JavaScript按比例拖拉缩放

2020-01-26 18:52:15

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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" content="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);}function addEventHandler(oTarget, sEventType, fnHandler) {	if (oTarget.addEventListener) {		oTarget.addEventListener(sEventType, fnHandler, false);	} else if (oTarget.attachEvent) {		oTarget.attachEvent("on" + sEventType, fnHandler);	} else {		oTarget["on" + sEventType] = fnHandler;	}};function removeEventHandler(oTarget, sEventType, fnHandler) {    if (oTarget.removeEventListener) {        oTarget.removeEventListener(sEventType, fnHandler, false);    } else if (oTarget.detachEvent) {        oTarget.detachEvent("on" + sEventType, fnHandler);    } else {         oTarget["on" + sEventType] = 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);  },  //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><style type="text/css">#rRightDown,#rLeftDown,#rLeftUp,#rRightUp,#rRight,#rLeft,#rUp,#rDown{	position:absolute;	background:#C00;	width:7px;	height:7px;	z-index:5;	font-size:0;}#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;	}}</script></body></html>

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