How to do python class like pygame.Rect?

Question

I was wondering, how to do python class like pygame.Rect. What i mean by that is how to make a class where, when you change one variable, the others change as well ( with pygame Rect you can change for example variable x and automaticly variable centerx changes to adapt )

Does [this](https://stackoverflow.com/questions/6190468/how-to-trigger-function-on-value-change) answer your question? You can also change the variable in the function before you use it. For example, a variable like `centerx`, it is always proportionate to `x` so you can set `centerx` to a value based on `x` before using `centerx` in the function. — Orbital, May 16 '21 at 11:43

score 1 · Answer 1 · answered May 16 '21 at 12:22

You're talking about property setters and getters! Here's a toy example with a circle:

import math

class Circle:
    def __init__(self, radius):
        self._radius = radius
        self.update_from_radius()

    @property
    def radius(self):
        return self._radius

    @radius.setter
    def radius(self, val):
        self._radius = val
        self.update_from_radius()

    def update_from_radius(self):
        self.area = self._radius*self._radius*math.pi
        self.circumference = 2*self._radius*math.pi
        self.diameter = 2*self._radius

c = Circle(4)
print(c.area) >>> 50.26548245743669

c.radius = 8
print(c.area) >>> 201.06192982974676

If you want to learn more, have a look here, which gives a pretty good explanation.

How to do python class like pygame.Rect?

1 Answers1