touchgfx::CanvasWidget::invalidate() const method

@fn virtual void CanvasWidget::invalidate() const; Invalidates the area covered by this CanvasWidget. Invalidates the area covered by this CanvasWidget. Since many widgets are a lot smaller than the actual size of the canvas widget, each widget must be able to tell the smallest rectangle completely containing the shape drawn by the widget. For example a circle arc is typically much smaller than the widget containing the circle. @see getMinimalRect()