title: Drag & Drop not working properly on Retina iPad (createjs)
body: <p>I want to create a simple drag &amp; drop exercise, but on the Retina iPad "drag &amp; drop" is not working properly.
  Here is the code:</p>
  
  <pre><code>var that = this;
  createjs.Touch.enable(stage);
  stage.enableMouseOver(10);
  
  function initPage() {
    var shape = new createjs.Shape();
    shape.graphics.beginFill("#999999").drawRoundRect(100,100,140,60,8).endFill();
    shape.on("mousedown", function(evt) {
      this.alpha = 0.8;
      this.offset = {x: this.x - evt.stageX, y: this.y - evt.stageY};
    });
  
    shape.on("pressmove", function(evt) {
      this.x = evt.stageX + this.offset.x;
      this.y = evt.stageY + this.offset.y;
    });
  
    shape.on("pressup", function(evt) {
      this.alpha = 1;
    });
  
    that.addChild(shape);
  }
  
  initPage();
  </code></pre>
  
  <p>I can drag the shape, but the more I move it, the more it moves away from my finger. Here is a video I just recorded:
  <a href="https://dl.dropboxusercontent.com/u/11697167/animatecc-bug.mp4" rel="nofollow noreferrer">https://dl.dropboxusercontent.com/u/11697167/animatecc-bug.mp4</a></p>
  
  <p>I'm working with Adobe Animate CC, and the exported HTML file contains the following code to make it look good on high-res screens like the Retina iPad:</p>
  
  <pre><code>//Code to support hidpi screens and responsive scaling.
  function makeResponsive(isResp, respDim, isScale, scaleType) {      
      var lastW, lastH, lastS=1;      
      window.addEventListener('resize', resizeCanvas);        
      resizeCanvas();     
      function resizeCanvas() {           
          var w = lib.properties.width, h = lib.properties.height;            
          var iw = window.innerWidth, ih=window.innerHeight;          
          var pRatio = window.devicePixelRatio || 1, xRatio=iw/w, yRatio=ih/h, sRatio=1;          
          if(isResp) {                
              if((respDim=='width'&amp;&amp;lastW==iw) || (respDim=='height'&amp;&amp;lastH==ih)) {                    
                  sRatio = lastS;                
              }               
              else if(!isScale) {                 
                  if(iw&lt;w || ih&lt;h)                        
                      sRatio = Math.min(xRatio, yRatio);              
              }               
              else if(scaleType==1) {                 
                  sRatio = Math.min(xRatio, yRatio);              
              }               
              else if(scaleType==2) {                 
                  sRatio = Math.max(xRatio, yRatio);              
              }           
          }           
          canvas.width = w*pRatio*sRatio;         
          canvas.height = h*pRatio*sRatio;
          canvas.style.width = preloaderDiv.style.width = w*sRatio+'px';              
          canvas.style.height = preloaderDiv.style.height = h*sRatio+'px';
          stage.scaleX = pRatio*sRatio;           
          stage.scaleY = pRatio*sRatio;           
          lastW = iw; lastH = ih; lastS = sRatio;     
      }
  }
  makeResponsive(false,'both',false,1);   
  </code></pre>
  
  <p>If I remove the resizeCanvas function, drag &amp; drop is working fine on the iPad but the resolution is MUCH worse.</p>
  
  <p>Any ideas for a workaround?</p>