[PATCH 04/20] dix: fix comment, directions flagged are 45°

Peter Hutterer peter.hutterer at who-t.net
Wed Apr 20 20:47:15 PDT 2011


On Wed, Apr 20, 2011 at 11:02:49PM +0200, Simon Thum wrote:
> On 04/20/2011 08:28 AM, Peter Hutterer wrote:
> > The two directions returned by this calculation are always the two boundary
> > conditions. Since we don't do quadrants but octants, the flagged ones are
> > 45°, not 90°. e.g. an angle of 35° flags E and NE.
> > 
> Yes, so 2 flagged directions cover an angle of 90 degrees. I agree the
> wording can be improved, but I'd rather do "45 degree each" or something
> like it.

amended to spell "45 degrees each", thanks.

Cheers,
  Peter
 
> Cheers,
> 
> Simon
> 
> > Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
> > ---
> >  dix/ptrveloc.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> > 
> > diff --git a/dix/ptrveloc.c b/dix/ptrveloc.c
> > index e95ccbe..50ad22a 100644
> > --- a/dix/ptrveloc.c
> > +++ b/dix/ptrveloc.c
> > @@ -486,7 +486,7 @@ DoGetDirection(int dx, int dy){
> >      /* find direction. We avoid r to become negative,
> >       * since C has no well-defined modulo for such cases. */
> >      r = (r+(M_PI*2.5))/(M_PI/4);
> > -    /* this intends to flag 2 directions (90 degrees),
> > +    /* this intends to flag 2 directions (45 degrees),
> >       * except on very well-aligned mickeys. */
> >      i1 = (int)(r+0.1) % 8;
> >      i2 = (int)(r+0.9) % 8;
> 


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