• 微信图片上添加昵称等信息拖动移动位置


    调用 

    var oImg = document.getElementById("cropPosterImg");
    fnImageCropRot(oImg);
    

      

    下载地址:http://www.zhangxinxu.com/study/down/jquery_jcrop_zh.zip

    crop_rotation/zxx.crop_rotation.js

    // zxx.crop_rotation.js by zhangxinxu  welcome to visit my personal website http://www.zhangxinxu.com/
    // 2010-05-06 v1.0 beta
    // 图片剪裁旋转前端展示
    /*一些说明:
    * 1. 旋转效果查看需通过在角度文本框中输入数值
    * 2. 后台处理图片需要5个参数,剪裁起始点,以及剪裁的高宽,这5个参数均可以通过id获取。其中角度值即旋转角度输入框的值,id为zxxRotAngle,坐标及高宽参数分别藏在4个隐藏的文本框中,id分别是:cropPosX, cropPosY, cropImageWidth, cropImageHeight
    * 3. 自动对比当前图片与原始图片尺寸比例,计算实际的剪裁值,对于高度及位置溢出也做了处理
    * 4. 如果出现由于图片旋转而发生遮挡的现象,设置遮挡元素的position属性为relative,z-index为1,可修复此问题
    * 5. 经我测试,excanvas.js需在头部加载以支持IE浏览器的canvas
    */
    var fnImageCropRot = function(o){
    	//o为图片对象
    	if(typeof(o) === "object" && o.nodeName.toLowerCase() === "img"){//检测是否是图片类型的DOM对象
    		//当前显示图片的高度和宽度
    		var iCurWidth = o.width, iCurHeight = o.height;
    		o.height = iCurHeight;
    		//获取实际图片的高宽
    		var oCreateImg = new Image();
    		oCreateImg.src = o.src;
    		var iOrigWidth = oCreateImg.width, iOrigHeight = oCreateImg.height;
    
    		if(iCurWidth && iOrigWidth){//如果宽度为不为0 - 意味着加载成功
    			//计算当前与实际的纵横比
    			var scaleX = iCurWidth / iOrigWidth;
    			var scaleY = iCurHeight / iOrigHeight;
    			//实现图片对象的包裹
    			//创建包裹div
    			var oRelDiv = document.createElement("div");
    			oRelDiv.style.position = "relative";
    			oRelDiv.style.width = iCurWidth + "px";
    			oRelDiv.style.height = iCurHeight + 30 + "px";
    			oRelDiv.style.top = "30px";
    			//定义ID方法
    			var ID = function(id){
    				return document.getElementById(id);
    			};
    			//插入到当前图片对象之前
    			o.parentNode.insertBefore(oRelDiv, o);
    			//初始化坐标与剪裁高宽
    			var cropW = ID("ncropImageWidth").value;
    			var cropH = ID("ncropImageHeight").value;
    			var posX = ID("ncropPosX").value;
    			var posY = ID("ncropPosY").value;
    			var qrimg = ID("ncropQrcodeimg").value;
    			var nameTextX = ID("label_name_x").value;
    			var nameTexty = ID("label_name_y").value;
    			var nameTextSize = ID("label_name_fsize").value;
    			var addressTextx = ID("label_address_x").value;
    			var addressTexty = ID("label_address_y").value;
    			var addressTextSize = ID("label_address_fsize").value;
    			var avatarImg = ID("avatarImg").value;
    			var avatarx = ID("label_avatar_x").value;
    			var avatary = ID("label_avatar_y").value;
    			//剪裁需要的HTML元素
    			var sInnerHtml = '<div style="font-size:12px; position:absolute; top:-24px; right:0;"><input id="zxxRotAngle" type="hidden" value="0" style="38px; height:15px; border:1px solid #a0b3d6; font-size:100%; padding:2px 0 1px 2px; margin-right:3px; color:#333333;" /><a scr="javascript:;" id="fnRefresh">刷新</a></div>'
    			+'<canvas id="zxxImageCanvas" style="position:absolute;"></canvas>'
    			+'<div id="zxxCropBox" style="height:'+cropH+'px; '+cropW+'px; position:absolute; left:'+posX+'px; top:'+posY+'px; border:1px solid black;">'
    				+'<div id="zxxDragBg" style="height:100%;background: #ebedf0 url('+qrimg+') no-repeat;background-size:100%; cursor:move;"></div>'
    				+'<div id="dragLeftTop" style="position:absolute; 4px; height:4px; border:1px solid #000; background:white; overflow:hidden; left:-3px; top:-3px; cursor:nw-resize;"></div>'
    				+'<div id="dragLeftBot" style="position:absolute; 4px; height:4px; border:1px solid #000; background:white; overflow:hidden; left:-3px; bottom:-3px; cursor:sw-resize;"></div>'
    				+'<div id="dragRightTop" style="position:absolute; 4px; height:4px; border:1px solid #000; background:white; overflow:hidden; right:-3px; top:-3px; cursor:ne-resize;"></div>'
    				+'<div id="dragRightBot" style="position:absolute; 4px; height:4px; border:1px solid #000; background:white; overflow:hidden; right:-3px; bottom:-3px; cursor:se-resize;"></div>'
    				+'<div id="dragTopCenter" style="position:absolute; 4px; height:4px; border:1px solid #000; background:white; overflow:hidden; top:-3px; left:50%; margin-left:-3px; cursor:n-resize;"></div>'
    				+'<div id="dragBotCenter" style="position:absolute; 4px; height:4px; border:1px solid #000; background:white; overflow:hidden; bottom:-3px; left:50%; margin-left:-3px; cursor:s-resize;"></div>'
    				+'<div id="dragRightCenter" style="position:absolute; 4px; height:4px; border:1px solid #000; background:white; overflow:hidden; right:-3px; top:50%; margin-top:-3px; cursor:e-resize;"></div>'
    				+'<div id="dragLeftCenter" style="position:absolute; 4px; height:4px; border:1px solid #000; background:white; overflow:hidden; left:-3px; top:50%; margin-top:-3px; cursor:w-resize;"></div>'
    			+'</div>'
    			+'<div id="labelName" style="position:absolute; left:'+nameTextX+'px; top:'+nameTexty+'px; font-size: '+nameTextSize+'px;font-family: simhei;"><div id="labelNameDrag" style="cursor:move;">昵称拖动试试</div></div>'
    			+'<span id="labelAddress" style="position:absolute; left:'+addressTextx+'px; top:'+addressTexty+'px; font-size: '+addressTextSize+'px;color: #666666;font-family: simhei;"><span id="labelAddressDrag" style="cursor:move;color:#999">江苏 徐州</span></span>'
    			+'<span id="labelAvatar" style="position:absolute; left:'+avatarx+'px; top:'+avatary+'px;"><img id="labelAvatarDrag" style="cursor:move;-moz-border-radius: 300px; -webkit-border-radius: 300px; 110px;" src="'+avatarImg+'"/></span>';
    			//嵌入HTML元素
    			oRelDiv.innerHTML = sInnerHtml;
    			//图片重新插入
    			var oCanvas = ID("zxxImageCanvas");
    			if(window.ActiveXObject){
    				//IE
    				oCanvas = window.G_vmlCanvasManager.initElement(oCanvas); //使IE支持动态创建的canvas元素
    			}
    			oRelDiv.insertBefore(o, oCanvas);
    			//---------------------------图片包裹装载完毕-----------------------
    
