X9.lua

local current_screen = 1

-- minimum and maximum FPV frequencies
local min_freq = 5645
local max_freq = 5945

-- Uncomment following two lines for EU
--local min_allowed = 5725
--local max_allowed = 5875

-- minimum and maximum screen x-coordinates for position screen
local min_xpos = 11
local max_xpos = 201

local freq = {
    A = {"5865", "5845", "5825", "5805", "5785", "5765", "5745", "5725"},
    B = {"5733", "5752", "5771", "5790", "5809", "5828", "5847", "5866"},
    E = {"5705", "5685", "5665", "5645", "5885", "5905", "5925", "5945"},
    F = {"5740", "5760", "5780", "5800", "5820", "5840", "5860", "5880"},
    R = {"5658", "5695", "5732", "5769", "5806", "5843", "5880", "5917"}
}

local pos = {
    A = {},
    B = {},
    E = {},
    F = {},
    R = {}
}

-- initialize frequency positions (pos) for screen 2
local function init_func()
    local freq_range = max_freq - min_freq
    local pos_range = max_xpos - min_xpos

    -- populate postion arrays
    for band, freqs in pairs(freq) do
        for i=1,8 do
            pos[band][i] = (tonumber(freqs[i]) - min_freq) / freq_range * pos_range + min_xpos
        end
    end
end

-- returns if a frequency is legal
local function is_legal(freq)
    if max_allowed == nil or min_allowed == nil then
        return true
    else
        return tonumber(freq) > min_allowed and tonumber(freq) < max_allowed
    end
end

-- draw a channel number and border
local function draw_chan(chan, x, y, flags)
    -- draw number
    lcd.drawText(x+2, y+2, chan, SMLSIZE + flags)

    -- draw border
    lcd.drawLine(x,   y,   x+7, y,   SOLID, FORCE)
    lcd.drawLine(x,   y,   x,   y+9, SOLID, FORCE)
    lcd.drawLine(x+7, y,   x+7, y+9, SOLID, FORCE)
    lcd.drawLine(x,   y+9, x+7, y+9, SOLID, FORCE)

    -- clear other pixel(s) inside the border
    if flags ~= INVERS then
        lcd.drawLine(x+1, y+5, x+1, y+5, SOLID, ERASE)
    end
end

-- frequency screen
local function draw_freq_screen()
    lcd.clear()

    -- table coordinates
    local xpos = { 13, 38, 63, 88, 113, 138, 163, 188 }
    local ypos = { A = 12, B = 22, E = 32, F = 42, R = 52 }

    -- draw vertical dividers
    for i=9,209,25 do
        lcd.drawLine(i, 1, i, 59, SOLID, FORCE)
    end

    -- draw horizontal dividers
    for i=10,60,10 do
        lcd.drawLine(1, i, 209, i, SOLID, FORCE)
    end

    -- draw channel numbers
    for i=1,8 do
        lcd.drawText(xpos[i]+7, 2, i)
    end

    -- draw band letters and frequencies
    for band, freqs in pairs(freq) do
        -- draw band letter
        lcd.drawText(2, ypos[band], band)
        -- draw frequencies
        for i=1,8 do
            if is_legal(freqs[i]) then
                lcd.drawText(xpos[i], ypos[band], freqs[i])
            else
                -- fill out box
                lcd.drawFilledRectangle(xpos[i]-4, ypos[band]-2, 26, 10, SOLID)
                lcd.drawText(xpos[i], ypos[band], freqs[i], INVERS)
            end
        end
    end
end

-- position screen
local function draw_pos_screen()
    lcd.clear()

    -- band coordinates
    local ypos = { A = 3, B = 15, E = 27, F = 39, R = 51 }

    -- draw vertical divider
    lcd.drawLine(8, 3, 8, 60, SOLID, FORCE)

    -- draw horizontal dividers
    for i=8,56,12 do
        lcd.drawLine(9, i, 210, i, SOLID, FORCE)
    end

    -- draw band letters and channel boxes
    for band, freqs in pairs(freq) do
        -- draw band letter
        lcd.drawText(2, ypos[band]+2, band, SMLSIZE)
        -- draw channel boxes
        for i=1,8 do
            local flags = 0
            if not is_legal(freqs[i]) then
                flags = INVERS
            end
            draw_chan(i, pos[band][i], ypos[band], flags)
        end
    end
end

local function run_func(event)
    -- handle keypresses
    if event == EVT_MENU_BREAK then
        if current_screen == 1 then
            current_screen = 2
        else
            current_screen = 1
        end
    end

    -- draw current screen
    if current_screen == 1 then
        draw_freq_screen()
    elseif current_screen == 2 then
        draw_pos_screen()
    end
    return 0
end

return { init=init_func, run=run_func }