private static int CalculateHeightOfMiddlePartOfScrollBar(ICanHaveVerticalScrollBar parent, int bgHeight)
{
int midHeight;
if (parent.VerticalItemCount <= parent.VerticalMaxVisibleItems)
{
midHeight = bgHeight - (BarEndsHeight * 2);
}
else
{
midHeight = ((parent.VerticalMaxVisibleItems * bgHeight)
/ parent.VerticalItemCount)
- BarEndsHeight * 2;
}
if (midHeight >= bgHeight)
{
midHeight = bgHeight - (BarEndsHeight * 2);
}
else if (midHeight <= 0)
{
midHeight = 0;
}
return(midHeight);
}
public VerticalScrollBar(IWindow window, ICanHaveVerticalScrollBar parent, Border border)
: base(window, parent)
{
// scrollbars must be attached to a control
Window = window;
Parent = parent ?? throw new ArgumentNullException(nameof(parent));
_spriteSheet = Ui.SpriteSheet;
_border = border;
ZIndex = parent.ZIndex;
Visible = true;
_upArrow = new IconButtonUsingOverlay(window, this, Ui.ScrollBar.UpArrow,
Ui.ScrollBar.ArrowNormalOverlay, Ui.ScrollBar.ArrowPressedOverlay, Rectangle.Empty);
_upArrow.SetOnClick(ScrollUp);
_downArrow = new IconButtonUsingOverlay(window, this, Ui.ScrollBar.DownArrow,
Ui.ScrollBar.ArrowNormalOverlay, Ui.ScrollBar.ArrowPressedOverlay, Rectangle.Empty);
_downArrow.SetOnClick(ScrollDown);
_draggable = new Draggable(MouseButton.Left, 5);
_mouseScrollable = new MouseScrollable(parent, ModifierKeys.None);
_mouseScrollable.OnScroll = ScrollMouse;
}
