Using methods of classes that its didn't extends the same parent class

Question

I'm using Processing, and I have a method ( smooth() here) that I would like to use for PApplet object when I draw in the window and for PGraphics when I draw in a image.

The problem is, theses two classes ( PApplet & PGraphics ) extends only from the Object class and Eclipse said I must choice between the PApplet cast or the PGraphics cast but i want to use both in this case.

How can I fix that ?

Answer 1

There isn't a magical way to support two completely different types. There are a couple workarounds though.

You could use overloading which means creating separate functions for each type. Something like this:

void drawRect(PGraphics pg){
  pg.rect(1, 2, 3, 4);
}

void drawRect(PApplet p){
  p.rect(1, 2, 3, 4);
}

Or you could rely on the fact that the PApplet class has a g variable that references its internal PGraphics instance. Then you'd only need one function that takes a PGraphics and pass in the g variable when you had a PApplet instance. Something like this:

void setup(){
 size(500, 500); 
}

void draw(){
 drawCircle(g); 
}

void drawCircle(PGraphics pg){
  pg.ellipse(mouseX, mouseY, 20, 20);
}

This approach is a bit hacky, so an even better solution would be to refactor your PApplet code so it always draws to a PGraphics explicitly. Then you could pass that PGraphics instance to your function.