private static bool ValidateRectangle(Rect rectangleA)
{
if(rectangleA.Width < 1 || rectangleA.Height < 1)
{
return false;
}
return true;
}
/// <summary>
/// Checks for containment relationship between two rectangles.
/// </summary>
/// <param name="rectangleA"></param>
/// <param name="rectangleB"></param>
/// <returns> Returns true if RectangleA entirely contains RectangleB or
/// if RectangleB entirely contains RectangleA</returns>
public static bool CheckContainment(Rect rectangleA, Rect rectangleB)
{
if (!ValidateRectangle(rectangleA) || !ValidateRectangle(rectangleB))
{
return false;
}
bool outside = false;
// look for an edge in the (potentially) smaller rectangle outside the bigger rectangle
if (rectangleA.Width > rectangleB.Width)
{
outside = ((rectangleB.Left < rectangleA.Left) ||
(rectangleB.Right > rectangleA.Right) ||
(rectangleB.Top > rectangleA.Top) ||
(rectangleB.Bottom < rectangleA.Bottom));
}
else
{
outside = ((rectangleA.Left < rectangleB.Left) ||
(rectangleA.Right > rectangleB.Right) ||
(rectangleA.Top > rectangleB.Top) ||
(rectangleA.Bottom < rectangleB.Bottom));
}
return !outside;
}
/// <summary>
/// Checks whether two rectangles intersect by finding out the intersection points.
/// </summary>
/// <param name="rectangleA"></param>
/// <param name="rectangleB"></param>
/// <returns>True if rectangles intersect else false</returns>
public static bool CheckIntersection(Rect rectangleA, Rect rectangleB, out ArrayList InterSectingPoints)
{
InterSectingPoints = new ArrayList();
if (!ValidateRectangle(rectangleA) || !ValidateRectangle(rectangleB))
{
return false;
}
if (rectangleA.Left > rectangleB.Left && rectangleA.Left < rectangleB.Right)
{
// Left side of rectangle A lies in between rectangle B edges.
// Check if it intersects
if (rectangleB.Top < rectangleA.Top && rectangleB.Top > rectangleA.Bottom)
{
Point pointIntersection = new Point(rectangleA.Left, rectangleB.Top);
InterSectingPoints.Add(pointIntersection);
}
if (rectangleB.Bottom < rectangleA.Top && rectangleB.Bottom > rectangleA.Bottom)
{
Point pointIntersection = new Point(rectangleA.Left, rectangleB.Bottom);
InterSectingPoints.Add(pointIntersection);
}
}
if (rectangleA.Right > rectangleB.Left && rectangleA.Right < rectangleB.Right)
{
// Right side of rectangle A lies in between rectangle B edges.
// Check if it intersects
if (rectangleB.Top < rectangleA.Top && rectangleB.Top > rectangleA.Bottom)
{
Point pointIntersection = new Point(rectangleA.Right, rectangleB.Top);
InterSectingPoints.Add(pointIntersection);
}
if (rectangleB.Bottom < rectangleA.Top && rectangleB.Bottom > rectangleA.Bottom)
{
Point pointIntersection = new Point(rectangleA.Right, rectangleB.Bottom);
InterSectingPoints.Add(pointIntersection);
}
}
if (rectangleA.Top > rectangleB.Bottom && rectangleA.Top < rectangleB.Top)
{
// Top side of rectangle A lies in between rectangle B Top and Bottom.
// Check if it intersects
if (rectangleB.Left < rectangleA.Right && rectangleB.Left > rectangleA.Left)
{
Point pointIntersection = new Point(rectangleB.Left, rectangleA.Top);
InterSectingPoints.Add(pointIntersection);
}
if (rectangleB.Right < rectangleA.Right && rectangleB.Right > rectangleA.Left)
{
Point pointIntersection = new Point(rectangleB.Right, rectangleA.Top);
InterSectingPoints.Add(pointIntersection);
}
}
if (rectangleA.Bottom > rectangleB.Bottom && rectangleA.Bottom < rectangleB.Top)
{
// Top side of rectangle A lies in between rectangle B Top and Bottom.
// Check if it intersects
if (rectangleB.Left < rectangleA.Right && rectangleB.Left > rectangleA.Left)
{
Point pointIntersection = new Point(rectangleB.Left, rectangleA.Bottom);
InterSectingPoints.Add(pointIntersection);
}
if (rectangleB.Right < rectangleA.Right && rectangleB.Right > rectangleA.Left)
{
Point pointIntersection = new Point(rectangleB.Right, rectangleA.Bottom);
InterSectingPoints.Add(pointIntersection);
}
}
return (InterSectingPoints.Count > 0);
}
/// <summary>
/// Checks if two rectangles have adjacent edges
/// </summary>
/// <param name="rectangleA"></param>
/// <param name="rectangleB"></param>
/// <returns>True if there is adjacency</returns>
public static bool CheckAdjacent(Rect rectangleA, Rect rectangleB)
{
if(!ValidateRectangle(rectangleA) || !ValidateRectangle(rectangleB))
{
return false;
}
bool adjacent = false;
if (rectangleA.Left == rectangleB.Right ||
rectangleA.Right == rectangleB.Left ||
rectangleA.Left == rectangleB.Left ||
rectangleA.Right == rectangleB.Right)
{
// Now that we have a common side check if it is proper or sub-line
if (rectangleA.Top >= rectangleB.Top)
{
adjacent = (rectangleB.Bottom >= rectangleA.Bottom);
}
if (!adjacent && rectangleB.Top >= rectangleA.Top)
{
adjacent = (rectangleA.Bottom >= rectangleB.Bottom);
}
}
if (rectangleA.Top == rectangleB.Bottom ||
rectangleA.Bottom == rectangleB.Top ||
rectangleA.Top == rectangleB.Top ||
rectangleA.Bottom == rectangleB.Bottom)
{
if (rectangleA.Right >= rectangleB.Right)
{
adjacent = (rectangleB.Left >= rectangleA.Left);
}
if (!adjacent && rectangleB.Right >= rectangleA.Right)
{
adjacent = (rectangleA.Left >= rectangleB.Left);
}
}
return adjacent;
}