Re: [Matplotlib-users] ugly arrow with xpdf

[Friedrich H. <fri...@gm...>]

On Mon, Jun 02, 2008 at 11:17:44PM +0300, Jouni K. Seppänen wrote:
> I can confirm this in at least version 0.91.3. The problem seems to be
> caused by the midpoint of the stem being included in the path twice in a
> row. The following patch removes the midpoint altogether and fixes the
> rendering problem at least on my version of xpdf. I'm kind of swamped
> right now, so I hope someone else can check whether this breaks any
> other uses of arrows, or some other backend. (If this doesn't seem to
> happen, please file a bug report in the tracker so it isn't forgotten.)
> The patch is against the maintenance branch, but the trunk has
> similar-looking code.

Thank you very much. It works for me too.

> Index: lib/matplotlib/patches.py
> ===================================================================
> --- lib/matplotlib/patches.py (revision 5366)
> +++ lib/matplotlib/patches.py (working copy)
> @@ -634,7 +634,13 @@
>                  if shape == 'right':
>                      coords = right_half_arrow
>                  elif shape == 'full':
> -                    coords=npy.concatenate([left_half_arrow,right_half_arrow[::-1]])
> +                    # Concatenating the full paths caused the midpoint
> +                    # of the stem to be included twice, which was
> +                    # rendered badly by xpdf. Since the point is right
> +                    # between the corners of the stem, we can drop it
> +                    # from both halves.
> +                    coords=npy.concatenate([left_half_arrow[:-1],

for the most recent svn version: npy => np

> +                                            right_half_arrow[-2::-1]])
>                  else:
>                      raise ValueError, "Got unknown shape: %s" % shape
>              cx = float(dx)/distance

By,

  Friedrich