Python | Multiple Sliders widgets Controlling Background Screen or WindowColor in Kivy

Last Updated : 19 Oct, 2021

Prerequisite - Slider in Kivy
Kivy is a platform independent GUI tool in Python. As it can be run on Android, IOS, linux and Windows etc. It is basically used to develop the Android application, but it does not mean that it can not be used on Desktops applications.
In this article, we will learn How we can control the background color in kivy that means if we slide the slider the color of window changes accordingly.
There are many different methods by which you can make this. Let's see one simple approach.

???????? Kivy Tutorial - Learn Kivy with Examples.

Basic Approach to make it is very simple:
1) import kivy
2) import kivyApp
3) import BoxLayout
4) set minimum version(optional)
5) Extend the class
6) set up .kv file :
        -> Set orientation
        -> Set slider color
        -> Create canvas.before property
        -> Create Sliders
        -> Create label
7) Return layout
8) Run an instance of the class

How multiple Sliders Controlling Background Color in Kivy ?

Python3

# main.py to manipulate the window 
# color or screen colour in kivy

# base Class of your App inherits from the App class.  
# app:always refers to the instance of your application  
from kivy.app import App

# BoxLayout arranges children in a vertical or horizontal box. 
# or help to put the childrens at the desired location. 
from kivy.uix.boxlayout import BoxLayout 

# creating the root widget used in .kv file 
class MultipleSliderWidget(BoxLayout):
    pass

# class in which name .kv file must be named Slider.kv.
# or creating the App class
class Multiple_Slider(App):
    def build(self):
        # returning the instance of SliderWidget class 
        return MultipleSliderWidget()

# run the app    
if __name__ == '__main__':
    Multiple_Slider().run()

Now the .kv file of the above code is -

Python3

# Multiple_Slider.kv file of the main.py file.

#.kv file to manipulate the window colour.
<MultipleSliderWidget>:
    
    # giving the orientation of Slider
    orientation: "vertical"

    # initially providing this colour to window
    slider_colors: 0.5, 0.5, 0.5

    # executed before the canvas group.
    canvas.before:
        Color:
            rgb: root.slider_colors
        Rectangle:
            pos: root.pos
            size: root.size
            
    # creating the Slider
    Slider:
        min: 0  # minimum value of Slider
        max: 1 # maximum value of Slider
        value: 0.5  # initial value of Slider
        
        # when slider moves then to increase value
        on_value: root.slider_colors[0] = self.value;

    Slider:
        min: 0
        max: 1
        value: 0.5
        on_value: root.slider_colors[1] = self.value

    Slider:
        min: 0
        max: 1
        value: 0.5
        on_value: root.slider_colors[2] = self.value

    # Adding The label 
    Label:
        font_size: "30sp"
        # the for loop is for continuously changing
        # the colour as slider value changes
        text: "Color:" + ", ".join(["%.3f" %(i) for i in root.slider_colors]) 
        color: 0, 0, 1, 1