Re: [gentoo-user] Re: line wrap over in xterm/konsole

[Mick]

On Saturday, 22 June 2019 00:44:28 BST Grant Taylor wrote:
> On 6/21/19 5:03 PM, Jorge Almeida wrote:
> > ## equery uses x11-terms/xterm
> > [ Legend : U - final flag setting for installation]
> > [        : I - package is installed with flag     ]
> > [ Colors : set, unset                             ]
> >
> >   * Found these USE flags for x11-terms/xterm-337:
> >   U I
> >   - - Xaw3d    : Add support for the 3d athena widget set
> >   + + openpty  : Use openpty() in preference to posix_openpt()
> >   - - toolbar  : Enable the xterm toolbar to be built
> >   + + truetype : Add support for FreeType and/or FreeType2 fonts
> >   + + unicode  : Add support for Unicode
> >   - - xinerama : Add support for querying multi-monitor screen geometry
> >   through>
> >                  the Xinerama API
> >
> > ~
>
> That's what I expected.

These USE flags are the same like mine.


> > Ah, no, it doesn't. I thought Mick's problem was with the shell.
>
> Ah.

I don't think it is a shell related problem (but may be wrong).  After all 
changing the shell option in .bashrc does not affect the display within the 
xterm window.


> > Shrinking the window truncates the visible lines. Restoring the size
> > doesn't restore the truncated contents.
>
> Agreed.

This is the problem I was describing as 'annoying'. Xterm draws the output 
once to fill in the real estate of the current xterm window, but changing the 
window width does not redraw each line to reflow it across the new window 
width.


> > This was expected. After all, the output of "cat foo" is not processed
> > through readline.
>
> I don't think that readline has anything to do with this.
>
> > Maybe I misunderstood the OP's problem?
>
> Ah.

Apologies for my confusing description - I'll have another go below.


> > (But then, how can rxvt behave differently?)
>
> I don't know about rxvt per say.
>
> But I thought there was a common library (libterm?) used by a number of
> terminal emulators that actually saved the output to a temporary file.
> That way they could re-display the output if (when) the window size changed.

I ran ldd and as is logical I can see there are some differences in the libs 
used by both programs.  Neither of them use libterm.


> After emerging and testing rxvt, yes, it will rewrap the line to the new
> window width.  It seems as if it saves the output as discreet lines and
> re-wraps them individually based on the terminal width.  So, the output
> of an ls -l in a 132 character window, causes each line to be re-wrapped
> (as below) when reducing the window width.
>
> This 40 character wide…
>
> aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
> bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
> cccccccccccccccccccccccccccccccccccccccc
> dddddddddddddddddddddddddddddddddddddddd
>
> …becomes this 30 character wide.
>
> aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
> aaaaaaaaaa
> bbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
> bbbbbbbbbb
> cccccccccccccccccccccccccccccc
> cccccccccc
> dddddddddddddddddddddddddddddd
> dddddddddd

In my systems urxvt will wrap lines when shrinking the width of the window AND 
unwrap them when increasing the width of the window.  This is happening in 
real time as the window expands/contracts.

Again in my systems xterm will truncate lines when shrinking the width of the 
window.  This truncated output is now lost.  Increasing the width of the 
window will not restore the truncated lines.  Scrolling up will now draw lines 
in the new full width of the xterm window, but the truncated lines remain 
truncated and their information is lost.