title: How to draw shapes interactively on top of a HTML5 canvas?
body: <p>I need to draw a shape on top of a HTML5 canvas with the mouse cursor, like a square or a circle; and it should be resizable, then, when the user has finished with the drawing, the coordinates of the shape inside the canvas should be retrievable.</p>
  
  <p>Any ideas of how can I achieve this using JavaScript?</p>
  
  <p>Thanks</p>