def test_crop(self):
context = ImageTransform((640, 480))
cropped = context.crop(Rect(200, 100, 300, 200))
vector = Vector(250, 150)
transformed = cropped.transform_vector(vector)
self.assertEqual(transformed, Vector(50, 50))
untransformed = cropped.untransform_vector(transformed)
self.assertEqual(untransformed, vector)
def test_resize(self):
context = ImageTransform((640, 480))
resized = context.resize((320, 240))
vector = Vector(100, 200)
transformed = resized.transform_vector(vector)
self.assertEqual(transformed, Vector(50, 100))
untransformed = resized.untransform_vector(transformed)
self.assertEqual(untransformed, vector)
def test_resize_then_crop(self):
context = ImageTransform((640, 480))
resized = context.resize((320, 240))
cropped = resized.crop(Rect(200, 100, 300, 200))
vector = Vector(500, 300)
transformed = cropped.transform_vector(vector)
self.assertEqual(transformed, Vector(50, 50))
untransformed = cropped.untransform_vector(transformed)
self.assertEqual(untransformed, vector)
def untransform_vector(self, vector):
"""
Transforms the given vector back to the coordinate space of the source image.
This performs the inverse of `transform_vector`. Use this to find where a point
in the final cropped/resized image originated from in the source image.
Returns a new vector.
"""
return Vector(vector.x / self.scale[0] - self.offset[0],
vector.y / self.scale[1] - self.offset[1])
def transform_vector(self, vector):
"""
Transforms the given vector into the coordinate space of the final image.
Use this to find out where a point on the source image would end up in the
final image after cropping/resizing has been performed.
Returns a new vector.
"""
return Vector((vector.x + self.offset[0]) * self.scale[0],
(vector.y + self.offset[1]) * self.scale[1])
def test_set_centroid_with_vector(self):
rect = Rect(100, 150, 200, 350)
rect.centroid = Vector(500, 500)
self.assertEqual(rect, (450, 400, 550, 600))
def test_set_size_with_vector(self):
rect = Rect(100, 150, 200, 350)
rect.size = Vector(200, 400)
self.assertEqual(rect, (50, 50, 250, 450))
