如何实时获取鼠标的当前坐标

互联网 18-5-11
本文来做一个简单的实时获取鼠标坐标的功能,在canvas动画开发中,获取鼠标的坐标,键盘的按键等等,都是常用的操作,我们就慢慢得把他们封装成一个公共库。

一、事件的兼容:

function bindEvent(obj, event, fn) {          if (obj.attachEvent) { //ie              obj.attachEvent('on' + event, function () {                  fn.call(obj);              });          } else {              //chrome&ff              obj.addEventListener(event, fn, false);          }      }

上面兼容ie8以及修正this关键字在ie低版本的指向,下面兼容chrome和ff。其他更常用的封装可以参考我的javascript开源框架gdom

二、用立即表达式搭建一个基本的库

添加获取鼠标坐标的方法

;(function (window) {      window.G = {};      function bindEvent(obj, event, fn) {          if (obj.attachEvent) { //ie              obj.attachEvent('on' + event, function () {                  fn.call(obj);              });          } else {              //chrome&ff              obj.addEventListener(event, fn, false);          }      }        G.getPos = function( dom ){          var oPos = { x : 0, y : 0 };          bindEvent( dom, 'mousemove', function( ev ){              var oEvent = ev || event, x, y;              if ( oEvent.pageX || oEvent.pageY ){                  x = oEvent.pageX;                  y = oEvent.pageY;              }else {                  x = oEvent.clientX + document.body.scrollLeft || document.documentElement.scrollLeft;                  y = oEvent.clientX + document.body.scrollTop || document.documentElement.scrollTop;              }              x -= dom.offsetLeft;              y -= dom.offsetTop;              oPos.x = x;              oPos.y = y;          } );          return oPos;      };    })(window);

三、引入封装的js库,绑定canvas为监听对象,打印当前鼠标的坐标

鼠标的坐标,我这里画了2根线,便于观察.

<head>  <meta charset='utf-8' />  <script>  ;(function (window) {      window.G = {};      function bindEvent(obj, event, fn) {          if (obj.attachEvent) { //ie              obj.attachEvent('on' + event, function () {                  fn.call(obj);              });          } else {              //chrome&ff              obj.addEventListener(event, fn, false);          }      }        G.getPos = function( dom ){          var oPos = { x : 0, y : 0 };          bindEvent( dom, 'mousemove', function( ev ){              var oEvent = ev || event, x, y;              if ( oEvent.pageX || oEvent.pageY ){                  x = oEvent.pageX;                  y = oEvent.pageY;              }else {                  x = oEvent.clientX + document.body.scrollLeft || document.documentElement.scrollLeft;                  y = oEvent.clientX + document.body.scrollTop || document.documentElement.scrollTop;              }              x -= dom.offsetLeft;              y -= dom.offsetTop;              oPos.x = x;              oPos.y = y;          } );          return oPos;      };    })(window);  </script>  <style>  #canvas{      border:1px dashed #aaa;  }  </style>  <script>  window.onload = function(){      var oCanvas = document.querySelector( "#canvas" ),          oGc = oCanvas.getContext( '2d' ),          width = oCanvas.width, height = oCanvas.height,          oInfo = document.querySelector( "#info" ),          oPos = G.getPos( oCanvas );          oCanvas.addEventListener( "mousemove", function(){                            oGc.clearRect( 0, 0, width, height );              oGc.beginPath();              oGc.moveTo( oPos.x, 0 );              oGc.lineTo( oPos.x, height );              oGc.moveTo( 0, oPos.y );              oGc.lineTo( width, oPos.y );              oGc.closePath();              oGc.strokeStyle = '#09f';              oGc.stroke();                oInfo.innerHTML = '鼠标的当前坐标是:(' + oPos.x + ',' + oPos.y + ')';          }, false );  }  </script>  </head>  <body>  <canvas id="canvas" width="500" height="400"></canvas>  <p id="info"></p>  </body>

以上就是如何实时获取鼠标的当前坐标 的详细内容,更多内容请关注技术你好其它相关文章!

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