JavaScript按比例拖拉缩放_综合其它特效

JavaScript按比例拖拉缩放，很不错的代码，可以像PS一样拉出一个选择框，里面的很多方法都是我们值得学习的哦，好好研究一下吧。

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" mrc="text/html; charset=gb2312" />
<title>JavaScript拖拉缩放效果</title>
</head>
<body>
<script>

var isIE = (document.all) ? true : false;

var $ = function (id) {
	return "string" == typeof id ? document.getElementById(id) : id;
};

var Class = {
	create: function() {
		return function() { this.initialize.apply(this, arguments); }
	}
}

var Extend = function(destination, source) {
	for (var property in source) {
		destination[property] = source[property];
	}
}

var Bind = function(object, fun) {
	return function() {
		return fun.apply(object, arguments);
	}
}

var BindAsEventListener = function(object, fun) {
	var args = Array.prototype.slice.call(arguments).slice(2);
	return function(event) {
		return fun.apply(object, [event || window.event].concat(args));
	}
}

var CurrentStyle = function(element){
	return element.currentStyle || document.defaultView.getComputedStyle(element, null);
}

//缩放程序
var Resize = Class.create();
Resize.prototype = {
  //缩放对象
  initialize: function(obj, options) {
	this._obj = $(obj);//缩放对象
	
	this._styleWidth = this._styleHeight = this._styleLeft = this._styleTop = 0;//样式参数
	this._sideRight = this._sideDown = this._sideLeft = this._sideUp = 0;//坐标参数
	this._fixLeft = this._fixTop = 0;//定位参数
	this._scaleLeft = this._scaleTop = 0;//定位坐标
	
	this._mxSet = function(){};//范围设置程序
	this._mxRightWidth = this._mxDownHeight = this._mxUpHeight = this._mxLeftWidth = 0;//范围参数
	this._mxScaleWidth = this._mxScaleHeight = 0;//比例范围参数
	
	this._fun = function(){};//缩放执行程序
	
	//获取边框宽度
	var _style = CurrentStyle(this._obj);
	this._borderX = (parseInt(_style.borderLeftWidth) || 0) + (parseInt(_style.borderRightWidth) || 0);
	this._borderY = (parseInt(_style.borderTopWidth) || 0) + (parseInt(_style.borderBottomWidth) || 0);
	//事件对象(用于绑定移除事件)
	this._fR = BindAsEventListener(this, this.Resize);
	this._fS = Bind(this, this.Stop);
	
	this.SetOptions(options);
	//范围限制
	this.Max = !!this.options.Max;
	this._mxContainer = $(this.options.mxContainer) || null;
	this.mxLeft = Math.round(this.options.mxLeft);
	this.mxRight = Math.round(this.options.mxRight);
	this.mxTop = Math.round(this.options.mxTop);
	this.mxBottom = Math.round(this.options.mxBottom);
	//宽高限制
	this.Min = !!this.options.Min;
	this.minWidth = Math.round(this.options.minWidth);
	this.minHeight = Math.round(this.options.minHeight);
	//按比例缩放
	this.Scale = !!this.options.Scale;
	this.Ratio = Math.max(this.options.Ratio, 0);
	
	this.onResize = this.options.onResize;
	