    			var fnCanvasRotate = function(canvas,img,rot){//canvas旋转角度的方法
    				//获取图片的高宽
    				var w = iCurWidth;
    				var h = iCurHeight;
    				//角度转为弧度
    				if(!rot){
    					rot = 0;	
    				}
    				var rotation = Math.PI * rot / 180;
    				var c = Math.round(Math.cos(rotation) * 1000) / 1000;
    				var s = Math.round(Math.sin(rotation) * 1000) / 1000;
    				//旋转后canvas标签的大小
    				canvas.height = Math.abs(c*h) + Math.abs(s*w);
    				canvas.width = Math.abs(c*w) + Math.abs(s*h);
    				//绘图开始
    				var context = canvas.getContext("2d");
    				context.save();
    				//改变中心点
    				if (rotation <= Math.PI/2) {
    					context.translate(s*h,0);
    				} else if (rotation <= Math.PI) {
    					context.translate(canvas.width,-c*h);
    				} else if (rotation <= 1.5*Math.PI) {
    					context.translate(-c*w,canvas.height);
    				} else {
    					context.translate(0,-s*w);
    				}
    				//旋转90°
    				context.rotate(rotation);
    				//绘制
    				context.drawImage(img, 0, 0, w, h);
    				context.restore();
    				img.style.display = "none";	
    			};
    			//侦听旋转角度输入框
    			ID("zxxRotAngle").onkeyup = function(){
    				var v = parseInt(this.value, 10);
    				if(!v){
    					v = 0;
    				}
    				//执行角度旋转
    				fnCanvasRotate(oCanvas, o, v);
    			};
    
    			//拖拽与拉伸方法
    			//拖拽拉伸所需参数
    			var params = {
    				left: 0,
    				top: 0,
    				0,
    				height:0,
    				currentX: 0,
    				currentY: 0,
    				flag: false,
    				kind: "drag",
    				activePoint: false
    			};
    
    			//获取相关CSS属性方法
    			var getCss = function(o,key){
    				return o.currentStyle? o.currentStyle[key] : document.defaultView.getComputedStyle(o,false)[key]; 	
    			};
    			var startDrag = function(point, target, kind){	
    				//point是拉伸点,target是被拉伸的目标,其高度及位置会发生改变
    				//此处的target与上面拖拽的target是同一目标,故其params.left,params.top可以共用,也必须共用
    				//初始化宽高
    				params.width = getCss(target, "width");
    				params.height = getCss(target, "height");
    				//初始化坐标
    				if(getCss(target, "left") !== "auto"){
    					params.left = getCss(target, "left");
    				}
    				if(getCss(target, "top") !== "auto"){
    					params.top = getCss(target, "top");
    				}
    				//target是移动对象
    				point.onmousedown = function(event){
    					params.kind = kind;
    					params.flag = true;
    					if(!event){
    						event = window.event;
    					}
    					var e = event;
    
    					//焦点放到当前拖拽的对象
    					params.activePoint = target;
    					params.left = getCss(target, "left");
    					params.top = getCss(target, "top");
    
    					params.currentX = e.clientX;
    					params.currentY = e.clientY;
    					//防止IE文字选中,有助于拖拽平滑
    					point.onselectstart = function(){
    						return false;
    					}
    				};
    				document.onmouseup = function(){
    					params.flag = false;
    					if(getCss(params.activePoint, "left") !== "auto"){
    						params.left = getCss(params.activePoint, "left");
    					}
    					if(getCss(params.activePoint, "top") !== "auto"){
    						params.top = getCss(params.activePoint, "top");
    					}
    
    					if(params.activePoint.id=="labelName"){
    						//给隐藏文本框赋值
    						posX = parseInt(params.activePoint.style.left);
    						posY = parseInt(params.activePoint.style.top);
    						ID("label_name_x").value = posX;
    						ID("label_name_y").value = posY;
    						return;
    					}else if(params.activePoint.id=="labelAddress"){
    						//给隐藏文本框赋值
    						posX = parseInt(params.activePoint.style.left);
    						posY = parseInt(params.activePoint.style.top);
    						ID("label_address_x").value = posX;
    						ID("label_address_y").value = posY;
    						return;
    					}else if(params.activePoint.id=="labelAvatar"){
    						//给隐藏文本框赋值
    						posX = parseInt(params.activePoint.style.left);
    						posY = parseInt(params.activePoint.style.top);
    						ID("label_avatar_x").value = posX;
    						ID("label_avatar_y").value = posY;
    						return;
    					}
    
    					params.width = getCss(params.activePoint, "width");
    					params.height = getCss(params.activePoint, "height");
    
