Keyboard example (LÖVE 11.X)

function love.load()
    local prelayout = {"abcdefg", "hijklmn", "opqrstu", "vwxyz"}

    layout = {}
    for y = 1, #prelayout do
        layout[y] = {}
        for x = 1, string.len(prelayout[y]) do
            layout[y][x] = {key = string.sub(prelayout[y], x, x), pressed = false}
        end
    end

    startX, startY = 10, 10
    keySize = 20
    spacing = 5

    windowW = #layout[1]*(keySize + spacing) - spacing + 2*startX
    windowH = #layout*(keySize + spacing) - spacing + 2*startY

    love.graphics.setBackgroundColor(1, 1, 1)
    font = love.graphics.newFont(12)
    love.graphics.setFont(font)

    love.window.setMode(windowW, windowH)
end

function love.draw()
    for y = 1, #layout do
        for x = 1, #layout[y] do
            local px, py = startX + (x-1)*(keySize + spacing), startY + (y-1)*(keySize + spacing)
            local v = layout[y][x].key
            love.graphics.setColor(39/255, 151/255, 229/255, 155/255)
            if layout[y][x].pressed then
                love.graphics.setColor(229/255, 218/255, 39/255, 155/255)
            end
            love.graphics.rectangle("fill", px, py, keySize, keySize)
            love.graphics.setColor(0, 0, 0, 1)
            love.graphics.rectangle("line", px, py, keySize, keySize)
            love.graphics.print(v, px + keySize/2 - font:getWidth(v)/2, py + keySize/2 - font:getHeight()/2)
        end
    end
end

function love.mousepressed(x, y, button)
    local px, py = x - startX, y - startY
    --Clicked inside keyboard
    if px >= 0 and py >= 0 and px <= (keySize+spacing)*#layout[1] and py <= (keySize+spacing)*#layout then
        local tx, ty = math.floor(px/(keySize+spacing)) + 1, math.floor(py/(keySize+spacing)) + 1
        px = px - (tx-1)*(keySize+spacing)
        py = py - (ty-1)*(keySize+spacing)

        --If in-between keys, ignore
        if px <= keySize and py <= keySize then
            print("KEY: " .. layout[ty][tx].key)
            layout[ty][tx].pressed = not layout[ty][tx].pressed
            return
        end
    end
    print("Outside keyboard")
end