dotfiles/awesome/rc_parts/constrain.lua

-- init -- {{{1
-- luacheck: globals mouse
local mouse = mouse
local root = client
local naughty = require('naughty')

local state = {
	client = nil,
	signals = {},
}

local function notify(msg, keep) -- {{{1
	local timeout = 3
	if keep then
		timeout = 0
	end

	naughty.notify({ text = msg, timeout = timeout })
end

local function set_bounds() -- {{{1
	local c = state.client
	state.x_min = c.x + 5
	state.x_max = c.x + c.width - 5
	state.y_min = c.y + 5
	state.y_max = c.y + c.height - 5
end

local function reposition() -- {{{1
	local pos = mouse.coords()
	local new_pos = {}

	if pos.x > state.x_max then
		new_pos.x = state.x_max
	elseif pos.x < state.x_min then
		new_pos.x = state.x_min
	else
		new_pos.x = pos.x
	end

	if pos.y > state.y_max then
		new_pos.y = state.y_max
	elseif pos.y < state.y_min then
		new_pos.y = state.y_min
	else
		new_pos.y = pos.y
	end
	--new_pos.x = state.x_min + (state.x_max - state.x_min) / 2
	--new_pos.y = state.y_min + (state.y_max - state.y_min) / 2

	mouse.coords(new_pos, false)
end

local function connect(signal, func) -- {{{1
	state.client:connect_signal(signal, func)
	state.signals[signal] = func
end

local function disconnect() -- {{{1
	for signal, func in pairs(state.signals) do
		state.client:disconnect_signal(signal, func)
		state.signals[signal] = nil
	end
end

local function release() -- {{{1
	disconnect()

	root.disconnect_signal('mouse::move', reposition)
	root.disconnect_signal('mouse::leave', reposition)

	notify('Mouse released')

	state.client = nil
end

local function constrain(c) -- {{{1
	state.client = c or mouse.current_client

	if state.client == nil then
		return
	end

	set_bounds()

	notify('Constrainging mouse to ' .. state.client.name)

	root.connect_signal('mouse::move', reposition)
	root.connect_signal('mouse::leave', reposition)

	connect('mouse::move', reposition)
	connect('mouse::leave', reposition)
	connect('property::size', set_bounds)
	connect('property::position', set_bounds)
	connect('unmanage', release)
end

-- public interface -- {{{1
return {
	constrain = constrain,
	release = release,
	toggle = function(c)
		if state.client then
			release()
		else
			constrain(c)
		end
	end,
}