How to remove a specific Rectangle in Kivy?

Question

I want to know how to remove a specific Rectangle object in Kivy. I create the Rectangle in .py file by pressing a button and I want to the second button could be able to remove that specific Rectangle. My .py code:

import kivy
kivy.require("1.10.1")
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.screenmanager import ScreenManager, Screen, FadeTransition
from kivy.uix.button import Button
from kivy.uix.label import Label
from kivy.lang import Builder
from kivy.app import App
from kivy.graphics import RoundedRectangle



class Screen1(Screen):
    def create_on_press(self):
        with self.canvas:
            RoundedRectangle(pos = (770, 1250), size = (400, 400), size_hint = (None, None), source = "Rectangle.jpeg")
    
    def remove_on_press(self):
        pass #I don't know what to write there
            

class Test(App):
    def build(self):
        Builder.load_file("Test.kv")
        sm = ScreenManager(transition = FadeTransition())
        sm.add_widget(Screen1(name = "scr1"))
        return sm
        
Test().run()

And the .kv file:

#: kivy 1.10.1

<Screen1>:
    
    id: scr1
    
    orientation: "vertical"
    canvas.before:
        Rectangle:
            pos: self.pos
            size: self.size
            source: "Background.png"
        
    Button:
        pos: (root.width - 600) / 2, 800
        size: 600, 200
        text: "Create rectangle"
        on_press: scr1.create_on_press()
        pos_hint: {'width': 0.5, 'top': 0.8}
        size_hint: None, None
        
    Button:
        pos: (root.width - 600) / 2, 200
        size: 600, 200
        text: "Remove rectangle"
        on_press: scr1.remove_on_press
        pos_hint: {'width': 0.5, 'top': 0.2}
        size_hint: None, None

Thanks for any help.

I tried to use self.parent.remove_widget, but it removed the whole Screen1. However, I want to remove only this Rectangle.

Answer 1

One of the various ways can be adding a group attr. and remove that group later. Since RoundedRectangle is inherited from class Instruction, you can set its attr. group and later use method remove_group to remove that particular group as follows,

    def create_on_press(self):
        with self.canvas:
            RoundedRectangle(pos = (770, 1250), size = (400, 400), size_hint = (None, None), source = "Rectangle.jpeg", group = u"rect")

    def remove_on_press(self):
        self.canvas.remove_group(u"rect")

Also an obvious change you need in .kv,

    ...
    Button:
        pos: (root.width - 600) / 2, 200
        size: 600, 200
        text: "Remove rectangle"
        on_press: scr1.remove_on_press() # Call the function.
        ...