arrows are shortened too much

[jasongrout]

Apparently 3 years ago, when I made an update patch for matplotlib, I put in some default shortening of arrows. Matplotlib already shortens its arrows to account for line width, so with my shortening and matplotlib's shortening, arrows were always way shorter than they were intended. This patch removes Sage's default shortening of arrows.

CC: @kcrisman

Component: graphics

Author: Jason Grout

Reviewer: Michael Orlitzky

Merged: sage-5.1.beta1

Issue created by migration from https://trac.sagemath.org/ticket/12836

[jasongrout]

comment:1

Attachment: trac-12836-arrow-shorten.patch.gz

Needless to say, since it's a graphics change, people better look at it so people don't get terribly offended that there arrows look a little better :).

[orlitzky]

Attachment: before.png

[orlitzky]

Attachment: after.png

[orlitzky]

Add a doctest.

[orlitzky]

comment:2

Attachment: sage-trac_12836-review.patch.gz

This change looks fine. The before/after.png show an arrow from the origin to (1,1) before and after the patch. I added a doctest that creates two arrows with different line widths, and checks that their shrinkA and shrinkB values are the same.

There's a chance I'm doing something dumb in the doctest, but positive review otherwise.

[orlitzky]

Reviewer: Michael Orlitzky

[jasongrout]

comment:3

Your doctest patch looks good.

[jdemeyer]

Merged: sage-5.1.beta1