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[pygame] draw.arc comment
Hi,
As you may have been able to tell, I've been working with draw.arc recently...
One problem that i have is that it has its 0 degree mark on the right hand side, 90 on the top, 180 on the left, and 270 on the bottom. This is problematic because as (0, 0) is the top left hand corner and the points increase to the bottom corner, draw.arc is 90 degrees out of phase with any trig calculations one does - with zero on the bottom, etc, viz:
=== BEGIN
import math
def get_sides(pt1, pt2):
x1, y1 = pt1
x2, y2 = pt2
return (x2 - x1), (y2 - y1) # opplen, adjlen
def pts_to_angle(pt1, pt2):
opplen, adjlen = get_sides(pt1, pt2)
angle = math.degrees(math.atan2(opplen, adjlen))
if angle < 0:
angle += 360
return angle
=== END
Of course draw.arc _can_ be wrapped - but any user who needs to do dynamic calculations will have to do so. Whether or not it would be reasonable to change it at this stage is another matter (If indeed, it is agreed that it is a problem).
-T. (It's not that I'm not hugely grateful for draw.arc - believe me, i am ;-)
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