28 lines
838 B
Python
28 lines
838 B
Python
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'''
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Opacity scroll effect
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=====================
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Based on the :class:`~kivy.effects.damped.DampedScrollEffect`, this one will
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also decrease the opacity of the target widget during the overscroll.
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'''
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__all__ = ('OpacityScrollEffect', )
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from kivy.effects.dampedscroll import DampedScrollEffect
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class OpacityScrollEffect(DampedScrollEffect):
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'''OpacityScrollEffect class. Uses the overscroll
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information to reduce the opacity of the scrollview widget. When the user
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stops the drag, the opacity is set back to 1.
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'''
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def on_overscroll(self, *args):
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if self.target_widget and self.target_widget.height != 0:
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alpha = (1.0 -
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abs(self.overscroll / float(self.target_widget.height)))
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self.target_widget.opacity = min(1, alpha)
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self.trigger_velocity_update()
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