    					//给隐藏文本框赋值
    					posX = parseInt(params.activePoint.style.left);
    					posY = parseInt(params.activePoint.style.top);
    					cropW = parseInt(params.activePoint.style.width);
    					cropH = parseInt(params.activePoint.style.height);
    					if(posX < 0){
    						posX = 0;	
    					}
    					if(posY < 0){
    						posY = 0;
    					}
    					if((posX + cropW) > iCurWidth){
    						cropW = iCurWidth - posX;	
    					}
    					if((posY + cropH) > iCurHeight){
    						cropH = iCurHeight - posY;	
    					}
    					//比例计算
    					posX = posX / scaleX;
    					posY /= scaleY;
    					cropW /= scaleX;
    					cropH /= scaleY;
    					//赋值
    					ID("ncropPosX").value = posX;
    					ID("ncropPosY").value = posY;
    					ID("ncropImageWidth").value = cropW;
    					ID("ncropImageHeight").value = cropH;
    				};
    				document.onmousemove = function(event){
    					var e = event ? event: window.event;
    					if(params.flag){
    						var nowX = e.clientX, nowY = e.clientY;
    						var disX = nowX - params.currentX, disY = nowY - params.currentY;
    						if(params.kind === "n"){
    							//上拉伸
    							//高度增加或减小,位置上下移动
    							target.style.height = parseInt(params.height) - disY + "px";
    							target.style.width = parseInt(params.width) - disY + "px";
    						}else if(params.kind === "w"){//左拉伸
    							target.style.left = parseInt(params.left) + disX + "px";
    							target.style.width = parseInt(params.width) - disX + "px";
    							target.style.height = parseInt(params.height) - disX + "px";
    						}else if(params.kind === "e"){//右拉伸
    							target.style.width = parseInt(params.width) + disX + "px";
    							target.style.height = parseInt(params.height) + disX + "px";
    						}else if(params.kind === "s"){//下拉伸
    							target.style.height = parseInt(params.height) + disY + "px";
    							target.style.width = parseInt(params.width) + disY + "px";
    						}else if(params.kind === "nw"){//左上拉伸
    							target.style.left = parseInt(params.left) + disX + "px";
    							target.style.width = parseInt(params.width) - disX + "px";
    							target.style.top = parseInt(params.top) + disX + "px";
    							target.style.height = parseInt(params.height) - disX + "px";
    						}else if(params.kind === "ne"){//右上拉伸
    							target.style.top = parseInt(params.top) + disY + "px";
    							target.style.height = parseInt(params.height) - disY + "px";
    							//右
    							target.style.width = parseInt(params.width) - disY + "px";
    						}else if(params.kind === "sw"){//左下拉伸
    							target.style.left = parseInt(params.left) + disX + "px";
    							target.style.width = parseInt(params.width) - disX + "px";
    							//下
    							target.style.height = parseInt(params.height) - disX + "px";
    						}else if(params.kind === "se"){//右下拉伸
    							target.style.width = parseInt(params.width) + disX + "px";
    							target.style.height = parseInt(params.height) + disX + "px";
    						}else{//移动
    							params.activePoint.style.left = parseInt(params.left) + disX + "px";
    							params.activePoint.style.top = parseInt(params.top) + disY + "px";
    						}
    					}
    				}
    			};
    
    			//绑定拖拽
    			startDrag(ID("zxxDragBg"),ID("zxxCropBox"),"drag");
    			startDrag(ID("labelNameDrag"),ID("labelName"),"drag");
    			startDrag(ID("labelAddressDrag"),ID("labelAddress"),"drag");
    			startDrag(ID("labelAvatarDrag"),ID("labelAvatar"),"drag");
    			//绑定拉伸
    			startDrag(ID("dragLeftTop"),ID("zxxCropBox"),"nw");
    			startDrag(ID("dragLeftBot"),ID("zxxCropBox"),"sw");
    			startDrag(ID("dragRightTop"),ID("zxxCropBox"),"ne");
    			startDrag(ID("dragRightBot"),ID("zxxCropBox"),"se");
    			startDrag(ID("dragTopCenter"),ID("zxxCropBox"),"n");
    			startDrag(ID("dragBotCenter"),ID("zxxCropBox"),"s");
    			startDrag(ID("dragRightCenter"),ID("zxxCropBox"),"e");
    			startDrag(ID("dragLeftCenter"),ID("zxxCropBox"),"w");
    
    			//图片不能被选中,目的在于使拖拽顺滑
    			ID("zxxImageCanvas").onselectstart = function(){
    				return false;
    			};
    			o.onselectstart = function(){
    				return false;
    			};
    		}//if end
    	}//if end
    };
    

      excanvas.js

    // Copyright 2006 Google Inc.
    //
    // Licensed under the Apache License, Version 2.0 (the "License");
    // you may not use this file except in compliance with the License.
    // You may obtain a copy of the License at
    //
    //   http://www.apache.org/licenses/LICENSE-2.0
    //
    // Unless required by applicable law or agreed to in writing, software
    // distributed under the License is distributed on an "AS IS" BASIS,
    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    // See the License for the specific language governing permissions and
    // limitations under the License.
    
    
    // Known Issues:
    //
    // * Patterns are not implemented.
    // * Radial gradient are not implemented. The VML version of these look very
    //   different from the canvas one.
    // * Clipping paths are not implemented.
    // * Coordsize. The width and height attribute have higher priority than the
    //   width and height style values which isn't correct.
    // * Painting mode isn't implemented.
    // * Canvas width/height should is using content-box by default. IE in
    //   Quirks mode will draw the canvas using border-box. Either change your
    //   doctype to HTML5
    //   (http://www.whatwg.org/specs/web-apps/current-work/#the-doctype)
    //   or use Box Sizing Behavior from WebFX
    //   (http://webfx.eae.net/dhtml/boxsizing/boxsizing.html)
    // * Non uniform scaling does not correctly scale strokes.
    // * Optimize. There is always room for speed improvements.
    
