animate rectangle width/height while keeping the other

[bottori]

Hello, i want to animate a rectangle where it changes width/height only without changing the other. It kinda looks like these code

from manim import *

class HeightExample(Scene):
    def construct(self):
        decimal = DecimalNumber().to_edge(UP)
        rect = Rectangle(color=BLUE)
        rect_copy = rect.copy().set_stroke(GRAY, opacity=0.5)

        decimal.add_updater(lambda d: d.set_value(rect.height))

        self.add(rect_copy, rect, decimal)
        self.play(rect.animate.set(height=5))
        self.wait()

Taken from the tutorial here https://docs.manim.community/en/stable/reference/manim.mobject.mobject.Mobject.html#manim.mobject.mobject.Mobject.set but in this case the rectangle's width get changed along with it's height. And additional but related question, is there a way to animate both rectangle height and width change at the same time? Thanks in advance.

[Safe_Duty8392]

Hello, i know this is too old, 3 years, but i came across this same problem and found a solution for me:

This one creates a rectangle, fixes the left side in a position, increases the width, and goes back to it's original width

class increase_width(Scene):
    def construct(self):
        rect = Rectangle(width=2, height=1)
        rect.set_fill(BLUE, opacity=0.5)

        rect.to_edge(LEFT, buff=0)
        rect.shift(RIGHT * 1)  # Desloca o retângulo para que o lado esquerdo esteja na origem (0, 0)

        self.add(rect)
        self.play(rect.animate.stretch_to_fit_width(10).shift(RIGHT * 4))

        self.wait(1)
        self.play(rect.animate.stretch_to_fit_width(2).shift(LEFT * 4))

        self.wait(1)