Custom Transition in Python

[Lord Hisu]

I'm trying to move a custom displayable with keyboard input using MoveTransition in Python.
I already know how to move the displayable without the transition, by changing the blit position. I have a parent class and two children, all displayables. Here's my render method of the parent. Please point out if I'm doing something wrong with the width and height arguments, I'm not sure yet of what area I should pass to the children, since I failed to notice anything changing at all.

Code: Select all

def render(self, width, height, st, at):
            canvas = renpy.Render(width, height)
            
            # This method updates the children with the consequences of the keyboard input,
            # changing their positions.
            self.check_movement()
            
            render_map = renpy.render(self.map_base, width, height, st, at)
            render_char = renpy.render(self.char, width, height, st, at)
            canvas.blit(render_map, (0,0))
            canvas.blit(render_char, (0,0))
            
            renpy.redraw(self, 0)
            return canvas

What I want is not to alter the positions of the children directly, but to apply a MoveTransition that move the children from A to B given the delay.
I can't quite understand this part of the documentation, what I do understand is that I need to renpy.render a displayable, and blit that render to the parent's render, that needs to be returned. I successfully applied Transforms too, but the transition part is still kind of confusing.

Can someone show me a simple working render method that applies a MoveTransition?
And if possible, explain step by step what is happening, what is returning what, and so on.

Thank you in advance!

[PyTom]

You don't really want to use MoveTransition. What you want to do here is to use the information you have to blit render_char at a different offset.

[Lord Hisu]

You don't really want to use MoveTransition. What you want to do here is to use the information you have to blit render_char at a different offset.

That's what I want, but I thought a transition would do that for me.
I could do that manually, yes, but in this case I think I'm misunderstanding transitions.
Can you please clarify that for me?