    // Only add this code if we do not already have a canvas implementation
    if (!document.createElement('canvas').getContext) {
    
    (function() {
    
      // alias some functions to make (compiled) code shorter
      var m = Math;
      var mr = m.round;
      var ms = m.sin;
      var mc = m.cos;
      var abs = m.abs;
      var sqrt = m.sqrt;
    
      // this is used for sub pixel precision
      var Z = 10;
      var Z2 = Z / 2;
    
      /**
       * This funtion is assigned to the <canvas> elements as element.getContext().
       * @this {HTMLElement}
       * @return {CanvasRenderingContext2D_}
       */
      function getContext() {
        return this.context_ ||
            (this.context_ = new CanvasRenderingContext2D_(this));
      }
    
      var slice = Array.prototype.slice;
    
      /**
       * Binds a function to an object. The returned function will always use the
       * passed in {@code obj} as {@code this}.
       *
       * Example:
       *
       *   g = bind(f, obj, a, b)
       *   g(c, d) // will do f.call(obj, a, b, c, d)
       *
       * @param {Function} f The function to bind the object to
       * @param {Object} obj The object that should act as this when the function
       *     is called
       * @param {*} var_args Rest arguments that will be used as the initial
       *     arguments when the function is called
       * @return {Function} A new function that has bound this
       */
      function bind(f, obj, var_args) {
        var a = slice.call(arguments, 2);
        return function() {
          return f.apply(obj, a.concat(slice.call(arguments)));
        };
      }
    
      var G_vmlCanvasManager_ = {
        init: function(opt_doc) {
          if (/MSIE/.test(navigator.userAgent) && !window.opera) {
            var doc = opt_doc || document;
            // Create a dummy element so that IE will allow canvas elements to be
            // recognized.
            doc.createElement('canvas');
            doc.attachEvent('onreadystatechange', bind(this.init_, this, doc));
          }
        },
    
        init_: function(doc) {
          // create xmlns
          if (!doc.namespaces['g_vml_']) {
            doc.namespaces.add('g_vml_', 'urn:schemas-microsoft-com:vml',
                               '#default#VML');
    
          }
          if (!doc.namespaces['g_o_']) {
            doc.namespaces.add('g_o_', 'urn:schemas-microsoft-com:office:office',
                               '#default#VML');
          }
    
          // Setup default CSS.  Only add one style sheet per document
          if (!doc.styleSheets['ex_canvas_']) {
            var ss = doc.createStyleSheet();
            ss.owningElement.id = 'ex_canvas_';
            ss.cssText = 'canvas{display:inline-block;overflow:hidden;' +
                // default size is 300x150 in Gecko and Opera
                'text-align:left;300px;height:150px}' +
                'g_vml_\\:*{behavior:url(#default#VML)}' +
                'g_o_\\:*{behavior:url(#default#VML)}';
    
          }
    
          // find all canvas elements
          var els = doc.getElementsByTagName('canvas');
          for (var i = 0; i < els.length; i++) {
            this.initElement(els[i]);
          }
        },
    
        /**
         * Public initializes a canvas element so that it can be used as canvas
         * element from now on. This is called automatically before the page is
         * loaded but if you are creating elements using createElement you need to
         * make sure this is called on the element.
         * @param {HTMLElement} el The canvas element to initialize.
         * @return {HTMLElement} the element that was created.
         */
        initElement: function(el) {
          if (!el.getContext) {
    
            el.getContext = getContext;
    
            // Remove fallback content. There is no way to hide text nodes so we
            // just remove all childNodes. We could hide all elements and remove
            // text nodes but who really cares about the fallback content.
            el.innerHTML = '';
    
            // do not use inline function because that will leak memory
            el.attachEvent('onpropertychange', onPropertyChange);
            el.attachEvent('onresize', onResize);
    
            var attrs = el.attributes;
            if (attrs.width && attrs.width.specified) {
              // TODO: use runtimeStyle and coordsize
              // el.getContext().setWidth_(attrs.width.nodeValue);
              el.style.width = attrs.width.nodeValue + 'px';
            } else {
              el.width = el.clientWidth;
            }
            if (attrs.height && attrs.height.specified) {
              // TODO: use runtimeStyle and coordsize
              // el.getContext().setHeight_(attrs.height.nodeValue);
              el.style.height = attrs.height.nodeValue + 'px';
            } else {
              el.height = el.clientHeight;
            }
            //el.getContext().setCoordsize_()
          }
          return el;
        }
      };
    
      function onPropertyChange(e) {
        var el = e.srcElement;
    
        switch (e.propertyName) {
          case 'width':
            el.style.width = el.attributes.width.nodeValue + 'px';
            el.getContext().clearRect();
            break;
          case 'height':
            el.style.height = el.attributes.height.nodeValue + 'px';
            el.getContext().clearRect();
            break;
        }
      }
    
      function onResize(e) {
        var el = e.srcElement;
        if (el.firstChild) {
          el.firstChild.style.width =  el.clientWidth + 'px';
          el.firstChild.style.height = el.clientHeight + 'px';
        }
      }
    
      G_vmlCanvasManager_.init();
    
