bug#67604: Motion problems with inline images

[JD Smith <jdtsmith@gmail.com>]

> On Dec 4, 2023, at 1:20 PM, Eli Zaretskii <eliz@gnu.org> wrote:
> 
>> From: JD Smith <jdtsmith@gmail.com>
>> Date: Mon, 4 Dec 2023 12:44:45 -0500
>> Cc: 67604@debbugs.gnu.org
>> 
>> Wonders never cease.  I just picked an 8x16 font and it worked fine, finding the bug at offset=2 (i.e. red svg=148 pixels wide). This was using the build from this morning with your recent xdisp.c fix.  To be sure we’re on the same page, I’ve included again the test code below.
> 
> Now I run it and I get
> 
>   Found Bug at offset -6 = 140 pixels
> 
> but the problem with cursor jumping to "JUMPS HERE" still doesn't
> happen.


OK great.  Is it possible at offset = -6 = 140 pixels the green image has wrapped back onto line 1?  That’s a “false positive” bug.  The layout after my/find-skip-bug has found the magic width must look as in my prior screenshot (with green image at the beginning of screen line 2) or it’s not a real bug.

If it does look correct, from (point-min), any pair of next-line or (vertical-motion 1), should bypass scene line 3 = "pulvinar nibh" and land on screen line 4 = "JUMPS HERE", as that’s the literal test find-skip-bug performs!