/// <summary>
/// Creates a matrix that rotates about a specified center.
/// </summary>
/// <param name="angle">Angle of rotation in radians.</param>
/// <param name="center">The center of the rotation.</param>
/// <returns>The created rotation matrix.</returns>
public static Matrix Rotation(double angle, Vector center)
{
return
Matrix.CreateTranslation(-center)
* Matrix.CreateRotation(angle)
* Matrix.CreateTranslation(center);
}
/// <summary>
/// Gets the root of the control's visual tree and the position of the control
/// in the root's coordinate space.
/// </summary>
/// <param name="v">The visual.</param>
/// <returns>A tuple containing the root and the position of the control.</returns>
private static Tuple<IRenderRoot, Vector> GetRootAndPosition(IVisual v)
{
var result = new Vector();
while (!(v is IRenderRoot))
{
result = new Vector(result.X + v.Bounds.X, result.Y + v.Bounds.Y);
v = v.VisualParent;
if (v == null)
{
throw new InvalidOperationException("Control is not attached to visual tree.");
}
}
return Tuple.Create((IRenderRoot)v, result);
}
/// <summary>
/// Gets the visual offset from the specified ancestor.
/// </summary>
/// <param name="ancestor">The ancestor visual.</param>
/// <param name="visual">The visual.</param>
/// <returns>The visual offset.</returns>
private static Vector GetOffsetFrom(IVisual ancestor, IVisual visual)
{
var result = new Vector();
while (visual != ancestor)
{
result = new Vector(result.X + visual.Bounds.X, result.Y + visual.Bounds.Y);
visual = visual.VisualParent;
if (visual == null)
{
throw new ArgumentException("'visual' is not a descendent of 'ancestor'.");
}
}
return result;
}
public static Matrix Translation(Vector v)
{
return Translation(v.X, v.Y);
}
public static Matrix Scaling(Vector scale)
{
return new Matrix(scale.X, 0, 0, scale.Y, 0, 0);
}
/// <summary>
/// Translates the rectangle by an offset.
/// </summary>
/// <param name="offset">The offset.</param>
/// <returns>The translated rectangle.</returns>
public Rect Translate(Vector offset)
{
return new Rect(Position + offset, Size);
}
/// <summary>
/// Creates a translation matrix from the given vector.
/// </summary>
/// <param name="position">The translation position.</param>
/// <returns>A translation matrix.</returns>
public static Matrix CreateTranslation(Vector position)
{
return CreateTranslation(position.X, position.Y);
}
/// <summary>
/// Creates a scale matrix from the given vector scale.
/// </summary>
/// <param name="scales">The scale to use.</param>
/// <returns>A scaling matrix.</returns>
public static Matrix CreateScale(Vector scales)
{
return new Matrix(scales.X, 0, 0, scales.Y, 0, 0);
}
