gif render issues on terminal while using with fzf

[UtsavBalar1231]

I have been trying to find a way to get chafa to work alongside as a image previewer for setting wallpaper. My wallpapers dir contains valid image formats 'png/jpg/gif'. While the static image preview is fine, during gif preview it just vomits on the terminal.

chafa-fzf-reduced.mp4

I have tested many different alternatives such as imgcat, kitty's icat and ueberzugpp. where ueberzugpp is the only one who can render gif preview without any terminal buffer abuse. Kitty and imgcat does not seem to support animated previews.

I have seen many people just putting the --animate off argument. but I would like to see if this can be fixed or hacked in some sense. Because there is nothing faster than chafa on the whole internet afaik.

Snippet from my wallpaper tool 

set_selected_wallpaper() {
	local wallpaper_dir
	wallpaper_dir="$(get_wallpaper_dir)"
	if [ -z "$wallpaper_dir" ]; then
		log_message "ERROR" "Wallpaper directory not found."
		return 1
	fi

	# Check if fzf is installed
	if ! command -v fzf >/dev/null; then
		log_message "ERROR" "fzf is not installed. Cannot select a wallpaper."
		return 1
	fi

	# Use fzf to select a wallpaper
	local preview_cmd
	if [[ -n $KITTY_WINDOW_ID && "$(get_battery_status)" == "Discharging" ]]; then
		preview_cmd="kitty icat --clear --transfer-mode=memory --unicode-placeholder --stdin=no --place=\${FZF_PREVIEW_COLUMNS}x\${FZF_PREVIEW_LINES}@0x0 {}"
	elif command -v chafa >/dev/null; then
		preview_cmd="chafa --clear -s \${FZF_PREVIEW_COLUMNS}x\${FZF_PREVIEW_LINES} {}"
	elif command -v viu >/dev/null; then
		preview_cmd="viu {}"
	else
		log_message "WARNING" "No image preview tool (kitty icat, viu, or chafa) is installed. Preview will not be available."
		preview_cmd="echo 'Preview not available {}'"
	fi

	# Use fzf to select a wallpaper with image preview
	local selected_wallpaper
	selected_wallpaper=$(
		find "$wallpaper_dir" -type f |
			fzf --reverse --border \
				--preview "$preview_cmd" \
				--preview-window=top:75%:wrap
	)
	if [ -z "$selected_wallpaper" ]; then
		log_message "WARNING" "No wallpaper selected."
		return 0
	fi

	# Stop the slideshow and set the selected wallpaper
	stop_slideshow
	if [[ "$selected_wallpaper" == *.gif ]]; then
		log_message "INFO" "Animating GIF wallpaper: $selected_wallpaper"
		animate_gif_wallpaper "$selected_wallpaper"
	else
		log_message "INFO" "Setting static wallpaper: $selected_wallpaper"
		set_wallpaper_fallback "$selected_wallpaper"
	fi

	set_slideshow_status "paused"
	log_message "INFO" "Selected wallpaper set: $selected_wallpaper"
}

Expected behaviour:

uerberzugpp-fzf-reduced.mp4

Environment:

OS   : ArchLinux (6.12.10)
PROC : Intel(R) Core(TM) i7-14700HX
TERM : kitty (0.39.0)
WM   : Hyprland (0.46.0)

[AnonymouX47]

Looks to me like a cursor positioning issue.

Why it happens, I'm not sure but fzf might have something to do with it cos last I checked, cursor positioning works well in your environment (i.e in the bare TE). So, I can't really suggest a solution.

A possible hack that comes to mind right now is to intercept chafa's output and modify/replace the CUU (Cursor Up) sequences emitted. Something like:

chafa --duration inf ... | sed -E -e s/\x1b\[[0-9]+A/\x1b[${PREVIEW_HEIGHT}A/

The PREVIEW_HEIGHT placeholder is where the main thing happens. You may play around with that till you get something that works.

Though I think it's more likely to be successful if the sequence were entirely replaced; seeing your fzf interface is full-screen and uses the alternate buffer (non-scrolling), you'd have a better chance of getting things to work by replacing the CUU sequence all together, as in:

1. By saving and restoring the cursor position e.g:

   tput sc && chafa --duration inf ... | sed -E -e s/\x1b\[[0-9]*A/\x1b8/

2. Absolute cursor positioning e.g

   chafa --duration inf ... | sed -E -e s/\x1b\[[0-9]*A/\x1b[2;2H/

   I'm not sure what the exact row and column positions should be, so you might have to tweak that. It should be the screen position of the top left cell of the fzf preview pane.

* Take note of the --duration inf option. Without it, animations will play through only once due to the piped output. By the way, it'll also cause chafa to stall after outputting still images but I'm not sure that should be much of an issue since I expect fzf to terminate the previewer process before it starts to preview another entry. See the option in the man page for more info.

---

I should also mention that ueberzugpp behaves as it does because it uses overlay windows instead of actual terminal graphics as chafa does but that comes with its own caveats, being a hack itself.

[hpjansson]

Thanks, @AnonymouX47.

Also, --relative on or --relative off could have an effect. Failing that, we should find out which seqs are failing in fzf exactly, and look for a better workaround.

[UtsavBalar1231]

Thanks, @AnonymouX47.

Also, --relative on or --relative off could have an effect. Failing that, we should find out which seqs are failing in fzf exactly, and look for a better workaround.

--relative on seems to work with an tiny annoying issue, its horribly slow now at rendering on the fzf preview.

[hpjansson]

--relative on seems to work with an tiny annoying issue, its horribly slow now at rendering on the fzf preview.

Is fzf bottlenecking it (100% in top), or something else?

[UtsavBalar1231]

--relative on seems to work with an tiny annoying issue, its horribly slow now at rendering on the fzf preview.

Is fzf bottlenecking it (100% in top), or something else?

Does not seems like it, fzf processing stays normal.

• Even chafa is not abusing cycles, which is weird

[UtsavBalar1231]

@hpjansson this is a test for you to see on your computer

https://drive.google.com/file/d/1mjbF5w2T_3z_rdjAKmfkQMNQtY1-APNh/view?usp=drivesdk

unzip and run ./wallpaper-slideshow set

[hpjansson]

Just a note here to say I haven't forgotten about this. Been busy with some IRL stuff and preparing the 1.16 release, and will get to it soon.