public void Construction()
{
const float degrees = 30;
RotationMatrix r = new RotationMatrix(30);
Assert.AreEqual(degrees, r.Angle);
Assert.AreEqual(4, r.Count, "RotationMatrix should have 4 entries");
Assert.AreEqual(2, r.RowCount, "RotationMatrix should have 2 rows");
Assert.AreEqual(2, r.ColumnCount, "RotationMatrix should have 2 columns");
float radians = ExtensionMethods.ToRadians(degrees);
float[] expectedValues = {
(float)Math.Cos(radians),
-(float)Math.Sin(radians),
(float)Math.Sin(radians),
(float)Math.Cos(radians)
};
for (int i = 0; i < expectedValues.Length; ++i) {
Assert.AreEqual(expectedValues[i], r[i], "Value {0} is incorrect", i);
}
}
public static PointF Rotate(this PointF p, float angle)
{
RotationMatrix r = new RotationMatrix(angle);
float x = r[0] * p.X + r[1] * p.Y;
float y = r[2] * p.X + r[3] * p.Y;
return new PointF(x, y);
}