      // precompute "00" to "FF"
      var dec2hex = [];
      for (var i = 0; i < 16; i++) {
        for (var j = 0; j < 16; j++) {
          dec2hex[i * 16 + j] = i.toString(16) + j.toString(16);
        }
      }
    
      function createMatrixIdentity() {
        return [
          [1, 0, 0],
          [0, 1, 0],
          [0, 0, 1]
        ];
      }
    
      function matrixMultiply(m1, m2) {
        var result = createMatrixIdentity();
    
        for (var x = 0; x < 3; x++) {
          for (var y = 0; y < 3; y++) {
            var sum = 0;
    
            for (var z = 0; z < 3; z++) {
              sum += m1[x][z] * m2[z][y];
            }
    
            result[x][y] = sum;
          }
        }
        return result;
      }
    
      function copyState(o1, o2) {
        o2.fillStyle     = o1.fillStyle;
        o2.lineCap       = o1.lineCap;
        o2.lineJoin      = o1.lineJoin;
        o2.lineWidth     = o1.lineWidth;
        o2.miterLimit    = o1.miterLimit;
        o2.shadowBlur    = o1.shadowBlur;
        o2.shadowColor   = o1.shadowColor;
        o2.shadowOffsetX = o1.shadowOffsetX;
        o2.shadowOffsetY = o1.shadowOffsetY;
        o2.strokeStyle   = o1.strokeStyle;
        o2.globalAlpha   = o1.globalAlpha;
        o2.arcScaleX_    = o1.arcScaleX_;
        o2.arcScaleY_    = o1.arcScaleY_;
        o2.lineScale_    = o1.lineScale_;
      }
    
      function processStyle(styleString) {
        var str, alpha = 1;
    
        styleString = String(styleString);
        if (styleString.substring(0, 3) == 'rgb') {
          var start = styleString.indexOf('(', 3);
          var end = styleString.indexOf(')', start + 1);
          var guts = styleString.substring(start + 1, end).split(',');
    
          str = '#';
          for (var i = 0; i < 3; i++) {
            str += dec2hex[Number(guts[i])];
          }
    
          if (guts.length == 4 && styleString.substr(3, 1) == 'a') {
            alpha = guts[3];
          }
        } else {
          str = styleString;
        }
    
        return {color: str, alpha: alpha};
      }
    
      function processLineCap(lineCap) {
        switch (lineCap) {
          case 'butt':
            return 'flat';
          case 'round':
            return 'round';
          case 'square':
          default:
            return 'square';
        }
      }
    
      /**
       * This class implements CanvasRenderingContext2D interface as described by
       * the WHATWG.
       * @param {HTMLElement} surfaceElement The element that the 2D context should
       * be associated with
       */
      function CanvasRenderingContext2D_(surfaceElement) {
        this.m_ = createMatrixIdentity();
    
        this.mStack_ = [];
        this.aStack_ = [];
        this.currentPath_ = [];
    
        // Canvas context properties
        this.strokeStyle = '#000';
        this.fillStyle = '#000';
    
        this.lineWidth = 1;
        this.lineJoin = 'miter';
        this.lineCap = 'butt';
        this.miterLimit = Z * 1;
        this.globalAlpha = 1;
        this.canvas = surfaceElement;
    
        var el = surfaceElement.ownerDocument.createElement('div');
        el.style.width =  surfaceElement.clientWidth + 'px';
        el.style.height = surfaceElement.clientHeight + 'px';
        el.style.overflow = 'hidden';
        el.style.position = 'absolute';
        surfaceElement.appendChild(el);
    
        this.element_ = el;
        this.arcScaleX_ = 1;
        this.arcScaleY_ = 1;
        this.lineScale_ = 1;
      }
    
      var contextPrototype = CanvasRenderingContext2D_.prototype;
      contextPrototype.clearRect = function() {
        this.element_.innerHTML = '';
      };
    
      contextPrototype.beginPath = function() {
        // TODO: Branch current matrix so that save/restore has no effect
        //       as per safari docs.
        this.currentPath_ = [];
      };
    
      contextPrototype.moveTo = function(aX, aY) {
        var p = this.getCoords_(aX, aY);
        this.currentPath_.push({type: 'moveTo', x: p.x, y: p.y});
        this.currentX_ = p.x;
        this.currentY_ = p.y;
      };
    
      contextPrototype.lineTo = function(aX, aY) {
        var p = this.getCoords_(aX, aY);
        this.currentPath_.push({type: 'lineTo', x: p.x, y: p.y});
    
        this.currentX_ = p.x;
        this.currentY_ = p.y;
      };
    
      contextPrototype.bezierCurveTo = function(aCP1x, aCP1y,
                                                aCP2x, aCP2y,
                                                aX, aY) {
        var p = this.getCoords_(aX, aY);
        var cp1 = this.getCoords_(aCP1x, aCP1y);
        var cp2 = this.getCoords_(aCP2x, aCP2y);
        bezierCurveTo(this, cp1, cp2, p);
      };
    
      // Helper function that takes the already fixed cordinates.
      function bezierCurveTo(self, cp1, cp2, p) {
        self.currentPath_.push({
          type: 'bezierCurveTo',
          cp1x: cp1.x,
          cp1y: cp1.y,
          cp2x: cp2.x,
          cp2y: cp2.y,
          x: p.x,
          y: p.y
        });
        self.currentX_ = p.x;
        self.currentY_ = p.y;
      }
    
      contextPrototype.quadraticCurveTo = function(aCPx, aCPy, aX, aY) {
        // the following is lifted almost directly from
        // http://developer.mozilla.org/en/docs/Canvas_tutorial:Drawing_shapes
    
        var cp = this.getCoords_(aCPx, aCPy);
        var p = this.getCoords_(aX, aY);
    
        var cp1 = {
          x: this.currentX_ + 2.0 / 3.0 * (cp.x - this.currentX_),
          y: this.currentY_ + 2.0 / 3.0 * (cp.y - this.currentY_)
        };
        var cp2 = {
          x: cp1.x + (p.x - this.currentX_) / 3.0,
          y: cp1.y + (p.y - this.currentY_) / 3.0
        };
    
        bezierCurveTo(this, cp1, cp2, p);
      };
    
      contextPrototype.arc = function(aX, aY, aRadius,
                                      aStartAngle, aEndAngle, aClockwise) {
        aRadius *= Z;
        var arcType = aClockwise ? 'at' : 'wa';
    
        var xStart = aX + mc(aStartAngle) * aRadius - Z2;
        var yStart = aY + ms(aStartAngle) * aRadius - Z2;
    
        var xEnd = aX + mc(aEndAngle) * aRadius - Z2;
        var yEnd = aY + ms(aEndAngle) * aRadius - Z2;
    
