Re: Short vectors are not plotted

[Dima K. <gn...@di...>]

Ethan Merritt <eam...@gm...> writes:

> Here's a start. I'll probably commit these changes to CVS when the
> current turmoil settles. After applying this patch there is only one
> call site for term->arrow() in the code base, in draw_clip_arrow().
> Could be I'm missing some complication, but it looks to me that any
> changes needed for your heads-only implementation can be limited to
> this one routine.

Here's a new patch series. These assume your use_draw_clip_arrow.patch
is applied. Again, please apply with 'git am', or let me know what is
unsatisfactory, so that I can address it.

The updates are similar to the last patch series in that some functions
took integers previously, but now they take floating-point values. In a
number of cases, this patch series makes available both flavors: integer
and floating-point. Is this what you had in mind?

And two more related points:

1. This patch uncovered an inconsistency in much of our code: when
converting a floating-point terminal coordinate to an integer one,
sometimes we round (either with (int)(x+0.5) or by calling
axis_map_toint()) and sometimes we floor ( (int)(x) ). Looks like it's
more or less random which one we pick. We should always round, I
suspect. This patch series doesn't attempt to resolve this, but a future
set of patches should.

2. I discovered the issue with the vector fields manifests in two
different ways. For very short vectors, they simply disappear, as we
discussed. For vectors that are short, but not 0-pixels-short, the
arrowheads are still plotted, but the angular resolution becomes very
poor. The patches here resolve both of these.


Thanks.