	this._obj.style.position = "absolute";
	!this._mxContainer || CurrentStyle(this._mxContainer).position == "relative" || (this._mxContainer.style.position = "relative");
  },
  //设置默认属性
  SetOptions: function(options) {
    this.options = {//默认值
		Max:		false,//是否设置范围限制(为true时下面mx参数有用)
		mxContainer:"",//指定限制在容器内
		mxLeft:		0,//左边限制
		mxRight:	9999,//右边限制
		mxTop:		0,//上边限制
		mxBottom:	9999,//下边限制
		Min:		false,//是否最小宽高限制(为true时下面min参数有用)
		minWidth:	50,//最小宽度
		minHeight:	50,//最小高度
		Scale:		false,//是否按比例缩放
		Ratio:		0,//缩放比例(宽/高)
		onResize:	function(){}//缩放时执行
    };
    Extend(this.options, options || {});
  },
  //设置触发对象
  Set: function(resize, side) {
	var resize = $(resize), fun;
	if(!resize) return;
	//根据方向设置
	switch (side.toLowerCase()) {
	case "up" :
		fun = this.Up;
		break;
	case "down" :
		fun = this.Down;
		break;
	case "left" :
		fun = this.Left;
		break;
	case "right" :
		fun = this.Right;
		break;
	case "left-up" :
		fun = this.LeftUp;
		break;
	case "right-up" :
		fun = this.RightUp;
		break;
	case "left-down" :
		fun = this.LeftDown;
		break;
	case "right-down" :
	default :
		fun = this.RightDown;
	};
	//设置触发对象
	addEventHandler(resize, "mousedown", BindAsEventListener(this, this.Start, fun));
  },
  //准备缩放
  Start: function(e, fun, touch) {	
	//防止冒泡(跟拖放配合时设置)
	e.stopPropagation ? e.stopPropagation() : (e.cancelBubble = true);
	//设置执行程序
	this._fun = fun;
	//样式参数值
	this._styleWidth = this._obj.clientWidth;
	this._styleHeight = this._obj.clientHeight;
	this._styleLeft = this._obj.offsetLeft;
	this._styleTop = this._obj.offsetTop;
	//四条边定位坐标
	this._sideLeft = e.clientX - this._styleWidth;
	this._sideRight = e.clientX + this._styleWidth;
	this._sideUp = e.clientY - this._styleHeight;
	this._sideDown = e.clientY + this._styleHeight;
	//top和left定位参数
	this._fixLeft = this._styleLeft + this._styleWidth;
	this._fixTop = this._styleTop + this._styleHeight;
	//缩放比例
	if(this.Scale){
		//设置比例
		this.Ratio = Math.max(this.Ratio, 0) || this._styleWidth / this._styleHeight;
		//left和top的定位坐标
		this._scaleLeft = this._styleLeft + this._styleWidth / 2;
		this._scaleTop = this._styleTop + this._styleHeight / 2;
	};
	//范围限制
	if(this.Max){
		//设置范围参数
		var mxLeft = this.mxLeft, mxRight = this.mxRight, mxTop = this.mxTop, mxBottom = this.mxBottom;
		//如果设置了容器，再修正范围参数
		if(!!this._mxContainer){
			mxLeft = Math.max(mxLeft, 0);
			mxTop = Math.max(mxTop, 0);
			mxRight = Math.min(mxRight, this._mxContainer.clientWidth);
			mxBottom = Math.min(mxBottom, this._mxContainer.clientHeight);
		};
		//根据最小值再修正
		mxRight = Math.max(mxRight, mxLeft + (this.Min ? this.minWidth : 0) + this._borderX);
		mxBottom = Math.max(mxBottom, mxTop + (this.Min ? this.minHeight : 0) + this._borderY);
		//由于转向时要重新设置所以写成function形式
		this._mxSet = function(){
			this._mxRightWidth = mxRight - this._styleLeft - this._borderX;
			this._mxDownHeight = mxBottom - this._styleTop - this._borderY;
			this._mxUpHeight = Math.max(this._fixTop - mxTop, this.Min ? this.minHeight : 0);
			this._mxLeftWidth = Math.max(this._fixLeft - mxLeft, this.Min ? this.minWidth : 0);
		};
		this._mxSet();
		//有缩放比例下的范围限制
		if(this.Scale){
			this._mxScaleWidth = Math.min(this._scaleLeft - mxLeft, mxRight - this._scaleLeft - this._borderX) * 2;
			this._mxScaleHeight = Math.min(this._scaleTop - mxTop, mxBottom - this._scaleTop - this._borderY) * 2;
		};
	};
	//mousemove时缩放 mouseup时停止
	addEventHandler(document, "mousemove", this._fR);
	addEventHandler(document, "mouseup", this._fS);
	if(isIE){
		addEventHandler(this._obj, "losecapture", this._fS);
		this._obj.setCapture();
	}else{
		addEventHandler(window, "blur", this._fS);
		e.preventDefault();
	};
  },
  //缩放
  Resize: function(e) {
	//清除选择
	window.getSelection ? window.getSelection().removeAllRanges() : document.selection.empty();
	//执行缩放程序
	this._fun(e);
	//设置样式，变量必须大于等于0否则ie出错
	with(this._obj.style){
		width = this._styleWidth + "px"; height = this._styleHeight + "px";
		top = this._styleTop + "px"; left = this._styleLeft + "px";
	}
	//附加程序
	this.onResize();
  },
  //缩放程序
  //上
  Up: function(e) {
	this.RepairY(this._sideDown - e.clientY, this._mxUpHeight);
	this.RepairTop();
	this.TurnDown(this.Down);
  },
  //下
  Down: function(e) {
	this.RepairY(e.clientY - this._sideUp, this._mxDownHeight);
	this.TurnUp(this.Up);
  },
  //右
  Right: function(e) {
	this.RepairX(e.clientX - this._sideLeft, this._mxRightWidth);
	this.TurnLeft(this.Left);
  },
  //左
  Left: function(e) {
	this.RepairX(this._sideRight - e.clientX, this._mxLeftWidth);
	this.RepairLeft();
	this.TurnRight(this.Right);
  },
  //右下
  RightDown: function(e) {
	this.RepairAngle(
		e.clientX - this._sideLeft, this._mxRightWidth,
