Circular (Oval like) button using canvas in kivy (using .kv file)

Circular (Oval like) button using canvas in kivy (using .kv file)

To create a circular or oval-like button in Kivy using the .kv file and a Canvas, you can use Ellipse within a Widget. You will not directly use the Button widget since it is rectangular, but you can create a custom widget that behaves like a button.

Below is an example of how you could implement a circular button using Kivy's Canvas:

Python File (main.py):

from kivy.app import App from kivy.uix.widget import Widget from kivy.properties import ListProperty class CircularButton(Widget): # You can use ListProperty to listen for color changes button_color = ListProperty([1, 0, 0, 1]) # Red color def on_touch_down(self, touch): if self.collide_point(*touch.pos): # Change color to indicate a press self.button_color = [0, 1, 0, 1] # Green color return True return super(CircularButton, self).on_touch_down(touch) def on_touch_up(self, touch): if self.collide_point(*touch.pos): # Perform the action of the button print("Circular button pressed!") # Change the color back to the default self.button_color = [1, 0, 0, 1] # Red color return True return super(CircularButton, self).on_touch_up(touch) class CircularButtonApp(App): def build(self): return CircularButton() if __name__ == '__main__': CircularButtonApp().run()

KV File (circularbutton.kv):

<CircularButton>: size: 100, 100 # Size of the circular button canvas.before: Color: rgba: self.button_color Ellipse: pos: self.pos size: self.size

In this code:

  • CircularButton is a custom widget that has a button_color property. The on_touch_down and on_touch_up methods are overridden to handle touch events.
  • When a touch is detected within the widget's bounds (collide_point), the color is changed to give visual feedback.
  • The .kv file draws an Ellipse using Canvas.before, which is colored according to the button_color property.
  • The size of the CircularButton widget is set to 100x100, which is also the size of the Ellipse.

The CircularButton does not inherit from Button, but you can add more functionality to make it behave more like a button, such as on_press and on_release events.

When you run this Kivy application, you'll see a red circular button. When you click the button, it will turn green, and when you release the button, it will turn back to red, printing a message to the console.

To make the button more oval-like, you can simply change the size property to have different width and height values. For instance, size: 150, 100 will make it an oval shape wider than it is tall.

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