        // IE won't render arches drawn counter clockwise if xStart == xEnd.
        if (xStart == xEnd && !aClockwise) {
          xStart += 0.125; // Offset xStart by 1/80 of a pixel. Use something
                           // that can be represented in binary
        }
    
        var p = this.getCoords_(aX, aY);
        var pStart = this.getCoords_(xStart, yStart);
        var pEnd = this.getCoords_(xEnd, yEnd);
    
        this.currentPath_.push({type: arcType,
                               x: p.x,
                               y: p.y,
                               radius: aRadius,
                               xStart: pStart.x,
                               yStart: pStart.y,
                               xEnd: pEnd.x,
                               yEnd: pEnd.y});
    
      };
    
      contextPrototype.rect = function(aX, aY, aWidth, aHeight) {
        this.moveTo(aX, aY);
        this.lineTo(aX + aWidth, aY);
        this.lineTo(aX + aWidth, aY + aHeight);
        this.lineTo(aX, aY + aHeight);
        this.closePath();
      };
    
      contextPrototype.strokeRect = function(aX, aY, aWidth, aHeight) {
        var oldPath = this.currentPath_;
        this.beginPath();
    
        this.moveTo(aX, aY);
        this.lineTo(aX + aWidth, aY);
        this.lineTo(aX + aWidth, aY + aHeight);
        this.lineTo(aX, aY + aHeight);
        this.closePath();
        this.stroke();
    
        this.currentPath_ = oldPath;
      };
    
      contextPrototype.fillRect = function(aX, aY, aWidth, aHeight) {
        var oldPath = this.currentPath_;
        this.beginPath();
    
        this.moveTo(aX, aY);
        this.lineTo(aX + aWidth, aY);
        this.lineTo(aX + aWidth, aY + aHeight);
        this.lineTo(aX, aY + aHeight);
        this.closePath();
        this.fill();
    
        this.currentPath_ = oldPath;
      };
    
      contextPrototype.createLinearGradient = function(aX0, aY0, aX1, aY1) {
        var gradient = new CanvasGradient_('gradient');
        gradient.x0_ = aX0;
        gradient.y0_ = aY0;
        gradient.x1_ = aX1;
        gradient.y1_ = aY1;
        return gradient;
      };
    
      contextPrototype.createRadialGradient = function(aX0, aY0, aR0,
                                                       aX1, aY1, aR1) {
        var gradient = new CanvasGradient_('gradientradial');
        gradient.x0_ = aX0;
        gradient.y0_ = aY0;
        gradient.r0_ = aR0;
        gradient.x1_ = aX1;
        gradient.y1_ = aY1;
        gradient.r1_ = aR1;
        return gradient;
      };
    
      contextPrototype.drawImage = function(image, var_args) {
        var dx, dy, dw, dh, sx, sy, sw, sh;
    
        // to find the original width we overide the width and height
        var oldRuntimeWidth = image.runtimeStyle.width;
        var oldRuntimeHeight = image.runtimeStyle.height;
        image.runtimeStyle.width = 'auto';
        image.runtimeStyle.height = 'auto';
    
        // get the original size
        var w = image.width;
        var h = image.height;
    
        // and remove overides
        image.runtimeStyle.width = oldRuntimeWidth;
        image.runtimeStyle.height = oldRuntimeHeight;
    
        if (arguments.length == 3) {
          dx = arguments[1];
          dy = arguments[2];
          sx = sy = 0;
          sw = dw = w;
          sh = dh = h;
        } else if (arguments.length == 5) {
          dx = arguments[1];
          dy = arguments[2];
          dw = arguments[3];
          dh = arguments[4];
          sx = sy = 0;
          sw = w;
          sh = h;
        } else if (arguments.length == 9) {
          sx = arguments[1];
          sy = arguments[2];
          sw = arguments[3];
          sh = arguments[4];
          dx = arguments[5];
          dy = arguments[6];
          dw = arguments[7];
          dh = arguments[8];
        } else {
          throw Error('Invalid number of arguments');
        }
    
        var d = this.getCoords_(dx, dy);
    
        var w2 = sw / 2;
        var h2 = sh / 2;
    
        var vmlStr = [];
    
        var W = 10;
        var H = 10;
    
        // For some reason that I've now forgotten, using divs didn't work
        vmlStr.push(' <g_vml_:group',
                    ' coordsize="', Z * W, ',', Z * H, '"',
                    ' coordorigin="0,0"' ,
                    ' style="', W, 'px;height:', H, 'px;position:absolute;');
    
        // If filters are necessary (rotation exists), create them
        // filters are bog-slow, so only create them if abbsolutely necessary
        // The following check doesn't account for skews (which don't exist
        // in the canvas spec (yet) anyway.
    
        if (this.m_[0][0] != 1 || this.m_[0][1]) {
          var filter = [];
    
          // Note the 12/21 reversal
          filter.push('M11=', this.m_[0][0], ',',
                      'M12=', this.m_[1][0], ',',
                      'M21=', this.m_[0][1], ',',
                      'M22=', this.m_[1][1], ',',
                      'Dx=', mr(d.x / Z), ',',
                      'Dy=', mr(d.y / Z), '');
    
