Dynamically Toggle Between Colour Schemes in Existing Tabs and Windows Without Recompiling

[craigem]

I've been wondering about how to load the Solarized themes and switch between light and dark with a key stroke toggle.

This should be possible, but will require changing a few things.

You'll have to send a PR to add a hook that gets called right as Termonad is about to launch. Probably around here:

termonad/src/Termonad/App.hs

Lines 421 to 422 in db185e3

	widgetShowAll win
	widgetGrabFocus $ terminal ^. lensTerm

In your own config, you'll have to override that hook to define a new key binding for each existing terminal.

Here's an example of defining a key binding (this code defines the Alt-1, Alt-2, etc bindings for switching tabs):

https://github.com/cdepillabout/termonad/blob/db185e34a4b678183d8d1b1ce0be4c8bf3532fc8/src/Termonad/Keys.hs

termonad/src/Termonad/Term.hs

Lines 345 to 346 in db185e3

	void $ onWidgetKeyPressEvent vteTerm $ handleKeyPress mvarTMState
	void $ onWidgetKeyPressEvent scrolledWin $ handleKeyPress mvarTMState

Your key binding will have to call a function that loops through all the open tabs and sets the colors for the terminal.

Here's where that is currently being done:

termonad/src/Termonad/Config/Colour.hs

Lines 453 to 479 in db185e3

	-- | The default 'createTermHook' for 'colourExtCreateTermHook'. Set the colors
	-- for a terminal based on the given 'ColourConfig'.
	colourHook :: MVar (ColourConfig (Colour Double)) -> TMState -> Terminal -> IO ()
	colourHook mvarColourConf _ vteTerm = do
	colourConf <- readMVar mvarColourConf
	terminalSetColors vteTerm Nothing Nothing . Just
	=<< traverse toRGBA (paletteToList . palette $ colourConf)
	-- PR #28 / issue #29: Setting the background colour is broken in gi-vte or VTE. If
	-- this next line is called, then you are no longer able to set the
	-- background color using the palette.
	-- terminalSetColorBackground vteTerm =<< toRGBA (backgroundColour colourConf)
	terminalSetColorForeground vteTerm =<< toRGBA (foregroundColour colourConf)
	let optPerform setC cField = whenSet (cField colourConf) $ \c ->
	setC vteTerm . Just =<< toRGBA c
	optPerform terminalSetColorCursor cursorBgColour
	#ifdef VTE_VERSION_GEQ_0_44
	optPerform terminalSetColorCursorForeground cursorFgColour
	#endif
	where
	toRGBA :: Colour Double -> IO RGBA
	toRGBA colour = do
	let RGB red green blue = toSRGB colour
	rgba <- newZeroRGBA
	setRGBARed rgba red
	setRGBAGreen rgba green
	setRGBABlue rgba blue
	pure rgba

This is only setting colors for a single terminal, so you'll have to change it so it loops through all tabs.

Here's a function that loops through all tabs (although this is changing the font size):

termonad/src/Termonad/App.hs

Lines 192 to 199 in db185e3

	let terms =
	tmState ^..
	lensTMStateNotebook .
	lensTMNotebookTabs .
	traverse .
	lensTMNotebookTabTerm .
	lensTerm
	foldMap (\vteTerm -> terminalSetFont vteTerm (Just fontDesc)) terms

Originally posted by @cdepillabout in #94 (comment)

[craigem]

For the record, I am happy to work on this (probably as soon as next week), I just felt a new issue was appropriate as I felt we'd strayed from the original issue's remit, @cdepillabout

[cdepillabout]

@craigem Thanks for copying this issue over!

I'd definitely accept something like this if you wanted to take a shot at implementing it. Looking forward to the PR!

[dopamane]

First of all, @cdepillabout thanks for making termonad, its awesome and I use it every day 🚀 . I came across this issue because I need to switch backgrounds due to coding indoors, outdoors, day and night.

I took a crack at it here. I'm happy because it works fine for my needs. I figured I'd share and maybe get some feedback on how I could extend it and eventually get it mergeable. Maybe it will give an idea about how to adjust termonad to make it more extensible too.

I skipped the key binding hook because I thought it was an orthogonal issue. A key binding hook would be very useful, and my foray into termonad today has given me a better idea of how to do so! I skipped the looping through all tabs because I don't use tabs, but it seems straightforward. Sorry. I'll need to go back and fix that to make it mergeable.

I'm not sure how to handle multiple colour configurations. In my personal termonad config I use addColourConfig, which the docs indicate adds colourHook to the createTermHook. I could imagine a TMConfig with a list of ColourConfig. Then addColourConfigs would add a colourHook of the first element. Or maybe defaultMain can handle adding a colourHook to createTermHook of the first element in our TMConfig ColourConfig list. Then using a key binding hook, the user can use TMState to gain access to their ColourConfig list, call colourHook and cycle through the list.

[dopamane]

I'll give #83 a shot today, adding extensible keys, then come back to dynamic color configurations.

[dopamane]

#248 Adds basic key map configuration. Then I leveraged the key map to toggle between two themes here dopamane#2 Its extensible, unlike my earlier toggle solution.