def rotate(self,
degrees,
clockwise=False,
resample_algorithm=nearest,
resize_canvas=True):
"""
Returns the image obtained by rotating this image by the
given number of degrees.
Anticlockwise unless clockwise=True is given.
"""
# translate to the origin first, then rotate, then translate back
transform = AffineTransform()
transform = transform.translate(self.width * -0.5, self.height * -0.5)
transform = transform.rotate(degrees, clockwise=clockwise)
width, height = self.width, self.height
if resize_canvas:
# determine new width
width, height = get_transformed_dimensions(transform,
(0, 0, width, height))
transform = transform.translate(width * 0.5, height * 0.5)
pixels = resample_algorithm.affine(self,
transform,
resize_canvas=resize_canvas)
return self._copy(pixels)
def test_inverse(self):
# identity inverse
self.assertEqual(AffineTransform().inverse(), AffineTransform())
self.assertEqual(
AffineTransform((2, 0, 0, 0, 2, 0, 0, 0, 2)).inverse(),
AffineTransform((0.5, 0, 0, 0, 0.5, 0, 0, 0, 0.5)))
# inverted A*0 = A/0, which is an error
self.assertRaises(ValueError, (AffineTransform() * 0).inverse)
def test_constructor_3x3tuple(self):
a = AffineTransform(((1, 2, 3), (4, 5, 6), (7, 8, 9)))
self.assertEqual(a.matrix, (1, 2, 3, 4, 5, 6, 7, 8, 9))
self.assertRaises(ValueError, AffineTransform, ((1, 2, 3), (4, 5, 6)))
self.assertRaises(ValueError, AffineTransform,
((1, 2), (3, 4), (5, 6)))
def test_rotate(self):
a = AffineTransform()
self.assertEqual(a.rotate(0), a)
self.assertEqual(a.rotate(360), a)
self.assertEqual(a.rotate(90), a.rotate(270, clockwise=True))
self.assertEqual(a.rotate(90),
AffineTransform((0, -1, 0, 1, 0, 0, 0, 0, 1)))
def test_mult_vector(self):
a = AffineTransform() * 2
self.assertEqual(a * (1, 2), (2, 4))
self.assertEqual(a * (1, 2, 3), (2, 4, 6))
self.assertRaises(ValueError, lambda: a * (1, ))
self.assertRaises(ValueError, lambda: a * (1, 2, 3, 4))
self.assertRaises(ValueError, lambda: a * (1, 2, 3, 4))
self.assertRaises(TypeError, lambda: (1, 2, 3) * a)
def rotate(self, degrees, clockwise=False, resample_algorithm=nearest, resize_canvas=True):
"""
Returns the image obtained by rotating this image by the
given number of degrees.
Anticlockwise unless clockwise=True is given.
"""
# translate to the origin first, then rotate, then translate back
transform = AffineTransform()
transform = transform.translate(self.width * -0.5, self.height * -0.5)
transform = transform.rotate(degrees, clockwise=clockwise)
width, height = self.width, self.height
if resize_canvas:
# determine new width
width, height = get_transformed_dimensions(transform, (0, 0, width, height))
transform = transform.translate(width * 0.5, height * 0.5)
pixels = resample_algorithm.affine(self, transform, resize_canvas=resize_canvas)
return self._copy(pixels)
def test_rotate(self):
a = AffineTransform()
self.assertEqual(a.rotate(0), a)
self.assertEqual(a.rotate(360), a)
self.assertEqual(a.rotate(90), a.rotate(270, clockwise=True))
self.assertEqual(a.rotate(90), AffineTransform((0, -1, 0, 1, 0, 0, 0, 0, 1)))
def test_mult_scalar(self):
a = AffineTransform() * 2
self.assertEqual(a.matrix, (2, 0, 0, 0, 2, 0, 0, 0, 2))
a = AffineTransform() * -1
self.assertEqual(a.matrix, (-1, 0, 0, 0, -1, 0, 0, 0, -1))
def test_translate(self):
a = AffineTransform()
t = a.translate(3, 4)
self.assertEqual(t.matrix, (1, 0, 0, 0, 1, 0, 3, 4, 1))
self.assertEqual(t.translate(3, 4).matrix, (1, 0, 0, 0, 1, 0, 6, 8, 1))
def test_constructor_identity(self):
a = AffineTransform()
self.assertEqual(a.matrix, (1, 0, 0, 0, 1, 0, 0, 0, 1))
def test_chained_translate_rotate(self):
a = AffineTransform()
# translate by (3, 4). rotate by 90 degrees
t = a.translate(3, 4).rotate(90)
self.assertEqual(t.matrix, (0, -1, 0, 1, 0, 0, 4, -3, 1))
def test_div_affine(self):
a = AffineTransform() * 8
b = AffineTransform() * 2
self.assertEqual((a / b).matrix, (4, 0, 0, 0, 4, 0, 0, 0, 4))
def test_mult_affine(self):
a = AffineTransform() * 2
b = AffineTransform() * 3
self.assertEqual((a * b).matrix, (6, 0, 0, 0, 6, 0, 0, 0, 6))
def test_chained_translate_rotate_translate(self):
a = AffineTransform()
# translate by (3, 4). rotate by 90 degrees. then translate back.
t = a.translate(3, 4).rotate(90).translate(-3, -4)
self.assertEqual(t.matrix, (0, -1, 0, 1, 0, 0, 1, -7, 1))
def test_chained_translate_rotate(self):
a = AffineTransform()
# translate by (3, 4). rotate by 90 degrees
t = a.translate(3, 4).rotate(90)
self.assertEqual(t.matrix, (0, -1, 0, 1, 0, 0, 4, -3, 1))
def test_chained_translate_rotate_translate(self):
a = AffineTransform()
# translate by (3, 4). rotate by 90 degrees. then translate back.
t = a.translate(3, 4).rotate(90).translate(-3, -4)
self.assertEqual(t.matrix, (0, -1, 0, 1, 0, 0, 1, -7, 1))
def test_constructor_9tuple(self):
a = AffineTransform((1, 2, 3, 4, 5, 6, 7, 8, 9))
self.assertEqual(a.matrix, (1, 2, 3, 4, 5, 6, 7, 8, 9))
self.assertRaises(ValueError, AffineTransform,
(1, 2, 3, 4, 5, 6, 7, 8))
def test_rmult_scalar(self):
a = 2 * AffineTransform()
self.assertEqual(a.matrix, (2, 0, 0, 0, 2, 0, 0, 0, 2))
a = -1 * AffineTransform()
self.assertEqual(a.matrix, (-1, 0, 0, 0, -1, 0, 0, 0, -1))
def test_div_scalar(self):
a = AffineTransform() / 2
self.assertEqual(a.matrix, (0.5, 0, 0, 0, 0.5, 0, 0, 0, 0.5))
def resize(self, source, width, height, resize_canvas=True):
transform = AffineTransform().scale(
width / float(source.width),
height / float(source.height)
)
return self.affine(source, transform, resize_canvas=resize_canvas)
def test_translate(self):
a = AffineTransform()
t = a.translate(3, 4)
self.assertEqual(t.matrix, (1, 0, 0, 0, 1, 0, 3, 4, 1))
self.assertEqual(t.translate(3, 4).matrix, (1, 0, 0, 0, 1, 0, 6, 8, 1))
