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="width: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; width:‘+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; width: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; width: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; width: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; width: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; width: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; width: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; width: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; width: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;width: 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,
				width: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;width: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="width:‘, 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="width:‘, 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;width:‘, 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

  

微信图片上添加昵称等信息拖动移动位置

上一篇:微信小程序前端promise封装


下一篇:[编程题]微信红包