pinchzoom 官网 http://manuelstofer.github.io/pinchzoom/

PortraitClip.css

.pinch-page{position:fixed;top:0;bottom:0;left:0;right:0;display:none;width:100%;height:100%;background-color:#333;z-index:9;}
.pinch-page .top-mask,
.pinch-page .bottom-mask{position:absolute;left:0;top:0;right:0;display:block;background-color:rgba(0,0,0,0.6);z-index: 99;
}.pinch-page .bottom-mask{top:auto;bottom:0;
}.pinch-page .pinch-zoom-container{position:absolute!important;left:0;top:0;bottom:0;right:0;margin:auto;overflow: visible!important;z-index: 9;box-sizing: border-box;
}.pinch-page .pinch-zoom-container:before{content:"";position:absolute;top:0;bottom:0;left:0;right:0;display:block;width:100%;height:100%;z-index:999;border:1px solid #fff;box-sizing: border-box;
}.pinch-page .pinch-zoom{
}.pinch-page .pinch-zoom-p_w_picpath{display:block;width:100%;height:320px;background: no-repeat center center;background-size:contain;
}.pinch-page .operation-bar{position:absolute;left:0;right:0;bottom:0;display:block;height:60px;z-index: 999;background-color:rgba(51,51,51,0.6);
}
.pinch-page .operation-bar .cancel-btn{position:absolute;top:0;bottom:0;left:0;display:block;height:60px;line-height: 60px;font-size:16px;color:#fff;padding:0 20px;
}
.pinch-page .operation-bar .save-btn{position:absolute;top:0;bottom:0;right:0;display:block;height:60px;line-height: 60px;font-size:16px;color:#fff;padding:0 20px;
}

