/// <summary>
/// Gets the bounding box of a rectangle rotated at a specified angle.
/// </summary>
/// <param name="rectangle">The rectangle to rotate.</param>
/// <param name="angleInRadians">The angle of rotation (measured in radians).</param>
/// <returns>The bounding box of the rotated rectangle.</returns>
/// <remarks>The width and height of the bounding box are calculated using the following formulae:
/// w' = w * abs(cos( alpha )) + h * abs(sin( alpha ))
/// h' = h * abs(cos( alpha )) + w * abs(sin( alpha )),
/// where w and h are the width and height of the rectangle and alpha - the angle of rotation.
/// </remarks>
/// <seealso cref="http://unlogic.co.uk/posts/bounding-box-of-rotated-image.html"/>
public static Rectangle GetBoundingBoxAfterRotation(Rectangle rectangle, double angleInRadians)
{
double width = (rectangle.Width * Math.Abs(Math.Cos(angleInRadians))) +
(rectangle.Height * Math.Abs(Math.Sin(angleInRadians)));
double height = (rectangle.Height * Math.Abs(Math.Cos(angleInRadians))) +
(rectangle.Width * Math.Abs(Math.Sin(angleInRadians)));
return new Rectangle(width, height);
}
/// <summary>
/// The entry point of the program.
/// </summary>
private static void Main()
{
Point point = new Point(1, 0);
double theta = Math.PI / 2;
Point pointRotated = AffineTransformer.RotatePoint(point, theta);
Console.WriteLine(pointRotated);
Rectangle rectangle = new Rectangle(20, 10);
Rectangle boundingBox = AffineTransformer.GetBoundingBoxAfterRotation(rectangle, theta / 3);
Console.WriteLine(boundingBox);
}
