

移动端单击图片放大，缩小

<!DOCTYPE html>
<html>

<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no" />
<title>图片缩放</title>
<link rel="stylesheet" type="text/css" href="scale.css" />
<script src="../../js/scale.js" type="text/javascript" charset="utf-8"></script>
<style type="text/css">
.list img{
width: 200px;
height: 200px;
}
/*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%;
}
</style>
</head>

<body>
<div class="list">
<img src="../../img/biyadi.jpg" />
<img src="../../img/biyadi.jpg" />
</div>
<section class="imgzoom_pack">
<div class="imgzoom_x">X</div>
<div class="imgzoom_img"><img src="" /></div>
</section>
<script src="scale.js" type="text/javascript" charset="utf-8"></script>
<script type="text/javascript">
document.addEventListener("DOMContentLoaded", function(event) {
ImagesZoom.init({
"elem": ".list"
});
}, false);
</script>
</body>

</html>

 

 

js部分  scale.js

  1 (function(window, undefined){
  2 var document = window.document,
  3 support = {
  4 transform3d: ("WebKitCSSMatrix" in window && "m11" in new WebKitCSSMatrix()),
  5 touch: ("ontouchstart" in window)
  6 };
  7 
  8 function getTranslate(x, y){
  9 var distX = x, distY = y;
 10 return support.transform3d ? "translate3d("+ distX +"px, "+ distY +"px, 0)" : "translate("+ distX +"px, "+ distY +"px)";
 11 }
 12 
 13 
 14 function getPage(event, page) {
 15 return support.touch ? event.changedTouches[0][page] : event[page];
 16 }
 17 
 18 
 19 var ImagesZoom = function(){};
 20 
 21 
 22 ImagesZoom.prototype = {
 23 // 给初始化数据
 24 init: function(param){
 25 var self = this,
 26 params = param || {};
 27 
 28 var imgList = document.querySelectorAll(params.elem + " img"),
 29 zoomMask = document.querySelector(".imgzoom_pack"),
 30 zoomImg = document.querySelector(".imgzoom_pack .imgzoom_img img"),
 31 zoomClose = document.querySelector(".imgzoom_pack .imgzoom_x"),
 32 imgSrc = "";
 33 
 34 
 35 self.buffMove = 3; //缓冲系数
 36 self.buffScale = 2; //放大系数
 37 self.finger = false; //触摸手指的状态 false：单手指 true：多手指
 38 
 39 self._destroy();
 40 
 41 
 42 zoomClose.addEventListener("click", function(){
 43 zoomMask.style.cssText = "display:none";
 44 zoomImg.src = "";
 45 zoomImg.style.cssText = "";
 46 
 47 
 48 self._destroy();
 49 
 50 
 51 document.removeEventListener("touchmove", self.eventStop, false);
 52 }, false);
 53 
 54 
 55 for(var len=imgList.length,i=0; i<len; i++){
 56 imgList[i].addEventListener("click", function(){
 57 imgSrc = this.getAttribute("src");
 58 zoomMask.style.cssText = "display:block";
 59 zoomImg.src = imgSrc;
 60 
 61 
 62 zoomImg.onload = function(){
 63 zoomImg.style.cssText = "margin-top:-"+(zoomImg.offsetHeight/2)+"px";
 64 
 65 
 66 // 禁止页面滚动
 67 document.addEventListener("touchmove", self.eventStop, false);
 68 
 69 self.imgBaseWidth = zoomImg.offsetWidth;
 70 self.imgBaseHeight = zoomImg.offsetHeight;
 71 
 72 
 73 self.addEventStart({
 74 wrapX: zoomMask.offsetWidth,
 75 wrapY: zoomMask.offsetHeight,
 76 mapX: zoomImg.width,
 77 mapY: zoomImg.height
 78 });
 79 }
 80 }, false);
 81 }
 82 },
 83 addEventStart: function(param){
 84 var self = this,
 85 params = param || {};
 86 
 87 
 88 self.element = document.querySelector(".imgzoom_pack img");
 89 
 90 
 91 //config set
 92 self.wrapX = params.wrapX || 0; //可视区域宽度
 93 self.wrapY = params.wrapY || 0; //可视区域高度
 94 self.mapX = params.mapX || 0; //地图宽度
 95 self.mapY = params.mapY || 0; //地图高度
 96 
