mirror of https://github.com/python/cpython
89 lines
2.0 KiB
Python
Executable File
89 lines
2.0 KiB
Python
Executable File
# Module 'rect'.
|
|
#
|
|
# Operations on rectangles.
|
|
# There is some normalization: all results return the object 'empty'
|
|
# if their result would contain no points.
|
|
|
|
|
|
# Exception.
|
|
#
|
|
error = 'rect.error'
|
|
|
|
|
|
# The empty rectangle.
|
|
#
|
|
empty = (0, 0), (0, 0)
|
|
|
|
|
|
# Check if a rectangle is empty.
|
|
#
|
|
def is_empty((left, top), (right, bottom)):
|
|
return left >= right or top >= bottom
|
|
|
|
|
|
# Compute the intersection or two or more rectangles.
|
|
# This works with a list or tuple argument.
|
|
#
|
|
def intersect(list):
|
|
if not list: raise error, 'intersect called with empty list'
|
|
if is_empty(list[0]): return empty
|
|
(left, top), (right, bottom) = list[0]
|
|
for rect in list[1:]:
|
|
if is_empty(rect):
|
|
return empty
|
|
(l, t), (r, b) = rect
|
|
if left < l: left = l
|
|
if top < t: top = t
|
|
if right > r: right = r
|
|
if bottom > b: bottom = b
|
|
if is_empty((left, top), (right, bottom)):
|
|
return empty
|
|
return (left, top), (right, bottom)
|
|
|
|
|
|
# Compute the smallest rectangle containing all given rectangles.
|
|
# This works with a list or tuple argument.
|
|
#
|
|
def union(list):
|
|
(left, top), (right, bottom) = empty
|
|
for (l, t), (r, b) in list[1:]:
|
|
if not is_empty((l, t), (r, b)):
|
|
if l < left: left = l
|
|
if t < top: top = t
|
|
if r > right: right = r
|
|
if b > bottom: bottom = b
|
|
res = (left, top), (right, bottom)
|
|
if is_empty(res):
|
|
return empty
|
|
return res
|
|
|
|
|
|
# Check if a point is in a rectangle.
|
|
#
|
|
def pointinrect((h, v), ((left, top), (right, bottom))):
|
|
return left <= h < right and top <= v < bottom
|
|
|
|
|
|
# Return a rectangle that is dh, dv inside another
|
|
#
|
|
def inset(((left, top), (right, bottom)), (dh, dv)):
|
|
left = left + dh
|
|
top = top + dv
|
|
right = right - dh
|
|
bottom = bottom - dv
|
|
r = (left, top), (right, bottom)
|
|
if is_empty(r):
|
|
return empty
|
|
else:
|
|
return r
|
|
|
|
|
|
# Conversions between rectangles and 'geometry tuples',
|
|
# given as origin (h, v) and dimensions (width, height).
|
|
#
|
|
def rect2geom((left, top), (right, bottom)):
|
|
return (left, top), (right-left, bottom-top)
|
|
|
|
def geom2rect((h, v), (width, height)):
|
|
return (h, v), (h+width, v+height)
|