• 使用JavaScript实现使用鼠标画线的效果


    <!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=utf-8" />  
    <title>Untitled 1</title>  
    <style type="text/css">  
    .style1 {  
        font-size: x-small;  
    }  
    </style> 
    <script type="text/javascript">  
    /**
        画点
    */    
    function makedot(x, y){ 
      pointDiv = "<div style='height:1px;position:absolute;left:" + x +
          "px;top:" + y + "px;1px;background:#f00;overflow:hidden'></div>"; 
      return pointDiv;
    } 
    /**  
      根据两点坐标画直线。  
    */  
    
    function line(x1,y1,x2,y2){  
      var slope; //斜率
      var direction;//坐标运动方向
      var tx = x2 - x1;
      var ty = y2 - y1;
      if(tx == 0 && ty == 0)return;
      var points = "";
      var axis;//坐标轴上的坐标
      if(Math.abs(tx) >= Math.abs(ty)){//在x轴上移动
          direction = tx > 0 ? 1 : -1;
          tx = Math.abs(tx);
          slope = ty / tx;
          axis = x1;
          for(i = 0; i < tx; i ++){
              points += makedot(axis, y1 + i * slope);
              axis += direction;
          }
            
      }else{//在y轴上移动
          direction = ty > 0 ? 1 : -1;
          ty = Math.abs(ty);
          slope = tx / ty;  
          axis = y1;    
          for(i = 0; i < ty; i ++){
              points += makedot(x1 + i * slope, axis);
              axis += direction;
          }
      }
      var container = document.getElementById("container");
      container.innerHTML += points; 
    } 
    var oldPoint = null;
    //获取鼠标位置
    function mousePosition(ev){
        ev = ev || window.event;
        if(ev.pageX || ev.pageY){
            return {x:ev.pageX, y:ev.pageY};
        }
        var doc = document.documentElement, body = document.body;
        var pageX = event.clientX + (doc && doc.scrollLeft || body && body.scrollLeft || 0) - (doc && doc.clientLeft || body && body.clientLeft || 0);
        var pageY = event.clientY + (doc && doc.scrollTop  || body && body.scrollTop  || 0) - (doc && doc.clientTop  || body && body.clientTop  || 0);        
        return {x:pageX, y:pageY};
    }
    
    function recordPoint(ev){
        
        var point = mousePosition(ev);
        if(oldPoint != null){
            line(oldPoint.x, oldPoint.y, point.x, point.y);
        }
        oldPoint = point;
    }
    
    
    </script>
    </head>  
    
    <body>  
    <div id="container" style=" 1000px; height: 600px; border:1px #bfbfbf solid;" onclick="recordPoint(event);">
        
    </div>
    <script type="text/javascript"> 
        //line(19,19,22,300); 
    </script>
    </body>  
    
    </html> 
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  • 原文地址:https://www.cnblogs.com/ranran/p/3896341.html
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