bug#39736: 27.0.60; wrong display of scaled checkerd pattern image

[Eli Zaretskii]

> Date: Mon, 24 Feb 2020 20:05:23 +0100 (CET)
> From: Alan Third <alan@idiocy.org>
> Cc: 39736@debbugs.gnu.org
> 
> > Evaluating the form below, a solid gray square is displayed.
> > 
> > (let ((data "\
> > P1
> > 8 8
> > 01010101
> > 10101010
> > 01010101
> > 10101010
> > 01010101
> > 10101010
> > 01010101
> > 10101010
> > "))
> >   (insert-image (create-image data 'pbm t :scale 8)))
> 
> I believe this is the same as bug#38394. Could you perhaps try the
> patch at
> 
>     https://debbugs.gnu.org/cgi/bugreport.cgi?bug=38394

The OP is on MS-Windows, and the patch is for XRender configurations,
so it won't help, I think.

> > The form below temporally displays another image.
> > The upper side is gray, the lower-left corner is black,
> > and the lower-right corner is white.
> > Once the text cursor gets on the image, the whole image is displayed as
> > a gray square.
> > 
> > (let ((data "P1\n2 2\n01\n10")
> >       (buf (generate-new-buffer "tmp")))
> >   (switch-to-buffer buf)
> >   (insert "\na")
> >   (goto-char (point-min))
> >   (redisplay)
> >   (insert-image (create-image data 'pbm t :scale 16)))
> 
> I tried this and couldn’t replicate it, but I believe I had the patch
> for 38394 applied, so it may be a fix. Alternatively it could be
> related to the way the cursor is drawn on images.

I didn't see any temporary display, either, FWIW.