RoundedRectangle doesn't update when width or height == 0

[tshirtman]

Versions

• Python:
• OS: ubuntu
• Kivy: 1.11.0-dev (a33ed47)
• Kivy installation method: git

Description

If a RoundedRectangle's size changes and one of the size's component is 0, then the build function exists early, and the vertex instruction is not updated, instead, the method should probably just batch an empty set of instructions (or minimal), so the previously displayed vertices are replaced.

Code and Logs

from kivy.app import App
from kivy.lang import Builder
from kivy.properties import BooleanProperty


KV = '''
BoxLayout:
    Button:
        text: 'hide' if app.show else 'show'
        on_press: app.show = not app.show

    Widget:
        canvas:
            RoundedRectangle:
                pos: self.pos
                size: self.width, self.height if app.show else 0
                radius: 10, 10, 10, 10
'''

class MApp(App):
    show = BooleanProperty(False)

    def build(self):
        return Builder.load_string(KV)

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