首页
所有分类
TAGS
文字工具 EMOJI BIBLE
编程 Javascript

JavaScript实现选择框按比例拖拉缩放的方法

Posted in Javascript onAugust 04, 2015

本文实例讲述了JavaScript实现选择框按比例拖拉缩放的方法。分享给大家供大家参考。具体如下：

这里通过javascript实现可以像PS一样拉出一个选择框的效果。里面的很多方法都是我们值得学习的。

运行效果如下图所示：

JavaScript实现选择框按比例拖拉缩放的方法

具体代码如下：

<!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>

希望本文所述对大家的javascript程序设计有所帮助。

JavaScript实现选择框按比例拖拉缩放的方法

- Author -

皮蛋

声明：登载此文出于传递更多信息之目的，并不意味着赞同其观点或证实其描述。

Javascript 相关文章推荐
ExtJS 2.0 GridPanel基本表格简明教程
May 25 Javascript
SWFObject 2.1以上版本语法介绍
Jul 10 Javascript
一个JavaScript函数把URL参数解析成Json对象
Sep 24 Javascript
node.js中的require使用详解
Dec 15 Javascript
JQuery自动触发事件的方法
Jun 13 Javascript
JS基于面向对象实现的多个倒计时器功能示例
Feb 28 Javascript
如何将 jQuery 从你的 Bootstrap 项目中移除(取而代之使用Vue.js)
Jul 17 jQuery
js HTML5 canvas绘制图片的方法
Sep 08 Javascript
基于Bootstrap下拉框插件bootstrap-select使用方法详解
Aug 07 Javascript
小试SVG之新手小白入门教程
Jan 08 Javascript
js中数组常用方法总结（推荐）
Apr 09 Javascript
详解Vue3.0 前的 TypeScript 最佳入门实践
Jun 18 Javascript
Javascript实现可旋转的圆圈实例代码
Aug 04 #Javascript
JavaScript数组各种常见用法实例分析
Aug 04 #Javascript
基于Jquery实现表单验证
Jul 20 #Javascript
javascript+HTML5的canvas实现七夕情人节3D玫瑰花效果代码
Aug 04 #Javascript
jq实现左侧显示图片右侧文字滑动切换效果
Aug 04 #Javascript
javascript控制图片播放的实现代码
Jul 29 #Javascript
两种JS实现屏蔽鼠标右键的方法
Aug 20 #Javascript
ipv6(1) 事务(5) 策略(1) 逻辑架构(1) 锁(1) 弱口令(1) 缓存(3) offset(1) 性能优化(3) 内存(1)
You might like
iOS+PHP注册登录系统 PHP部分（上）
2016/12/26 PHP
js 获取浏览器高度和宽度值(多浏览器)
2009/09/02 Javascript
Javasipt:操作radio标签详解
2013/12/30 Javascript
Firefox中使用outerHTML的2种解决方法
2014/06/07 Javascript
Javascript实现飞动广告效果的方法
2015/05/25 Javascript
Jquery 分页插件之Jquery Pagination
2015/08/25 Javascript
基于jQuery实现的向下滑动二级菜单效果代码
2015/08/31 Javascript
jQuery实现有动画淡出效果的二级折叠菜单代码
2015/10/17 Javascript
简单的js表格操作
2016/09/24 Javascript
KnockoutJS 3.X API 第四章之click绑定
2016/10/10 Javascript
JS实现浏览上传文件的代码
2017/08/23 Javascript
vue2.0安装style/css loader的方法
2018/03/14 Javascript
.vue文件 加scoped 样式不起作用的解决方法
2018/05/28 Javascript
JavaScript实现的DOM绘制柱状图效果示例
2018/08/08 Javascript
js找出5个数中最大的一个数和倒数第二大的数实现方法示例小结
2020/03/04 Javascript
python生成二维码的实例详解
2017/10/29 Python
python opencv实现任意角度的透视变换实例代码
2018/01/12 Python
python3 爬取图片的实例代码
2018/11/06 Python
pycharm运行scrapy过程图解
2019/11/22 Python
Python基础之变量基本用法与进阶详解
2020/01/03 Python
python3跳出一个循环的实例操作
2020/08/18 Python
PyCharm 2020.2下配置Anaconda环境的方法步骤
2020/09/23 Python
HTML5进度条特效
2014/12/18 HTML / CSS
浅谈HTML5新增和废弃的标签
2019/04/28 HTML / CSS
为娇小女性量身打造：Petite Studio
2018/11/01 全球购物
系统管理员的职责包括那些？管理的对象是什么？
2013/01/18 面试题
大专学生推荐信范文
2013/11/19 职场文书
留学推荐信中文范文三篇
2014/01/25 职场文书
就业意向书范文
2014/04/01 职场文书
初中优秀学生评语
2014/12/29 职场文书
高三毕业感言
2015/07/30 职场文书
大学文艺委员竞选稿
2015/11/19 职场文书
学校学习型党组织建设心得体会
2019/06/21 职场文书
为什么你写的height:100%不起作用
2021/05/10 HTML / CSS
vue实现简易音乐播放器
2022/08/14 Vue.js
微软Win11 全新照片应用面向 Dev预览版推出 新版本上手体验图集
2022/09/23 数码科技