 97 
 98 self.outDistY = (self.mapY - self.wrapY)/2; //图片超过一屏的时候有用
 99 
100 self.width = self.mapX - self.wrapX; //地图的宽度减去可视区域的宽度
101 self.height = self.mapY - self.wrapY; //地图的高度减去可视区域的高度
102 
103 
104 self.element.addEventListener("touchstart",function(e){
105 self._touchstart(e);
106 },false);
107 self.element.addEventListener("touchmove",function(e){
108 self._touchmove(e);
109 },false);
110 self.element.addEventListener("touchend",function(e){
111 self._touchend(e);
112 },false);
113 },
114 // 重置坐标数据
115 _destroy: function(){
116 this.distX = 0;
117 this.distY = 0;
118 this.newX = 0;
119 this.newY = 0;
120 },
121 // 更新地图信息
122 _changeData: function(){
123 this.mapX = this.element.offsetWidth; //地图宽度
124 this.mapY = this.element.offsetHeight; //地图高度
125 // 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
126 this.width = this.mapX - this.wrapX; //地图的宽度减去可视区域的宽度
127 this.height = this.mapY - this.wrapY; //地图的高度减去可视区域的高度
128 },
129 _touchstart: function(e){
130 var self = this;
131 
132 
133 e.preventDefault();
134 
135 
136 var touchTarget = e.targetTouches.length; //获得触控点数
137 
138 
139 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
140 
141 
142 if(touchTarget == 1){
143 // 获取开始坐标
144 self.basePageX = getPage(e, "pageX");
145 self.basePageY = getPage(e, "pageY");
146 
147 
148 self.finger = false;
149 }else{
150 self.finger = true;
151 
152 
153 self.startFingerDist = self.getTouchDist(e).dist;
154 self.startFingerX = self.getTouchDist(e).x;
155 self.startFingerY = self.getTouchDist(e).y;
156 }
157 
158 
159 console.log("pageX: "+getPage(e, "pageX"));
160 console.log("pageY: "+getPage(e, "pageY"));
161 },
162 _touchmove: function(e){
163 var self = this;
164 
165 
166 e.preventDefault();
167 e.stopPropagation();
168 
169 
170 console.log("event.changedTouches[0].pageY: "+event.changedTouches[0].pageY);
171 
172 var touchTarget = e.targetTouches.length; //获得触控点数
173 
174 
175 if(touchTarget == 1 && !self.finger){
176 self._move(e);
177 }
178 
179 
180 if(touchTarget>=2){
181 self._zoom(e);
182 }
183 },
184 _touchend: function(e){
185 var self = this;
186 
187 
188 self._changeData(); //重新计算数据
189 if(self.finger){
190 self.distX = -self.imgNewX;
191 self.distY = -self.imgNewY;
192 }
193 
194 
195 if( self.distX>0 ){
196 self.newX = 0;
197 }else if( self.distX<=0 && self.distX>=-self.width ){
198 self.newX = self.distX;
199 self.newY = self.distY;
200 }else if( self.distX<-self.width ){
201 self.newX = -self.width;
202 }
203 self.reset();
204 },
205 _move: function(e){
206 var self = this,
207 pageX = getPage(e, "pageX"), //获取移动坐标
208 pageY = getPage(e, "pageY");
209 
210 
211 // 禁止默认事件
212 // e.preventDefault();
213 // e.stopPropagation();
214 
215 
216 // 获得移动距离
217 self.distX = (pageX - self.basePageX) + self.newX;
218 self.distY = (pageY - self.basePageY) + self.newY;
219 
220 
221 if(self.distX > 0){
222 self.moveX = Math.round(self.distX/self.buffMove);
223 }else if( self.distX<=0 && self.distX>=-self.width ){
224 self.moveX = self.distX;
225 }else if(self.distX < -self.width ){
226 self.moveX = -self.width+Math.round((self.distX+self.width)/self.buffMove);
227 }
228 self.movePos();
229 self.finger = false;
230 },
231 // 图片缩放
232 _zoom: function(e){
233 var self = this;
234 // e.preventDefault();
235 // e.stopPropagation();
236 
237 
238 var nowFingerDist = self.getTouchDist(e).dist, //获得当前长度
239 ratio = nowFingerDist / self.startFingerDist, //计算缩放比