          // Bounding box calculation (need to minimize displayed area so that
          // filters don't waste time on unused pixels.
          var max = d;
          var c2 = this.getCoords_(dx + dw, dy);
          var c3 = this.getCoords_(dx, dy + dh);
          var c4 = this.getCoords_(dx + dw, dy + dh);
    
          max.x = m.max(max.x, c2.x, c3.x, c4.x);
          max.y = m.max(max.y, c2.y, c3.y, c4.y);
    
          vmlStr.push('padding:0 ', mr(max.x / Z), 'px ', mr(max.y / Z),
                      'px 0;filter:progid:DXImageTransform.Microsoft.Matrix(',
                      filter.join(''), ", sizingmethod='clip');")
        } else {
          vmlStr.push('top:', mr(d.y / Z), 'px;left:', mr(d.x / Z), 'px;');
        }
    
        vmlStr.push(' ">' ,
                    '<g_vml_:image src="', image.src, '"',
                    ' style="', Z * dw, 'px;',
                    ' height:', Z * dh, 'px;"',
                    ' cropleft="', sx / w, '"',
                    ' croptop="', sy / h, '"',
                    ' cropright="', (w - sx - sw) / w, '"',
                    ' cropbottom="', (h - sy - sh) / h, '"',
                    ' />',
                    '</g_vml_:group>');
    
        this.element_.insertAdjacentHTML('BeforeEnd',
                                        vmlStr.join(''));
      };
    
      contextPrototype.stroke = function(aFill) {
        var lineStr = [];
        var lineOpen = false;
        var a = processStyle(aFill ? this.fillStyle : this.strokeStyle);
        var color = a.color;
        var opacity = a.alpha * this.globalAlpha;
    
        var W = 10;
        var H = 10;
    
        lineStr.push('<g_vml_:shape',
                     ' filled="', !!aFill, '"',
                     ' style="position:absolute;', W, 'px;height:', H, 'px;"',
                     ' coordorigin="0 0" coordsize="', Z * W, ' ', Z * H, '"',
                     ' stroked="', !aFill, '"',
                     ' path="');
    
        var newSeq = false;
        var min = {x: null, y: null};
        var max = {x: null, y: null};
    
        for (var i = 0; i < this.currentPath_.length; i++) {
          var p = this.currentPath_[i];
          var c;
    
          switch (p.type) {
            case 'moveTo':
              c = p;
              lineStr.push(' m ', mr(p.x), ',', mr(p.y));
              break;
            case 'lineTo':
              lineStr.push(' l ', mr(p.x), ',', mr(p.y));
              break;
            case 'close':
              lineStr.push(' x ');
              p = null;
              break;
            case 'bezierCurveTo':
              lineStr.push(' c ',
                           mr(p.cp1x), ',', mr(p.cp1y), ',',
                           mr(p.cp2x), ',', mr(p.cp2y), ',',
                           mr(p.x), ',', mr(p.y));
              break;
            case 'at':
            case 'wa':
              lineStr.push(' ', p.type, ' ',
                           mr(p.x - this.arcScaleX_ * p.radius), ',',
                           mr(p.y - this.arcScaleY_ * p.radius), ' ',
                           mr(p.x + this.arcScaleX_ * p.radius), ',',
                           mr(p.y + this.arcScaleY_ * p.radius), ' ',
                           mr(p.xStart), ',', mr(p.yStart), ' ',
                           mr(p.xEnd), ',', mr(p.yEnd));
              break;
          }
    
    
          // TODO: Following is broken for curves due to
          //       move to proper paths.
    
          // Figure out dimensions so we can do gradient fills
          // properly
          if (p) {
            if (min.x == null || p.x < min.x) {
              min.x = p.x;
            }
            if (max.x == null || p.x > max.x) {
              max.x = p.x;
            }
            if (min.y == null || p.y < min.y) {
              min.y = p.y;
            }
            if (max.y == null || p.y > max.y) {
              max.y = p.y;
            }
          }
        }
        lineStr.push(' ">');
    
        if (!aFill) {
          var lineWidth = this.lineScale_ * this.lineWidth;
    
          // VML cannot correctly render a line if the width is less than 1px.
          // In that case, we dilute the color to make the line look thinner.
          if (lineWidth < 1) {
            opacity *= lineWidth;
          }
    
          lineStr.push(
            '<g_vml_:stroke',
            ' opacity="', opacity, '"',
            ' joinstyle="', this.lineJoin, '"',
            ' miterlimit="', this.miterLimit, '"',
            ' endcap="', processLineCap(this.lineCap), '"',
            ' weight="', lineWidth, 'px"',
            ' color="', color, '" />'
          );
        } else if (typeof this.fillStyle == 'object') {
          var fillStyle = this.fillStyle;
          var angle = 0;
          var focus = {x: 0, y: 0};
    
          // additional offset
          var shift = 0;
          // scale factor for offset
          var expansion = 1;
    
          if (fillStyle.type_ == 'gradient') {
            var x0 = fillStyle.x0_ / this.arcScaleX_;
            var y0 = fillStyle.y0_ / this.arcScaleY_;
            var x1 = fillStyle.x1_ / this.arcScaleX_;
            var y1 = fillStyle.y1_ / this.arcScaleY_;
            var p0 = this.getCoords_(x0, y0);
            var p1 = this.getCoords_(x1, y1);
            var dx = p1.x - p0.x;
            var dy = p1.y - p0.y;
            angle = Math.atan2(dx, dy) * 180 / Math.PI;
    
            // The angle should be a non-negative number.
            if (angle < 0) {
              angle += 360;
            }
    
            // Very small angles produce an unexpected result because they are
            // converted to a scientific notation string.
            if (angle < 1e-6) {
              angle = 0;
            }
          } else {
            var p0 = this.getCoords_(fillStyle.x0_, fillStyle.y0_);
            var width  = max.x - min.x;
            var height = max.y - min.y;
            focus = {
              x: (p0.x - min.x) / width,
              y: (p0.y - min.y) / height
            };
    
            width  /= this.arcScaleX_ * Z;
            height /= this.arcScaleY_ * Z;
            var dimension = m.max(width, height);
            shift = 2 * fillStyle.r0_ / dimension;
            expansion = 2 * fillStyle.r1_ / dimension - shift;
          }
    
