In repaint! allow specifying region to repaint

[m-r-hunt]

I've been doing some custom painting, and I was having some performance problems. I'm in a situation where I know I only need to repaint a small area of my canvas, but the repaint! macro causes a full repaint of the whole canvas. I tried conspiring behind it's back to only repaint the region I know needs painting, but the rest of the canvas gets blanked out.

After searching the swing docs, it looks like the solution is to specify a dirty region to repaint, rather than repainting the whole component. There's no way to do this (as far as I can tell) in seesaw, the repaint! function always repaints whole components.

I can solve my problem (I think) by manually calling the swing repaint methods, but it would be nice if there was a seesaw way to do this.

[m-r-hunt]

Proposed function:

(repaint-region! [widget1 rect1] [widget2 rect2] ...)

or something like that.

[m-r-hunt]

Gif of what happens when you try to be too clever for your own good:

[m-r-hunt]

Here's the core of a method to do this. I'm too tired to make it work nicely with multiple widgets/rectangles right now.

Yes you have to deconstruct the rectangle like that because java.awt.component repaint methods won't take a java.awt.rectangle2D, only x y w h in the argument list. (I think it makes sense for the seesaw interface to take a seesaw.graphics/rect even though the underlying swing/awt code is dumb)

(defn repaint-region!
  "Repaint only a specified rectangle"
  [widget rect]
  (.repaint (seesaw.core/to-widget widget) 
            (.getX rect) 
            (.getY rect) 
            (.getWidth rect) 
            (.getHeight rect)))