sign conventions for x,y, angle are weird

[GoogleCodeExporter]

Right now 'up' is negative-y, and clockwise is positive.  The convention for 
theta = 0 pointing to the right is theta is positive in counterclockwise. . 
.and having 'up' be negative y is pretty confusing for people.

What version of the product are you using? On what operating system?

HEAD, Ubuntu 9.10

Original issue reported on code.google.com by aresnick...@gmail.com on 20 Jun 2010 at 4:35

[GoogleCodeExporter]

I agree the angles are a bit strange. Up as negative is pretty standard for 
computer graphics. That and positive angles clockwise seems to be Qt showing 
through. So I think that is Ok.

I do think that 0 should probably be straight up, though. I will fix that.

I can also see having multiple modes available. Like for the polar examples, it 
would be cool to be able to say mode('polar') and have it do all of the angle 
and scaling transforms automatically.

Original comment by miss...@hotmail.com on 22 Jun 2010 at 12:22

[GoogleCodeExporter]

I think 0 to the right isn't necessarily confusing; I'm not sure "computer 
graphics" standard is the right lead to take?  Multiple modes would be nice (or 
if you could rotate the coordinate axes).  People have had a fine time 
adjusting to 0 to the right, negative up has been harder for them, for some 
reason.

Original comment by aresnick...@gmail.com on 22 Jun 2010 at 2:42

[GoogleCodeExporter]

If up is negative, than having 0 to the right and clockwise rotation actually 
makes trigonometry easier. Clockwise rotation messes with the sine function, 
but if up is negative, sign errors are automatically corrected.
If up is going to be 0, then using trig functions is something that one would 
have to think about more carefully no matter what the rotation convention or 
the sign convention on y.

Original comment by bundersc...@gmail.com on 22 Jun 2010 at 4:15

[GoogleCodeExporter]

If you try the latest source in mercurial, I have added a couple of different 
modes:

Logo: x+ right, y+ up, 0 angle up, +angles clockwise
Turtle: x+ right, y+ up, 0 angle right, +angles counter-cw

Any testing/feedback appreciated.

(Note that Pynguin requires Python 3 now!)

Original comment by miss...@hotmail.com on 22 Sep 2012 at 7:08

• Changed state: Started

[GoogleCodeExporter]

Multiple modes released in pynguin-0.13

Original comment by miss...@hotmail.com on 5 Apr 2013 at 5:12

• Changed state: Fixed