bug#32932: 27.0.50; render bugs on macOS Mojave

[Aaron Jensen <aaronjensen@gmail.com>]

On October 31, 2018 at 11:13:53 PM, Boris Buliga
(boris@d12frosted.io(mailto:boris@d12frosted.io)) wrote:

> Yes, I've also noticed blanks with ivy.
>
> But for sure this patch is a HUGE improvement. I had to work a little bit on a
> machine where I didn't install this patch and I have encountered a lot of random
> blanks.
>
>
> --------------------------------------------------------------------------------
>
> Aaron,
>
> I will hopefully be able to test with the following line commented out.
>
> w->phys_cursor_on_p = on_p;

Just commenting that out will cause the cursor to ghost, but it fixes
the problem for me otherwise. Tracing further, it seems that that
getting set causes erase_phys_cursor to get called, which ultimately
calls draw_phys_cursor_glyph, which calls draw_glyphs, which I believe
is what is blanking the line. It appears to be more than just
redrawing the glyph under the cursor.

Another clue is that it appear to only blank from where the cursor is
to the end of the line. Anything before that isn’t cleared.

I’m sure I’m at the end of my depth here w/o diving a lot deeper.
Hopefully this flurry of emails points you in the right direction,
Alan. Thanks!

Aaron