/// <summary>
/// Positions one rectangle relative to another, according to the specified <see cref="PopupAlignmentPoint"/> values.
/// </summary>
/// <param name="actualTargetElement">The element that was actually targeted for placement of the popup.</param>
/// <param name="targetOrigin">The origin point of the target rectangle.</param>
/// <param name="target">The target rectangle.</param>
/// <param name="popupOrigin">The origin point of the popup rectangle.</param>
/// <param name="popup">The popup size.</param>
/// <returns>The popup rectangle positioned relative to the target rectangle and including the
/// values of <see cref="HorizontalOffset"/> and <see cref="VerticalOffset"/> properties.</returns>
private RectangleD PositionRects(UIElement actualTargetElement, PopupAlignmentPoint targetOrigin, RectangleD target, PopupAlignmentPoint popupOrigin, Size2D popup)
{
var transformOriginX = 0.0;
switch (popupOrigin)
{
case PopupAlignmentPoint.TopCenter:
case PopupAlignmentPoint.Center:
case PopupAlignmentPoint.BottomCenter:
transformOriginX = popup.Width / 2.0;
break;
case PopupAlignmentPoint.TopRight:
case PopupAlignmentPoint.MiddleRight:
case PopupAlignmentPoint.BottomRight:
transformOriginX = popup.Width;
break;
}
var transformOriginY = 0.0;
switch (popupOrigin)
{
case PopupAlignmentPoint.MiddleLeft:
case PopupAlignmentPoint.Center:
case PopupAlignmentPoint.MiddleRight:
transformOriginY = popup.Height / 2.0;
break;
case PopupAlignmentPoint.BottomLeft:
case PopupAlignmentPoint.BottomCenter:
case PopupAlignmentPoint.BottomRight:
transformOriginY = popup.Height;
break;
}
var resultX = 0.0;
var resultY = 0.0;
switch (targetOrigin)
{
case PopupAlignmentPoint.TopLeft:
resultX = target.Left;
resultY = target.Top;
break;
case PopupAlignmentPoint.TopCenter:
resultX = target.Left + (target.Width / 2.0);
resultY = target.Top;
break;
case PopupAlignmentPoint.TopRight:
resultX = target.Right;
resultY = target.Top;
break;
case PopupAlignmentPoint.MiddleLeft:
resultX = target.Left;
resultY = target.Top + (target.Height / 2.0);
break;
case PopupAlignmentPoint.Center:
resultX = target.Left + (target.Width / 2.0);
resultY = target.Top + (target.Height / 2.0);
break;
case PopupAlignmentPoint.MiddleRight:
resultX = target.Right;
resultY = target.Top + (target.Height / 2.0);
break;
case PopupAlignmentPoint.BottomLeft:
resultX = target.Left;
resultY = target.Bottom;
break;
case PopupAlignmentPoint.BottomCenter:
resultX = target.Left + (target.Width / 2.0);
resultY = target.Bottom;
break;
case PopupAlignmentPoint.BottomRight:
resultX = target.Right;
resultY = target.Bottom;
break;
}
popupTransformOrigin = new Point2D(transformOriginX, transformOriginY);
if (actualTargetElement != null)
{
var actualTargetTransform = actualTargetElement.GetTransformToViewMatrix();
var actualTargetPosition = new Point2D(HorizontalOffset + resultX, VerticalOffset + resultY);
Point2D.Transform(ref actualTargetPosition, ref actualTargetTransform, out popupPosition);
}
else
{
popupPosition = new Point2D(
PlacementRectangle.X + HorizontalOffset + resultX,
PlacementRectangle.Y + VerticalOffset + resultY);
}
ComputeTransformationMatrices();
return new RectangleD(-transformOriginX, -transformOriginY, popup.Width, popup.Height);
}