Subject: bug#26133: 25.1; XBM images broken - worked in 24.3

From: Lars Ingebrigtsen <[email-masked]>
Date: Fri, 26 Jul 2019 13:47:00 +0200

"Devon Sean McCullough" <[email-masked]> writes:

> ; Please find attached screen shots of this Emacs 24.3 vs. Emacs 25.1 bug:
> (progn (insert-image (create-image "/* Example at
> https://en.Wikipedia.org/wiki/X_BitMap */
> #define test_width 16
> #define test_height 7
> static char test_bits[] = { 0x13, 0x00, 0x15, 0x00, 0x93, 0xcd, 0x55,
> 0xa5, 0x93, 0xc5, 0x00, 0x80,0x00, 0x60 };"
> 				   (quote xbm) t))
>        (insert emacs-version))
> ; MacOS 10.11.6 Emacs 24.3 displays a proper [Blarg] glyph.
> ; MacOS 10.11.6 Emacs 25.1 displays a scrambled [alBgra] glyph with the
> "a" split in two, i.e., [Blarg] glyph with each octet LSB-MSB reversed.
>
> It seems in XBM image bool-vector data
>
>     (A) octets are sometimes little-endian and sometimes big-endian
>     (B) rows are sometimes padded to octet boundaries and sometimes not
>
> It would be helpful to standardize -- or at least document -- such
> per-version per-platform differences
> as XBM is the only programmatically accessible graphical element natively
> supported in vanilla Emacs!

I'm unable to reproduce this bug with Emacs 27 on GNU/Linux -- are you
still seeing this problem?  The image code has gotten a lot of work in
the years after you reported this problem...

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no