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
JavaScript表单常用验证集合
Jan 16 Javascript
jQuery 插件 将this下的div轮番显示
Apr 09 Javascript
js类型检查实现代码
Oct 29 Javascript
面向对象Javascript核心支持代码分享
May 23 Javascript
jQuery的显示和隐藏方法与css隐藏的样式对比
Oct 18 Javascript
如何在Linux上安装Node.js
Apr 01 Javascript
使用AJAX实现Web页面进度条的实例分享
May 06 Javascript
AngularJS 指令详细介绍
Jul 27 Javascript
require.js+vue开发微信上传图片组件
Oct 27 Javascript
浅谈箭头函数写法在ReactJs中的使用
Aug 22 Javascript
jQuery实现的下雪动画效果示例【附源码下载】
Feb 02 jQuery
Vue自定义组件双向绑定实现原理及方法详解
Sep 03 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
说明书(38) 检举信(8) 协议书(568) 工作总结(1972) 标语(336) 口号(179) 党团范文(807) 任命书(51) 公证书(45) 报告(147)
You might like
全国FM电台频率大全 - 28 甘肃省
2020/03/11 无线电
浅谈PHP表单提交(POST&amp;GET&amp;URL编/解码)
2017/04/03 PHP
Laravel 解决composer相关操作提示php相关异常的问题
2019/10/23 PHP
php ZipArchive实现多文件打包下载实例
2019/10/31 PHP
另类调用flash无须激活的方法
2006/12/27 Javascript
JavaScript 函数式编程的原理
2009/10/16 Javascript
基于jQuery的树控件实现代码(asp.net+json)
2010/07/11 Javascript
Ajax 数据请求的简单分析
2011/04/05 Javascript
JQuery 返回布尔值Is()条件判断方法代码
2012/05/14 Javascript
给jQuery方法添加回调函数一款插件的应用
2013/01/21 Javascript
jquery点击页面任何区域实现鼠标焦点十字效果
2013/06/21 Javascript
多选列表框动态添加,移动,删除,全选等操作的简单实例
2014/01/13 Javascript
ie8模式下click无反应点击option无反应的解决方法
2014/10/11 Javascript
轻松创建nodejs服务器（8）：非阻塞是如何实现的
2014/12/18 NodeJs
JavaScript中的逻辑判断符&amp;&amp;、||与!介绍
2014/12/31 Javascript
JavaScript检测鼠标移动方向的方法
2015/05/22 Javascript
js中的内部属性与delete操作符介绍
2015/08/10 Javascript
jQuery validate插件实现ajax验证重复的2种方法
2016/01/22 Javascript
微信小程序页面滑动屏幕加载数据效果
2020/11/16 Javascript
NodeJS实现视频转码的示例代码
2017/11/18 NodeJs
利用PHP实现递归删除链表元素的方法示例
2020/10/23 Javascript
[03:31]DOTA2英雄基础教程 大地之灵
2013/12/17 DOTA
python字符串加密解密的三种方法分享(base64 win32com)
2014/01/19 Python
python实现的系统实用log类实例
2015/06/30 Python
Python遍历目录中的所有文件的方法
2016/07/08 Python
Python3 模块、包调用&amp;路径详解
2017/10/25 Python
python正则表达式re之compile函数解析
2017/10/25 Python
python 移除字符串尾部的数字方法
2018/07/17 Python
解决Python找不到ssl模块问题 No module named _ssl的方法
2019/04/29 Python
Flask框架重定向,错误显示,Responses响应及Sessions会话操作示例
2019/08/01 Python
python实现控制台输出颜色
2021/03/02 Python
中东奢侈品购物网站：Ounass
2020/09/02 全球购物
公司营业员的自我评价
2014/03/04 职场文书
井冈山红色之旅感想
2014/10/07 职场文书
2014年学校党建工作总结
2014/11/11 职场文书
七年级作文之《我和我的祖国》观后感作文
2019/10/18 职场文书