[racket] That path issue looks related to bitmaps

Bitmaps created by `make-bitmap' and bitmaps created with
`make-platform-bitmap'/`make-screen-bitmap' use different renders, at
least under Mac OS X and Windows. The former uses Pixman (on all
platforms), while the latter uses a platform-native renderer.

So, that's why there's a difference, although I'm not sure why Pixmap
drops a line. The smoothing mode has something to do with it. That is,
depending on the goal and context, the right workaround may be `(send
dc set-smoothing 'smoothed)'.

At Sun, 17 Feb 2013 15:27:55 -0700, Danny Yoo wrote:
> Hi Jens,
> 
> That issue that you brought up in IRC: it's the bitmap, not the path.
> The path is actually looking ok.  Here's a test program to show the
> issue.
> 
>     https://gist.github.com/dyoo/4973820
> 
> Comment out the make-bitmap in favor of one of the other two bitmap
> constructors on Mac OS X.  In the original program, under Mac OS X,
> the right edge of the glyph doesn't draw for some reason.  But it does
> under the other bitmaps.  So something funky is happening.