		e.clientY - this._sideUp, this._mxDownHeight
	);
	this.TurnLeft(this.LeftDown) || this.Scale || this.TurnUp(this.RightUp);
  },
  //右上
  RightUp: function(e) {
	this.RepairAngle(
		e.clientX - this._sideLeft, this._mxRightWidth,
		this._sideDown - e.clientY, this._mxUpHeight
	);
	this.RepairTop();
	this.TurnLeft(this.LeftUp) || this.Scale || this.TurnDown(this.RightDown);
  },
  //左下
  LeftDown: function(e) {
	this.RepairAngle(
		this._sideRight - e.clientX, this._mxLeftWidth,
		e.clientY - this._sideUp, this._mxDownHeight
	);
	this.RepairLeft();
	this.TurnRight(this.RightDown) || this.Scale || this.TurnUp(this.LeftUp);
  },
  //左上
  LeftUp: function(e) {
	this.RepairAngle(
		this._sideRight - e.clientX, this._mxLeftWidth,
		this._sideDown - e.clientY, this._mxUpHeight
	);
	this.RepairTop(); this.RepairLeft();
	this.TurnRight(this.RightUp) || this.Scale || this.TurnDown(this.LeftDown);
  },
  //修正程序
  //水平方向
  RepairX: function(iWidth, mxWidth) {
	iWidth = this.RepairWidth(iWidth, mxWidth);
	if(this.Scale){
		var iHeight = this.RepairScaleHeight(iWidth);
		if(this.Max && iHeight > this._mxScaleHeight){
			iHeight = this._mxScaleHeight;
			iWidth = this.RepairScaleWidth(iHeight);
		}else if(this.Min && iHeight < this.minHeight){
			var tWidth = this.RepairScaleWidth(this.minHeight);
			if(tWidth < mxWidth){ iHeight = this.minHeight; iWidth = tWidth; }
		}
		this._styleHeight = iHeight;
		this._styleTop = this._scaleTop - iHeight / 2;
	}
	this._styleWidth = iWidth;
  },
  //垂直方向
  RepairY: function(iHeight, mxHeight) {
	iHeight = this.RepairHeight(iHeight, mxHeight);
	if(this.Scale){
		var iWidth = this.RepairScaleWidth(iHeight);
		if(this.Max && iWidth > this._mxScaleWidth){
			iWidth = this._mxScaleWidth;
			iHeight = this.RepairScaleHeight(iWidth);
		}else if(this.Min && iWidth < this.minWidth){
			var tHeight = this.RepairScaleHeight(this.minWidth);
			if(tHeight < mxHeight){ iWidth = this.minWidth; iHeight = tHeight; }
		}
		this._styleWidth = iWidth;
		this._styleLeft = this._scaleLeft - iWidth / 2;
	}
	this._styleHeight = iHeight;
  },
  //对角方向
  RepairAngle: function(iWidth, mxWidth, iHeight, mxHeight) {
	iWidth = this.RepairWidth(iWidth, mxWidth);	
	if(this.Scale){
		iHeight = this.RepairScaleHeight(iWidth);
		if(this.Max && iHeight > mxHeight){
			iHeight = mxHeight;
			iWidth = this.RepairScaleWidth(iHeight);
		}else if(this.Min && iHeight < this.minHeight){
			var tWidth = this.RepairScaleWidth(this.minHeight);
			if(tWidth < mxWidth){ iHeight = this.minHeight; iWidth = tWidth; }
		}
	}else{
		iHeight = this.RepairHeight(iHeight, mxHeight);
	}
	this._styleWidth = iWidth;
	this._styleHeight = iHeight;
  },
  //top
  RepairTop: function() {
	this._styleTop = this._fixTop - this._styleHeight;
  },
  //left
  RepairLeft: function() {
	this._styleLeft = this._fixLeft - this._styleWidth;
  },
  //height
  RepairHeight: function(iHeight, mxHeight) {
	iHeight = Math.min(this.Max ? mxHeight : iHeight, iHeight);
	iHeight = Math.max(this.Min ? this.minHeight : iHeight, iHeight, 0);
	return iHeight;
  },
  //width
  RepairWidth: function(iWidth, mxWidth) {
	iWidth = Math.min(this.Max ? mxWidth : iWidth, iWidth);
	iWidth = Math.max(this.Min ? this.minWidth : iWidth, iWidth, 0);
	return iWidth;
  },
  //比例高度
  RepairScaleHeight: function(iWidth) {
	return Math.max(Math.round((iWidth + this._borderX) / this.Ratio - this._borderY), 0);
  },
  //比例宽度
  RepairScaleWidth: function(iHeight) {
	return Math.max(Math.round((iHeight + this._borderY) * this.Ratio - this._borderX), 0);
  },
  //转向程序
  //转右
  TurnRight: function(fun) {
	if(!(this.Min || this._styleWidth)){
		this._fun = fun;
		this._sideLeft = this._sideRight;
		this.Max && this._mxSet();
		return true;
	}
  },
  //转左
  TurnLeft: function(fun) {
	if(!(this.Min || this._styleWidth)){
		this._fun = fun;
		this._sideRight = this._sideLeft;
		this._fixLeft = this._styleLeft;
		this.Max && this._mxSet();
		return true;
	}
  },
  //转上
  TurnUp: function(fun) {
	if(!(this.Min || this._styleHeight)){
		this._fun = fun;
		this._sideDown = this._sideUp;
		this._fixTop = this._styleTop;
		this.Max && this._mxSet();
		return true;
	}
  },
  //转下
  TurnDown: function(fun) {
	if(!(this.Min || this._styleHeight)){
		this._fun = fun;
		this._sideUp = this._sideDown;
		this.Max && this._mxSet();
		return true;
	}
  },
  //停止缩放
  Stop: function() {
	removeEventHandler(document, "mousemove", this._fR);
	removeEventHandler(document, "mouseup", this._fS);
	if(isIE){
		removeEventHandler(this._obj, "losecapture", this._fS);
		this._obj.releaseCapture();
	}else{
		removeEventHandler(window, "blur", this._fS);
	}
  }
};

