public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();

            OpacityImageBrush = GetTemplateChild(ButtonBaseConstants.OpacityImageBrushName) as ImageBrush;
            var contentBody = GetTemplateChild(ButtonBaseConstants.ContentBodyName) as ContentControl;

            ButtonBaseHelper.ApplyTemplate(this, OpacityImageBrush, contentBody, Stretch, ImageSourceProperty);
        }
        private static void OnStretch(DependencyObject o, DependencyPropertyChangedEventArgs e)
        {
            var sender = o as ToggleButtonBase;

            if (sender == null)
            {
                return;
            }

            ButtonBaseHelper.OnStretch(e, sender.OpacityImageBrush);
        }
        private static void OnImageSource(DependencyObject o, DependencyPropertyChangedEventArgs e)
        {
            var sender = o as RoundButton;

            if (sender == null)
            {
                return;
            }

            ButtonBaseHelper.OnImageChange(e, sender.OpacityImageBrush);
        }