          // We need to sort the color stops in ascending order by offset,
          // otherwise IE won't interpret it correctly.
          var stops = fillStyle.colors_;
          stops.sort(function(cs1, cs2) {
            return cs1.offset - cs2.offset;
          });
    
          var length = stops.length;
          var color1 = stops[0].color;
          var color2 = stops[length - 1].color;
          var opacity1 = stops[0].alpha * this.globalAlpha;
          var opacity2 = stops[length - 1].alpha * this.globalAlpha;
    
          var colors = [];
          for (var i = 0; i < length; i++) {
            var stop = stops[i];
            colors.push(stop.offset * expansion + shift + ' ' + stop.color);
          }
    
          // When colors attribute is used, the meanings of opacity and o:opacity2
          // are reversed.
          lineStr.push('<g_vml_:fill type="', fillStyle.type_, '"',
                       ' method="none" focus="100%"',
                       ' color="', color1, '"',
                       ' color2="', color2, '"',
                       ' colors="', colors.join(','), '"',
                       ' opacity="', opacity2, '"',
                       ' g_o_:opacity2="', opacity1, '"',
                       ' angle="', angle, '"',
                       ' focusposition="', focus.x, ',', focus.y, '" />');
        } else {
          lineStr.push('<g_vml_:fill color="', color, '" opacity="', opacity,
                       '" />');
        }
    
        lineStr.push('</g_vml_:shape>');
    
        this.element_.insertAdjacentHTML('beforeEnd', lineStr.join(''));
      };
    
      contextPrototype.fill = function() {
        this.stroke(true);
      }
    
      contextPrototype.closePath = function() {
        this.currentPath_.push({type: 'close'});
      };
    
      /**
       * @private
       */
      contextPrototype.getCoords_ = function(aX, aY) {
        var m = this.m_;
        return {
          x: Z * (aX * m[0][0] + aY * m[1][0] + m[2][0]) - Z2,
          y: Z * (aX * m[0][1] + aY * m[1][1] + m[2][1]) - Z2
        }
      };
    
      contextPrototype.save = function() {
        var o = {};
        copyState(this, o);
        this.aStack_.push(o);
        this.mStack_.push(this.m_);
        this.m_ = matrixMultiply(createMatrixIdentity(), this.m_);
      };
    
      contextPrototype.restore = function() {
        copyState(this.aStack_.pop(), this);
        this.m_ = this.mStack_.pop();
      };
    
      function matrixIsFinite(m) {
        for (var j = 0; j < 3; j++) {
          for (var k = 0; k < 2; k++) {
            if (!isFinite(m[j][k]) || isNaN(m[j][k])) {
              return false;
            }
          }
        }
        return true;
      }
    
      function setM(ctx, m, updateLineScale) {
        if (!matrixIsFinite(m)) {
          return;
        }
        ctx.m_ = m;
    
        if (updateLineScale) {
          // Get the line scale.
          // Determinant of this.m_ means how much the area is enlarged by the
          // transformation. So its square root can be used as a scale factor
          // for width.
          var det = m[0][0] * m[1][1] - m[0][1] * m[1][0];
          ctx.lineScale_ = sqrt(abs(det));
        }
      }
    
      contextPrototype.translate = function(aX, aY) {
        var m1 = [
          [1,  0,  0],
          [0,  1,  0],
          [aX, aY, 1]
        ];
    
        setM(this, matrixMultiply(m1, this.m_), false);
      };
    
      contextPrototype.rotate = function(aRot) {
        var c = mc(aRot);
        var s = ms(aRot);
    
        var m1 = [
          [c,  s, 0],
          [-s, c, 0],
          [0,  0, 1]
        ];
    
        setM(this, matrixMultiply(m1, this.m_), false);
      };
    
      contextPrototype.scale = function(aX, aY) {
        this.arcScaleX_ *= aX;
        this.arcScaleY_ *= aY;
        var m1 = [
          [aX, 0,  0],
          [0,  aY, 0],
          [0,  0,  1]
        ];
    
        setM(this, matrixMultiply(m1, this.m_), true);
      };
    
      contextPrototype.transform = function(m11, m12, m21, m22, dx, dy) {
        var m1 = [
          [m11, m12, 0],
          [m21, m22, 0],
          [dx,  dy,  1]
        ];
    
        setM(this, matrixMultiply(m1, this.m_), true);
      };
    
      contextPrototype.setTransform = function(m11, m12, m21, m22, dx, dy) {
        var m = [
          [m11, m12, 0],
          [m21, m22, 0],
          [dx,  dy,  1]
        ];
    
        setM(this, m, true);
      };
    
      /******** STUBS ********/
      contextPrototype.clip = function() {
        // TODO: Implement
      };
    
      contextPrototype.arcTo = function() {
        // TODO: Implement
      };
    
      contextPrototype.createPattern = function() {
        return new CanvasPattern_;
      };
    
      // Gradient / Pattern Stubs
      function CanvasGradient_(aType) {
        this.type_ = aType;
        this.x0_ = 0;
        this.y0_ = 0;
        this.r0_ = 0;
        this.x1_ = 0;
        this.y1_ = 0;
        this.r1_ = 0;
        this.colors_ = [];
      }
    
      CanvasGradient_.prototype.addColorStop = function(aOffset, aColor) {
        aColor = processStyle(aColor);
        this.colors_.push({offset: aOffset,
                           color: aColor.color,
                           alpha: aColor.alpha});
      };
    
      function CanvasPattern_() {}
    
      // set up externs
      G_vmlCanvasManager = G_vmlCanvasManager_;
      CanvasRenderingContext2D = CanvasRenderingContext2D_;
      CanvasGradient = CanvasGradient_;
      CanvasPattern = CanvasPattern_;
    
    })();
    
    } // if
    

      

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  • 原文地址:https://www.cnblogs.com/verylove/p/5302891.html
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