Should `on-redraw` happen after `on-init`?

[ilyagr]

This continues the conversation from #1767 (comment).

When I run lf r34 with the following config file, I get the following message printed to the console (visible after quitting lf):

$ lf
listen: send: no such client id is connected

Config file:

cmd recol ${{
    w=$(tput cols)
    if [ $w -le 30 ]; then
        set nopreview
        lf -remote "send $id set ratios 1"
    elif [ $w -le 50 ]; then
        lf -remote "send $id set ratios 1:1"
    elif [ $w -le 65 ]; then
        lf -remote "send $id set ratios 3:4"
    elif [ $w -le 95 ]; then  # Was 160
        lf -remote "send $id set ratios 2:3:4"
        set preview
    else
        lf -remote "send $id set ratios 2:2:3:4"
        set preview
    fi
}}
cmd on-redraw :recol
cmd on-init :recol

Commenting out on-redraw fixes the issue to a degree, but I would like recol to be called on terminal size change.

I think the issue is that the first on-redraw happens too early. Perhaps it should happen after on-init.

A separate problem is that, even if on-redraw is commented out, lf already draws the interface by the time on-init is called. So, you get a flash of its original setup before it gets replaced by the result of the recol.

---

Workaround

I think there's a workaround of changing the on-init to

cmd on-init : set user_enable_recol true; recol
# Or, equivalently,
cmd on-init :{{
   set user_enable_recol true
   recol
}}

and checking the value of $lf_user_enable_recol inside cmd recol.

This does not fix the flash of the wrong number of columns before lf redraws.

Update: More precisely, here is the diff that seems to be a working workaround:

--- lfrc-bug	2025-02-11 18:14:14
+++ lfrc-workaround	2025-02-11 18:25:22
@@ -1,5 +1,9 @@

 cmd recol ${{
+    if [ "${lf_user_allow_recol-no}" = no ]; then
+       exit 0
+    fi
+
     w=$(tput cols)
     if [ $w -le 30 ]; then
         set nopreview
@@ -17,4 +21,4 @@
     fi
 }}
 cmd on-redraw :recol
-cmd on-init :recol
+cmd on-init :set user_allow_recol true; recol

---

Workaround 2

Or, I can set noautoquit, and then this message is printed only once no matter how many times I start lf. Update: Also, this solves the visual refresh problem.

[DusanLesan]

Can't we do this as a workaround?

cmd on-init :recol; cmd on-redraw recol

[ilyagr]

That's an interesting idea. To clarify a bit, what Dusan means is equivalent to:

cmd on-init :{{
   recol
   cmd on-redraw recol
}}

This is a bit cleverer than the workaround I suggested, but is equivalent in terms of the outcome, with the same downside of seeing a refresh happen on the screen.

[ilyagr]

Perhaps documenting this trick would be a good enough outcome, unless there is some way to fix the visible refresh issue as well.

Update: BTW, I also realized that set noautoquit solves the visual refresh problem, except for the very first time I start lf.

[joelim-work]

The tip currently assumes that the server is started beforehand, since on-redraw is triggered very early during startup and also requires the use of lf -remote. I think the idea of assigning on-redraw during the on-init hook is quite nice - an alternate way to express it would be like this:

cmd on-init :{{
    cmd on-redraw %{{
        if [ "$lf_width" -le 80 ]; then
            lf -remote "send $id set ratios 1:2"
        elif [ "$lf_width" -le 160 ]; then
            lf -remote "send $id set ratios 1:2:3"
        else
            lf -remote "send $id set ratios 1:2:3:5"
        fi
    }}

    on-redraw
}}

---

Regarding the visible refresh upon startup, I'm not sure if there is any good solution, since it would need to meet the following requirements:

1. The UI (with the updated number of columns) should be shown as early as possible
2. The number of columns can only be updated via lf -remote, since the lf config language is minimal and requires the shell to handle if/else constructs
3. lf -remote requires the server to be initialized - this is fine if the user starts it beforehand, but if the user doesn't want it then it takes some time for lf to start it automatically.

[ilyagr]

Thanks!

I updated the tip you linked to, PTAL and edit it further if necessary.

Also, I previously used ${{ and tput cols for this. Switching to %{{ and $lf_width improved the situation noticeably (though it didn't fix it 100%).

I'm also unsure whether more can or should be done.

[joelim-work]

It looks fine, but one small point - just wondering if users have success starting the lf server as part of startup/login script for their system, so that the refresh issue doesn't happen the first time either because lf never has to start the server at all.

[ilyagr]

I didn't know this was possible. Is it written up somewhere (I very likely just haven't noticed it)? It'd make sense to either add to my advice or replace my advice with a link about how to do that.

[joelim-work]

I thought this kind of thing was possible using profile scripts (there are probably other ways as well). Anyway I updated the wiki to mention this possibility but didn't go into details since it's dependent on the user's system.

[ilyagr]

Perhaps lf should have a -background-server option that starts a server in the background. It's probably equivalent to something like lf -server 2>&1 >/dev/null & disown, but would be easier to remember.

I'm also not sure it's worth it for fixing the one-time-for-each reboot inconvenience. (Updated: and I edited that tip once more to mention that set autoquit false is probably sufficient for most people)

[joelim-work]

I think the -server option was intended so that the lf server could be started independently, and the circumstances in which it is done so is up to the user. I'm not really inclined to add another option just to start it as a background process - I feel it goes against the minimalistic nature of lf, and it is something that could be solved better with documentation (e.g. adding it as a separate section in wiki tips). If anyone has a good example, I'm happy for it to be added in.