def validate_rectangle(rect):
if not rect:
raise errors.RectangleError("Missing rectangle")
rect = rect.split(",")
if len(rect) != 4:
raise errors.RectangleError("Invalid rectangle")
for a in rect:
if not Image._isint(a):
raise errors.RectangleError("Invalid rectangle")
elif int(a) < 0:
raise errors.RectangleError("Region out-of-bounds")
def region(self, rect):
""" Selects a sub-region of the image using the supplied rectangle,
x, y, width, height.
"""
box = (int(rect[0]), int(rect[1]), int(rect[0]) + int(rect[2]),
int(rect[1]) + int(rect[3]))
if box[2] > self.img.size[0] or box[3] > self.img.size[1]:
raise errors.RectangleError('Region out-of-bounds')
self.img = self.img.crop(box)
return self
