Well, I am planning to make something complex. Ok, I still have not done it but I want to know how to proceed to do it. Suppose there is a Canvas, and I am dragging and dropping images in it which can resize. The issue is not on the drag/drop and resize stuffs.

What I want is, once an image is in the Canvas, how to write on it by double click? I mean if I double click, the cursor turn to text and people can write. How to proceed to do this?

The canvas will be saved in image format later. All I want to know now, is this writing stuff, the rest I do not care too much now!
Thank