Re: Reverting various commits

[Dave Kemper]

On 5/21/21, G. Branden Robinson <g.branden.robinson@gmail.com> wrote:
> The last is useful to catch almost anything that might go wrong in PS
> or PDF output, without the tedium of visually comparing such output.

Two other possibilities for scriptably regression-testing PS/PDF output:

* In cases, like man pages, that aren't doing a lot of tricky
typesetting maneuvers (e.g., dropping the E in the middle of TEX),
saving expected "groff -a" output and then diffing new runs against
that often reveals when things change on the typeset page.

* The diffpdf.py script
(http://github.com/brechtm/rinohtype/blob/stable/tests_regression/helpers/diffpdf.py),
which is an updated version of the script I posted about in January
(http://lists.gnu.org/archive/html/groff/2021-01/msg00101.html),
compares pixels on the page of two PDFs.