private void PositionItem(ILayoutable item, HorizontalPosition horizontalPosition, VerticalPosition verticalPosition, LayoutOrigin layoutFrom)
{
// Make sure this is still the item's parent
if (item.Parent != _backgroundSprite)
{
if (_items.ContainsKey(item))
{
_items.Remove(item);
}
return;
}
// Position the item correctly
float posX;
float posY;
// Figure out starting horizontal and vertical coordinates
if (horizontalPosition.Alignment == HorizontalPosition.PositionAlignment.Left)
{
posX = 0 - ScaleX;
}
else if (horizontalPosition.Alignment == HorizontalPosition.PositionAlignment.Right)
{
posX = ScaleX;
}
else
{
posX = 0;
}
if (verticalPosition.Alignment == VerticalPosition.PositionAlignment.Top)
{
posY = ScaleY;
}
else if (verticalPosition.Alignment == VerticalPosition.PositionAlignment.Bottom)
{
posY = 0 - ScaleY;
}
else
{
posY = 0;
}
// Calculate offsets
if (horizontalPosition.OffsetIsPercentage)
{
var total = ScaleX * 2;
posX += (horizontalPosition.Offset * total);
}
else
{
posX += horizontalPosition.Offset;
}
if (verticalPosition.OffsetIsPercentage)
{
var total = ScaleY * 2;
posY += (verticalPosition.Offset * total);
}
else
{
posY += verticalPosition.Offset;
}
// Adjust for the specified layout origin
switch (layoutFrom)
{
case LayoutOrigin.TopLeft:
{
posX += item.ScaleX;
posY -= item.ScaleY;
break;
}
case LayoutOrigin.TopRight:
{
posX -= item.ScaleX;
posY -= item.ScaleY;
break;
}
case LayoutOrigin.BottomLeft:
{
posX += item.ScaleX;
posY += item.ScaleY;
break;
}
case LayoutOrigin.BottomRight:
{
posX -= item.ScaleX;
posY += item.ScaleY;
break;
}
case LayoutOrigin.BottomCenter:
{
posY += item.ScaleY;
break;
}
case LayoutOrigin.TopCenter:
{
posY -= item.ScaleY;
break;
}
case LayoutOrigin.Center:
default:
{
// PosX and PosY remain at center
break;
}
}
// Set the item's position to the calculated spot
item.RelativeX = posX;
item.RelativeY = posY;
}
public void AddItem(ILayoutable item, HorizontalPosition horizontalPosition, VerticalPosition verticalPosition, LayoutOrigin layoutFrom = LayoutOrigin.Center)
{
if (item == null)
{
throw new ArgumentNullException("item");
}
var position = new OverallPosition
{
HorizontalPosition = horizontalPosition,
VerticalPosition = verticalPosition,
LayoutOrigin = layoutFrom
};
_items.Add(item, position);
item.Alpha = _alpha;
item.AttachTo(_backgroundSprite, true);
item.RelativeZ = 0.1f;
item.ParentLayout = this;
if (item.OnAddedToLayout != null)
{
item.OnAddedToLayout(this);
}
PositionItem(item, horizontalPosition, verticalPosition, layoutFrom);
// When the size changes, make sure to reposition the item so it's still in the same spot
item.OnSizeChangeHandler = new LayoutableEvent(delegate(ILayoutable sender) { PositionItem(item, horizontalPosition, verticalPosition, layoutFrom); });
}