PortraitClip.js

(function($){/* ======================================== 页面渲染 ======================================== *//* ======================================== 不可变字段 ======================================== */var initialized = false; // 是否初始化var container = null;var clientWidth = $(window).width();var clientHeight = $(window).height();var pinchZoomImageWidth = clientWidth;var pinchZoomImageHeight = clientWidth;var maskHeight = (clientHeight-clientWidth)/2;var pinchZoom = null; // pinchZoom 对象/* ======================================== 可变字段 ======================================== */var p_w_picpathWidth = 0;var p_w_picpathHeight = 0;var xOffset = 0;var yOffset = 0;var originScale = 0;var p_w_picpath = null;var callback = null; // 加载完之后的回调// 构建DOMfunction render(){var html =  "<div class='pinch-page'>                                                           "+"  <em class='top-mask'></em>                                                      "+"  <div class='pinch-zoom'>                                                        "+"     <div class='pinch-zoom-p_w_picpath'></div>                                        "+"  </div>                                                                          "+"  <em class='bottom-mask'></em>                                                   "+"  <div class='operation-bar'>                                                     "+"     <a class='cancel-btn'>取消</a>                                              "+"     <a class='save-btn'>选取</a>                                                "+"  </div>                                                                          "+"</div>                                                                             ";$(html).appendTo("body");// 初始化 pinchZoompinchZoom = new RTP.PinchZoom($(".pinch-zoom"));// 添加遮罩$(".pinch-page .top-mask").css("height",maskHeight+"px");$(".pinch-page .bottom-mask").css("height",maskHeight+"px");$(".pinch-zoom-container,.pinch-zoom-p_w_picpath").css({"width":pinchZoomImageWidth+"px","height":pinchZoomImageHeight+"px"});container = $(".pinch-page");}// 绑定事件function bindPageEvents(){container.on("touchend",".save-btn",function(e){e.stopPropagation();e.preventDefault();var transformCss = $(".pinch-zoom").css("-webkit-transform");var positionInfo = retrievePositionInfo(transformCss);clipImage(positionInfo.scale,positionInfo.x,positionInfo.y,callback);$(container).hide();});container.on("touchend",".cancel-btn",function(e){e.stopPropagation();e.preventDefault();$(container).hide();});container.on("touchstart touchmove touchend",function(e){e.stopPropagation();e.preventDefault();});}// 初始化方法function init(){if(initialized){return;}initialized = true;render();bindPageEvents();}/* ======================================== common-method ======================================== */// 刷新 头像剪裁容器function loadImage(originImage,loadCallback){if(!initialized){init();} // 如果未初始化则初始化callback = loadCallback;$(container).find(".pinch-zoom-p_w_picpath").css("background-p_w_picpath","url("+originImage+")");p_w_picpath = new Image();p_w_picpath.onload = function(){p_w_picpathWidth = p_w_picpath.width;p_w_picpathHeight = p_w_picpath.height;loadImageCallback();$(container).show();};p_w_picpath.src=originImage;}// 图像加载回调function loadImageCallback(){if(p_w_picpathWidth>p_w_picpathHeight){yOffset = (p_w_picpathWidth-p_w_picpathHeight)*pinchZoomImageWidth/p_w_picpathWidth/2;originScale = pinchZoomImageWidth/p_w_picpathWidth;}else{xOffset = (p_w_picpathHeight-p_w_picpathWidth)*pinchZoomImageWidth/p_w_picpathHeight/2;originScale = pinchZoomImageHeight/p_w_picpathHeight;}var minZoom = 1;if(xOffset!=0){minZoom = clientWidth/(clientWidth-2*xOffset);}if(yOffset!=0){minZoom = clientWidth/(clientWidth-2*yOffset);}// 初始化 pinchZoom 对戏那个pinchZoom.options.minZoom = minZoom;pinchZoom.options.tapZoomFactor = minZoom;pinchZoom.options.xOffset = xOffset;pinchZoom.options.yOffset = yOffset;var event = {touches:[{pageX:pinchZoomImageWidth/2,pageY:clientHeight/2}]};setTimeout(function(){pinchZoom.handleDoubleTap(event);},300);}// 剪裁图像function clipImage(scale,x,y,callback){// 创建 canvasvar canvasId ="canvas_"+new Date().getTime()+""+parseInt(Math.random()*10000);$("<canvas></canvas>").hide().attr("id",canvasId).appendTo("body");var canvas=$("#"+canvasId)[0];var ctx=canvas.getContext("2d");// 释放canvasfunction releaseCanvas(){$("#"+canvasId).remove();}// canvas 宽度 高度canvas.width = pinchZoomImageWidth;canvas.height= pinchZoomImageHeight;if(p_w_picpath.width>p_w_picpath.height){y=y-yOffset;}else{x=x-xOffset;}ctx.drawImage(p_w_picpath,x/originScale,y/originScale,pinchZoomImageWidth/scale/originScale,pinchZoomImageHeight/scale/originScale,0,0,pinchZoomImageWidth,pinchZoomImageHeight);var dataURL = canvas.toDataURL();if(callback!=null){callback(dataURL);}releaseCanvas();}// 获取 pinch-zoom 缩放 偏移信息function retrievePositionInfo(transformCss){var infoStr = transformCss.replace("matrix(","");infoStr = infoStr.replace(")","");var arr = infoStr.split(",");var scale = arr[0];var x = arr[4];var y = arr[5];if(x<0){x = -1*x;}if(y<0){y=-1*y;}var result = {scale:scale,x:x/scale,y:y/scale};return result;}var PortraitClipUtil = {};PortraitClipUtil.loadImage=loadImage;window.PortraitClipUtil = PortraitClipUtil;
})(jQuery);

测试页面

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd">
<html>
<head><title>Pinchzoom.js Demo</title><meta charset="UTF-8" /><meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no"><meta name="apple-mobile-web-app-capable" content="yes" /><link rel="stylesheet" href="css/common/PortraitClip.css" /><style>body{margin:0;}</style>
</head>
<body style="height:900px;"><button id="upload-p_w_picpath">上传图片</button><p_w_picpath id="p_w_picpath" style="position: absolute;display:block;top:0;z-index:9999;"/><script type="text/javascript" src="dist/js/jquery-1.11.3.min.js"></script><script type="text/javascript" src="dist/js/pinchzoom-xiaomin.min.js"></script><script type="text/javascript" src="js/common/PortraitClip.js"></script><script>$("#upload-p_w_picpath").click(function(e){PortraitClipUtil.loadImage("frog.jpg",function(dataURL){$("#p_w_picpath").attr("src",dataURL);});});</script>
</body>
</html>

注:这边引入的是pinchzoom-xiaomin.min.js。对pinchzoom.min.js源代码有所变更。pinchzoom.js,pinchzoom.min.js,pinchzoom-xiaomin.js,pinchzoom-xiaomin.min.js在相应的附件中。