How to configure the "+" new_tab_button_in_tab_bar

[ChrisGVE]

I've extensively customized my tab_active, tab_inactive, and I'd like to customize the "+" pseudo-tab. I know I could use

options.tab_separator  = {
   left = "...",
   right = "...",
}

But this interferes with my config of tab_[in]active. Is there a way to explicitly customize the "+"?

For reference my tab_bar is looking like so:

And my configuration is

local nerdfonts = wezterm.nerdfonts

local LOWER_LEFT_WEDGE = nerdfonts.ple_lower_left_triangle
local UPPER_LEFT_WEDGE = nerdfonts.ple_upper_left_triangle
local LOWER_RIGHT_WEDGE = nerdfonts.ple_lower_right_triangle
local UPPER_RIGHT_WEDGE = nerdfonts.ple_upper_right_triangle

tabline.setup({
	options = {
[...]
		tab_separators = {
			left = "",
			right = "",
		},
	},

[...]

		-- ACTIVE TAB

		tab_active = {
			{ Attribute = { Intensity = "Bold" } },
			{ Foreground = { Color = scheme.tab_bar.active_tab.fg_color } },
			{ Background = { Color = scheme.selection_fg } },
			UPPER_LEFT_WEDGE,
			function(tab)
				return tab.tab_index + 1
			end,
			{ Foreground = { Color = scheme.selection_fg } },
			{ Background = { Color = tabline_scheme.tab.active.bg } },
			UPPER_LEFT_WEDGE,
			"ResetAttributes",
			get_tab_icon,
			{ Attribute = { Intensity = "Bold" } },
			" ",
			function(tab)
				return get_cwd(tab)
			end,
			" ",
			zoomed,
			" ",
			{ Foreground = { Color = tabline_scheme.tab.active.bg } },
			{ Background = { Color = tabline_scheme.tab.inactive.bg } },
			UPPER_LEFT_WEDGE,
			" ",
		},

		-- INACTIVE TAB

		tab_inactive = {
			{ Attribute = { Italic = true } },
			{ Foreground = { Color = scheme.selection_bg } },
			{ Background = { Color = scheme.tab_bar.active_tab.fg_color } },
			LOWER_RIGHT_WEDGE,
			{ Foreground = { Color = scheme.tab_bar.inactive_tab.fg_color } },
			{ Foreground = { Color = scheme.tab_bar.inactive_tab.fg_color } },
			{ Background = { Color = scheme.selection_bg } },
			function(tab)
				return tab.tab_index + 1
			end,
			{ Foreground = { Color = scheme.selection_bg } },
			{ Background = { Color = tabline_scheme.tab.inactive.bg } },
			UPPER_LEFT_WEDGE,
			"ResetAttributes",
			-- has_unseen_output_attribute,
			has_unseen_output_bell,
			"ResetAttributes",
			get_tab_icon,
			{ Attribute = { Italic = true } },
			get_process_name,
			" ",
			get_cwd_postfix,
			{ Foreground = { Color = tabline_scheme.tab.inactive.bg } },
			{ Background = { Color = tabline_scheme.tab.inactive.bg } },
			UPPER_LEFT_WEDGE,
			" ",
		},

[michaelbrusegard]

I have not built in any customisation of the + icon into the plugin. I dont know how it can be customised. What is the issue you are having that makes it interfere with the plugin?

[ChrisGVE]

Ok, when I change the options to

		tab_separators = {
			left = LOWER_RIGHT_WEDGE,
			right = LOWER_RIGHT_WEDGE,
		},

I get the following result:

The first highlight shows an undesired character that interferes with my customization, the second highlight shows that the "+" receives the correct left character, but the third highlight shows that there is no character on the right of the "+" (actually none for any tab).

So I'm not sure how to proceed, except maybe giving up 😉

[michaelbrusegard]

I understand now. I think the issue is with the icon and how it is being colored. So the icons foreground color and background color is reversed to what the plugin expects. I think you can try to swap the colors in the config and that may fix it, but I am not 100% sure

[ChrisGVE]

Ok, that's a good idea; I'll give it a go and revert.

On another topic, you recall that we had an exchange about setting attributes programmatically (I'm not sure which forum it was, sorry).

I had a function like this

local function has_unseen_output_attribute(tab, opts)
	local result = { Foreground = { Color = "blue" } }
	for index, pane in ipairs(tab.panes) do
		if pane.has_unseen_output then
			result = { Foreground = { Color = "red" } }
		end
	end
	return result
end

You can see the call commented out in my config snippet above.

But it was giving me an error:

18:46:47.331 WARN wezterm_gui::tabbar > format-tab-title: runtime error: ...michaelbrusegardsZstablinesDswez/plugin/tabline/util.lua:109: attempt to concatenate a table value
stack traceback:
        [C]: in metamethod 'concat'
        ...michaelbrusegardsZstablinesDswez/plugin/tabline/util.lua:109: in function 'tabline.util.extract_components'
        ...michaelbrusegardsZstablinesDswez/plugin/tabline/tabs.lua:46: in upvalue 'create_tab_content'
        ...michaelbrusegardsZstablinesDswez/plugin/tabline/tabs.lua:75: in function 'tabline.tabs.set_title'
        (...tail calls...)

And I wasn't sure what to do to make it right.

[michaelbrusegard]

I have added a component for unseen output that you can use. It is in the documentation so you dont have to create your own

[ChrisGVE]

Sweet, thanks a lot!