[PYTHON IMAGE-SIG] docs for ImagePath? (and a bug)
Fri, 09 May 1997 16:00:42 +1000
I've been reading the source for path.c to try to figure out the ImagePath
module. As far as I can tell, ImagePath does the following. Can someone
(Hi Fredrik!) confirm or deny these bits?
Returns a Path object. This behaves like a sequence of x,y tuples, and
can be passed to ImageDraw.Draw methods and the like. Actually, no, it
doesn't. It supports the len and getitem methods, but everything else
is a null pointer, and causes Python to seg fault if called.
BUG This is a bug - if you're going to pretend to be a sequence, you should
support all methods of the sequence. (even if you just raise a TypeError)
It can be passed a sequence of (x,y) tuples, a sequence of numbers
(which are interpreted as (x0,y0,x1,y1,x2,y2,....), or another Path
Path objects have the following methods:
Simple-minded method to shorten path. A point is removed if
the city block distance to the previous point is less than the
given distance. "city block distance"? dist defaults to '2.0'
return the bounding box of all points in the path.
apply function fn to each (x,y) element of the path. fn will be called
as fn(x,y). Don't try the real funky map() tricks - it's not really the
same as map(). :)
(why doesn't it have filter and reduce?)
return the path as a list of xy tuples.
perform an affine transform on each point in the path.
(x,y) = (a*x+b*y+c, d*x+e*y+f)
if wrap is passed as an arg, wrap y coordinate points at 'wrap'.
IMAGE-SIG - SIG on Image Processing with Python
send messages to: firstname.lastname@example.org
administrivia to: email@example.com