bling/layout/centered.lua

local awful = require("awful")
local gears = require("gears")
local gcolor = require("gears.color")
local beautiful = require("beautiful")
local math = math

local mylayout = {}

mylayout.name = "centered"

function mylayout.arrange(p)
    local area = p.workarea
    local t = p.tag or screen[p.screen].selected_tag
    local mwfact = t.master_width_factor
    local nmaster = math.min(t.master_count, #p.clients)
    local nslaves = #p.clients - nmaster

    local master_area_width = area.width * mwfact
    local slave_area_width = area.width - master_area_width
    local master_area_x = area.x + 0.5 * slave_area_width

    local number_of_left_sided_slaves = math.floor(nslaves / 2)
    local number_of_right_sided_slaves = nslaves - number_of_left_sided_slaves
    local left_iterator = 0
    local right_iterator = 0

    -- Special case: no maters -> rrelapse into awesomes fair layout
    if t.master_count == 0 then
        awful.layout.suit.fair.arrange(p)
        return
    end

    -- Special case: one slave -> relapse into awesomes masterstack tile layout
    if nslaves == 1 then
        awful.layout.suit.tile.right.arrange(p)
        return
    end

    -- Special case: no slaves -> fullscreen master area
    if nslaves < 1 then
        master_area_width = area.width
        master_area_x = area.x
    end

    -- iterate through masters
    for idx = 1, nmaster do
        local c = p.clients[idx]
        local g
        g = {
            x = master_area_x,
            y = area.y + (nmaster - idx) * (area.height / nmaster),
            width = master_area_width,
            height = area.height / nmaster,
        }
        p.geometries[c] = g
    end

    -- iterate through slaves
    for idx = 1, nslaves do -- idx=nmaster+1,#p.clients do
        local c = p.clients[idx + nmaster]
        if idx % 2 == 0 then
            g = {
                x = area.x,
                y = area.y
                    + left_iterator
                        * (area.height / number_of_left_sided_slaves),
                width = slave_area_width / 2,
                height = area.height / number_of_left_sided_slaves,
            }
            left_iterator = left_iterator + 1
        else
            g = {
                x = area.x + master_area_width + slave_area_width / 2,
                y = area.y
                    + right_iterator
                        * (area.height / number_of_right_sided_slaves),
                width = slave_area_width / 2,
                height = area.height / number_of_right_sided_slaves,
            }
            right_iterator = right_iterator + 1
        end
        p.geometries[c] = g
    end
end

local icon_raw = gears.filesystem.get_configuration_dir()
    .. tostring(...):match("^.*bling"):gsub("%.", "/")
    .. "/icons/layouts/centered.png"

local function get_icon()
    if icon_raw ~= nil then
        return gcolor.recolor_image(icon_raw, beautiful.fg_normal)
    else
        return nil
    end
end

return {
    layout = mylayout,
    icon_raw = icon_raw,
    get_icon = get_icon,
}