javascript - How do I get reference of old generated elements in HTML Canvas?

Question

Take a look at this example:

  var c=document.getElementById("myCanvas");
   var ctx=c.getContext("2d");

    // First rectangle created    
    ctx.fillRect(20,20,150,100);

    // Second rectangle created    
    ctx.fillRect(20,150,150,100);

    // Third rectangle created    
    ctx.fillRect(20,300,150,100);

I created three rectangles here. After creating third rectangle I want to rotate first rectangle. How do i get reference of first rectangle now?

Answer 1

You don't "get the reference" of a rectangle or something with canvas. All you have is a canvas with a context. On which you can draw. Period.

If you want to move the first rectangle, then clear it (using clearRect) and redraw the new one.