Animation Basics - Kivy Animation

Introduction

Kivy is an open source Python library used for building multi-touch applications with a natural user interface. One of the core features of Kivy is its built-in support for animation. In this tutorial, we will learn the basics of animation in Kivy.

Syntax

The basic syntax for creating an animation in Kivy is as follows:

from kivy.animation import Animation
from kivy.uix.widget import Widget

widget = Widget()

# Create an animation object and define properties to animate over
animation = Animation(pos=(200, 200), size=(400, 400), duration=2)

# Start the animation
animation.start(widget)

Example

Let's create a simple example to understand the basics of Kivy animation. We'll create a rectangle that will move from the left edge of the window to the right edge over a period of 3 seconds.

from kivy.app import App
from kivy.uix.widget import Widget
from kivy.animation import Animation


class MyWidget(Widget):
    def animate(self, widget):
        animation = Animation(x=self.width - widget.width, duration=3)
        animation.start(widget)

class MyApp(App):
    def build(self):
        widget = MyWidget()
        widget.size_hint = (None, None)
        widget.width = 100
        widget.height = 50

        widget.animate(widget)

        return widget

if __name__ == '__main__':
    MyApp().run()

Output

When you run the above code, you'll see a rectangle moving from the left edge of the window to the right edge over a period of 3 seconds.

Explanation

In the above example, we first created a MyWidget class that inherits from the Kivy Widget class. We added an animate() method to the class to define the animation. In the animate() method, we created an Animation object that animates the x property of a given widget to the value of self.width - widget.width over a period of 3 seconds. We then started the animation with the start() method.

In the MyApp class, we instantiated a MyWidget object and assigned it to the widget variable. We set the size hint to (None, None) to allow us to explicitly set the width and height of the widget. We then set the width and height of the widget to 100 pixels and 50 pixels, respectively. Finally, we called the animate() method on the widget to start the animation.

Uses

The animation capabilities in Kivy can be used to create complex, multi-step animations to enhance the user experience of your applications. You can animate any property of a widget, including size, position, color, and opacity.

Important Points

• Animations in Kivy use an Animation object to define the properties to be animated and the duration of the animation.
• You can animate any property of a widget, including size, position, color, and opacity.
• Multiple animations can be chained together to create more complex animations.
• Animations can also be triggered by user input or events.

Summary

Kivy animation is a powerful feature that can be used to enhance the user experience of your applications. The Animation object is used to define the properties to be animated and the duration of the animation. You can animate any property of a widget, including size, position, color, and opacity, and multiple animations can be chained together to create more complex animations. Animations can also be triggered by user input or events.