240 imgWidth = Math.round(self.mapX * ratio), //计算图片宽度
241 imgHeight = Math.round(self.mapY * ratio); //计算图片高度
242 
243 
244 // 计算图片新的坐标
245 self.imgNewX = Math.round(self.startFingerX * ratio - self.startFingerX - self.newX * ratio);
246 self.imgNewY = Math.round((self.startFingerY * ratio - self.startFingerY)/2 - self.newY * ratio);
247 
248 
249 if(imgWidth >= self.imgBaseWidth){
250 self.element.style.width = imgWidth + "px";
251 self.refresh(-self.imgNewX, -self.imgNewY, "0s", "ease");
252 self.finger = true;
253 }else{
254 if(imgWidth < self.imgBaseWidth){
255 self.element.style.width = self.imgBaseWidth + "px";
256 }
257 }
258 
259 
260 self.finger = true;
261 },
262 // 移动坐标
263 movePos: function(){
264 var self = this;
265 
266 
267 if(self.height<0){
268 if(self.element.offsetWidth == self.imgBaseWidth){
269 self.moveY = Math.round(self.distY/self.buffMove);
270 }else{
271 var moveTop = Math.round((self.element.offsetHeight-self.imgBaseHeight)/2);
272 self.moveY = -moveTop + Math.round((self.distY + moveTop)/self.buffMove);
273 }
274 }else{
275 var a = Math.round((self.wrapY - self.imgBaseHeight)/2),
276 b = self.element.offsetHeight - self.wrapY + Math.round(self.wrapY - self.imgBaseHeight)/2;
277 
278 
279 if(self.distY >= -a){
280 self.moveY = Math.round((self.distY + a)/self.buffMove) - a;
281 }else if(self.distY <= -b){
282 self.moveY = Math.round((self.distY + b)/self.buffMove) - b;
283 }else{
284 self.moveY = self.distY;
285 }
286 }
287 self.refresh(self.moveX, self.moveY, "0s", "ease");
288 },
289 // 重置数据
290 reset: function(){
291 var self = this,
292 hideTime = ".2s";
293 if(self.height<0){
294 self.newY = -Math.round(self.element.offsetHeight - self.imgBaseHeight)/2;
295 }else{
296 var a = Math.round((self.wrapY - self.imgBaseHeight)/2),
297 b = self.element.offsetHeight - self.wrapY + Math.round(self.wrapY - self.imgBaseHeight)/2;
298 
299 
300 if(self.distY >= -a){
301 self.newY = -a;
302 }else if(self.distY <= -b){
303 self.newY = -b;
304 }else{
305 self.newY = self.distY;
306 }
307 }
308 self.refresh(self.newX, self.newY, hideTime, "ease-in-out");
309 },
310 // 执行图片移动
311 refresh: function(x, y, timer, type){
312 this.element.style.webkitTransitionProperty = "-webkit-transform";
313 this.element.style.webkitTransitionDuration = timer;
314 this.element.style.webkitTransitionTimingFunction = type;
315 this.element.style.webkitTransform = getTranslate(x, y);
316 },
317 // 获取多点触控
318 getTouchDist: function(e){
319 var x1 = 0,
320 y1 = 0,
321 x2 = 0,
322 y2 = 0,
323 x3 = 0,
324 y3 = 0,
325 result = {};
326 
327 
328 x1 = e.touches[0].pageX;
329 x2 = e.touches[1].pageX;
330 y1 = e.touches[0].pageY - document.body.scrollTop;
331 y2 = e.touches[1].pageY - document.body.scrollTop;
332 
333 
334 if(!x1 || !x2) return;
335 
336 
337 if(x1<=x2){
338 x3 = (x2-x1)/2+x1;
339 }else{
340 x3 = (x1-x2)/2+x2;
341 }
342 if(y1<=y2){
343 y3 = (y2-y1)/2+y1;
344 }else{
345 y3 = (y1-y2)/2+y2;
346 }
347 
348 
349 result = {
350 dist: Math.round(Math.sqrt(Math.pow(x1-x2,2)+Math.pow(y1-y2,2))),
351 x: Math.round(x3),
352 y: Math.round(y3)
353 };
354 return result;
355 },
356 eventStop: function(e){
357 e.preventDefault();
358 e.stopPropagation();
359 }
360 };
361 
362 
363 window.ImagesZoom = new ImagesZoom();
364 })(this);

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原文地址：https://www.cnblogs.com/cyhsmile/p/11212278.html