Trait widgetry::WidgetImpl

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pub trait WidgetImpl: Downcast {
    // Required methods
    fn get_dims(&self) -> ScreenDims;
    fn set_pos(&mut self, top_left: ScreenPt);
    fn event(&mut self, ctx: &mut EventCtx<'_>, output: &mut WidgetOutput);
    fn draw(&self, g: &mut GfxCtx<'_>);

    // Provided methods
    fn can_restore(&self) -> bool { ... }
    fn restore(&mut self, _: &mut EventCtx<'_>, _prev: &dyn WidgetImpl) { ... }
}
Expand description

Create a new widget by implementing this trait. You can instantiate your widget by calling Widget::new(Box::new(instance of your new widget)), which gives you the usual style options.

Required Methods§

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fn get_dims(&self) -> ScreenDims

What width and height does the widget occupy? If this changes, be sure to set redo_layout to true in event.

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fn set_pos(&mut self, top_left: ScreenPt)

Your widget’s top left corner should be here. Handle mouse events and draw appropriately.

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fn event(&mut self, ctx: &mut EventCtx<'_>, output: &mut WidgetOutput)

Your chance to react to an event. Any side effects outside of this widget are communicated through the output.

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fn draw(&self, g: &mut GfxCtx<'_>)

Draw the widget. Be sure to draw relative to the top-left specified by set_pos.

Provided Methods§

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fn can_restore(&self) -> bool

If a new Panel is being created to replace an older one, all widgets have the chance to preserve state from the previous version.

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fn restore(&mut self, _: &mut EventCtx<'_>, _prev: &dyn WidgetImpl)

Restore state from the previous version of this widget, with the same ID. Implementors must downcast.

Implementations§

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impl dyn WidgetImpl

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pub fn is<__T: WidgetImpl>(&self) -> bool

Returns true if the trait object wraps an object of type __T.

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pub fn downcast<__T: WidgetImpl>(self: Box<Self>) -> Result<Box<__T>, Box<Self>>

Returns a boxed object from a boxed trait object if the underlying object is of type __T. Returns the original boxed trait if it isn’t.

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pub fn downcast_rc<__T: WidgetImpl>(self: Rc<Self>) -> Result<Rc<__T>, Rc<Self>>

Returns an Rc-ed object from an Rc-ed trait object if the underlying object is of type __T. Returns the original Rc-ed trait if it isn’t.

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pub fn downcast_ref<__T: WidgetImpl>(&self) -> Option<&__T>

Returns a reference to the object within the trait object if it is of type __T, or None if it isn’t.

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pub fn downcast_mut<__T: WidgetImpl>(&mut self) -> Option<&mut __T>

Returns a mutable reference to the object within the trait object if it is of type __T, or None if it isn’t.

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