Relative Calculation

Margin.cs

	public struct Margin {
		public int? Left;
		public int? Right;
		public int? Top;
		public int? Bottom;

		public Margin ( int? side ) {
			Left = side;
			Right = side;
			Top = side;
			Bottom = side;
		}
		public Margin ( int? height, int? width ) {
			Left = width;
			Right = width;
			Top = height;
			Bottom = height;
		}
		public Margin ( int? left, int? right, int? top, int? bottom ) {
			Left = left;
			Right = right;
			Top = top;
			Bottom = bottom;
		}
	}

Original.vb

	Private Function getRelativePosition(ByVal left As Integer, ByVal right As Integer, ByVal top As Integer, ByVal bottom As Integer, ByVal height As Integer, ByVal width As Integer) As Point
		Dim ret As Point
		If left <> -1 Then
			ret.X = left
		Else
			If right <> -1 Then
				ret.X = clipRectangle.Width - (right + width)
			Else
				ret.X = 0
			End If
		End If
		If top <> -1 Then
			ret.Y = top
		Else
			If bottom <> -1 Then
				ret.Y = clipRectangle.Height - (bottom + height)
			Else
				ret.Y = 0
			End If
		End If
		Return ret
	End Function
	Private Function getRelativeSize(ByVal left As Integer, ByVal right As Integer, ByVal top As Integer, ByVal bottom As Integer, ByVal height As Integer, ByVal width As Integer) As Size
		Dim ret As Size
		If right <> -1 Then
			If left <> -1 Then
				ret.Width = clipRectangle.Width - (left + right)
			Else
				ret.Width = width
			End If
		Else
			ret.Width = width
		End If
		If bottom <> -1 Then
			If top <> -1 Then
				ret.Height = clipRectangle.Height - (top + bottom)
			Else
				ret.Height = height
			End If
		Else
			ret.Height = height
		End If
		Return ret
	End Function
	Private Function getRelativeRectangle(ByVal left As Integer, ByVal right As Integer, ByVal top As Integer, ByVal bottom As Integer, ByVal height As Integer, ByVal width As Integer) As Rectangle
		Return New Rectangle(getRelativePosition(left, right, top, bottom, height, width), getRelativeSize(left, right, top, bottom, height, width))
	End Function

UiConversion.cs

	public static class UiConversion {
		public static Vector2 RelativePosition ( int? width, int? height, Margin margin, Viewport viewport ) {
			Vector2 retPos = new Vector2();

			if ( margin.Left.HasValue )
				retPos.X = margin.Left.Value;
			else
				if ( margin.Right.HasValue && width.HasValue )
					retPos.X = viewport.Width - ( margin.Right.Value + width.Value );
				else
					retPos.X = 0;

			if ( margin.Top.HasValue )
				retPos.Y = margin.Top.Value;
			else
				if ( margin.Bottom.HasValue && height.HasValue )
					retPos.Y = viewport.Height - ( margin.Bottom.Value + height.Value );
				else
					retPos.Y = 0;

			return retPos;
		}

		public static Vector2 RelativeSize ( int? width, int? height, Margin margin, Viewport viewport ) {
			Vector2 retVect = new Vector2();

			if ( margin.Right.HasValue ) {
				if ( margin.Left.HasValue ) {
					retVect.X = viewport.Width - ( margin.Right.Value + margin.Left.Value );
				} else {
					if ( width.HasValue ) {
						retVect.X = width.Value;
					} else {
						retVect.X = 0;
					}
				}
			} else {
				if ( width.HasValue ) {
					retVect.X = width.Value;
				} else {
					retVect.X = 0;
				}
			}

			if ( margin.Bottom.HasValue ) {
				if ( margin.Top.HasValue ) {
					retVect.Y = viewport.Height - ( margin.Bottom.Value + margin.Top.Value );
				} else {
					if ( height.HasValue ) {
						retVect.Y = height.Value;
					} else {
						retVect.Y = 0;
					}
				}
			} else {
				if ( height.HasValue ) {
					retVect.Y = height.Value;
				} else {
					retVect.Y = 0;
				}
			}

			return retVect;
		}
		
		public static Rectangle RelativeRectangle ( int? width, int? height, Margin margin, Viewport viewport ) {
			Vector2 pos = RelativePosition( width, height, margin, viewport );
			Vector2 size = RelativeSize( width, height, margin, viewport );
			return new Rectangle( (int) pos.X, (int) pos.Y, (int) size.X, (int) size.Y );
		}
	}