</script>
<script type="text/javascript" src="Drag.js"></script>

#rLeftDown,#rRightUp{cursor:ne-resize;}
#rRightDown,#rLeftUp{cursor:nw-resize;}
#rRight,#rLeft{cursor:e-resize;}
#rUp,#rDown{cursor:n-resize;}

#rLeftDown{left:-4px;bottom:-4px;}
#rRightUp{right:-4px;top:-4px;}
#rRightDown{right:-4px;bottom:-4px;background-color:#00F;}
#rLeftUp{left:-4px;top:-4px;}
#rRight{right:-4px;top:50%;margin-top:-4px;}
#rLeft{left:-4px;top:50%;margin-top:-4px;}
#rUp{top:-4px;left:50%;margin-left:-4px;}
#rDown{bottom:-4px;left:50%;margin-left:-4px;}

#bgDiv{width:600px; height:300px; border:10px solid #666666; position:relative;}
#dragDiv{border:1px solid #000000; width:100px; height:60px; top:50px; left:50px; background:#fff;}
</style>
<div id="bgDiv">
  <div id="dragDiv">
    <div id="rRightDown"> </div>
    <div id="rLeftDown"> </div>
    <div id="rRightUp"> </div>
    <div id="rLeftUp"> </div>
    <div id="rRight"> </div>
    <div id="rLeft"> </div>
    <div id="rUp"> </div>
    <div id="rDown"></div>
  </div>
</div>
<input id="idScale" type="button" value="设置比例" />
<input id="idMin" type="button" value="设置最小范围" />
<script>

var rs = new Resize("dragDiv", { Max: true, mxContainer: "bgDiv" });

rs.Set("rRightDown", "right-down");
rs.Set("rLeftDown", "left-down");

rs.Set("rRightUp", "right-up");
rs.Set("rLeftUp", "left-up");

rs.Set("rRight", "right");
rs.Set("rLeft", "left");

rs.Set("rUp", "up");
rs.Set("rDown", "down");

$("idScale").onclick = function(){
	if(rs.Scale){
		this.value = "设置比例";
		rs.Scale = false;
	}else{
		this.value = "取消比例";
		rs.Ratio = 0;
		rs.Scale = true;
	}
}

$("idMin").onclick = function(){
	if(rs.Min){
		this.value = "设置最小范围";
		rs.Min = false;
	}else{
		this.value = "取消最小范围";
		rs.Min = true;
	}
}

new Drag("dragDiv", { Limit: true, mxContainer: "bgDiv" });

</script>
</body>
</html>

所属频道：综合其它特效/更新时间：2013-06-03

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