lapse.lua

--[[
Authors: Fraser McCrossan
         Alfredo Pironti
         Torben S.

An accurate intervalometer script, with pre-focus and screen power off options.
http://chdk.wikia.com/wiki/Lua/Scripts:_Accurate_Intervalometer_with_power-saving_and_pre-focus

Tested on G9, A2000, should work on most cameras.

Requires CHDK version 1.2 (depends on set_lcd_display())

Features:
 - Takes as input frame interval plus total desired run-time (or "endless")
 - displays frame count, frame total, remaining time and free space after each frame
   (in endless mode, displays frame count and elapsed time)
 - "Display" button during frame delays toogles display on and off
 - can turn off the display after a given number of frames
 - can pre-focus before starting then go to manual focus mode
 - use SET button to exit 

 See bottom of script for main loop.
]]

--[[
@title Time-lapse
@param s Secs/frame
@default s 3
@param h Sequence hours
@default h 0
@param m Sequence minutes
@default m 0
@param e Endless?
@default e 1
@range e 0 1
@param f Fix focus at start?
@default f 0
@range f 0 1
@param d Display off frame 0=never
@default d 3
--]]

-- convert parameters into readable variable names
secs_frame, hours, minutes, endless, focus_at_start, display_off_after = s, h, m, (e == 1), (f == 1), d

-- sanitize parameters
if secs_frame <= 0 then
  secs_frame = 1
end
if hours < 0 then
  hours = 0
end
if minutes <= 0 then
  minutes = 1
end
if display_off_after < 0 then
  display_off_after = 0
end


-- display status handling
-- 0 turn off
-- 1 turn on

auto_display_off = (display_off_after > 0) -- set to false as soon as the display status is altered
display_status = 1

function display_on()
  set_lcd_display(1)
  display_status = 1
  auto_display_off = false
end

function display_off()
  set_lcd_display(0)
  display_status = 0
end

function display_toggle()
  if display_status == 1 then
    display_off()
  else
    display_on()
  end
end

-- derive actual running parameters from the more human-friendly input
-- parameters
function calculate_parameters (seconds_per_frame, hours, minutes)
  local ticks_per_frame = 1000 * secs_frame -- ticks per frame
  local total_frames = (((hours * 3600 + minutes * 60) - 1) / secs_frame) + 1 -- total frames
  return ticks_per_frame, total_frames
end

function print_status (frame, total_frames, ticks_per_frame, endless, free)
  if endless then
    local h, m, s = ticks_to_hms(frame * ticks_per_frame)
    print("#" .. frame .. ", " .. h .. "h " .. m .. "m " .. s .. "s")
  else
    if frame < total_frames then
      local h, m, s = ticks_to_hms(ticks_per_frame * (total_frames - frame))
      print(frame .. "/" .. total_frames .. ", " .. h .. "h" .. m .. "m" .. s .. "s/" .. free .. " left")
    else
      print(frame .. "/" .. total_frames .. ", " .. free .. " left")
    end
  end
end

function ticks_to_hms (ticks)
  local secs = (ticks + 500) / 1000 -- round to nearest seconds
  local s = secs % 60
  secs = secs / 60
  local m = secs % 60
  local h = secs / 60
  return h, m, s
end

-- sleep, but using wait_click(); return true if a key was pressed, else false
function next_frame_sleep (frame, start_ticks, ticks_per_frame, total_frames)
  -- this calculates the number of ticks between now and the time of
  -- the next frame
  if frame == total_frames then
    return false
  end
  local next_frame = start_ticks + frame * ticks_per_frame
  local sleep_time = next_frame - get_tick_count()
  if sleep_time < 1 then
    sleep_time = 1
  end
  wait_click(sleep_time)
  return not is_key("no_key")
end

-- delay for the appropriate amount of time, but respond to
-- the display key (allows turning off display to save power)
-- return true if we should exit, else false
function frame_delay (frame, start_ticks, ticks_per_frame, total_frames)
  -- this returns true while a key has been pressed, and false if
  -- none
  while next_frame_sleep (frame, start_ticks, ticks_per_frame, total_frames) do
    -- honour the display button
    if is_key("display") then
      -- reset the display-off counter; if it was enabled, we want the display to shut down again
      -- once the user is done looking at it.
      display_off_frame = frame + display_off_after
      display_toggle()
    end
    -- if set key is pressed, indicate that we should stop
    if is_key("set") then
      return true
    end
  end
  return false
end

-- wait for "name" button click until timeout.
-- returns true if button was clicked, false if timeout expired
function wait_button(timeout, name)
  if timeout < 1 then
    return false
  end
  local cur_timeout = timeout
  local start_time = get_tick_count()
  while cur_timeout > 0 do
    wait_click(cur_timeout)
    if is_key("no_key") then
      -- timeout expired
      return false
    else
      if is_key(name) then
        -- user clicked requested key
        return true
      end
    end
    -- user clicked an unwanted key, we continue sleeping
    local now = get_tick_count()
    local elapsed = now - start_time
    start_time = now
    cur_timeout = cur_timeout - elapsed
  end
    return false
end

-- switch to autofocus mode, pre-focus, then go to manual focus mode
function pre_focus()
  set_aflock(0)
  local try = 1
  while try <= 5 do
    print("Pre-focus attempt " .. try)
    press("shoot_half")
    sleep(2000)
    if get_focus_state() > 0 then
      set_aflock(1)
      return get_focus()
    end
    release("shoot_half")
    sleep(500)
    try = try + 1
  end
  return -1
end

if focus_at_start then
  local got_focus = pre_focus()
  if got_focus < 0 then
    print "Unable to reach pre-focus"
    print("Starting to shoot in 1 second")
    sleep(1000)
  else
    local refocus = true
    while refocus do
      print("Press SET to focus again")
      print("or shooting will start in 1 second")
      refocus = wait_button(1000, "set")
      release("shoot_half")
      if refocus then
        got_focus = pre_focus()
        if got_focus < 0 then
          refocus = false
          print "Unable to reach pre-focus"
          print("Starting to shoot in 1 second")
          sleep(1000)
        end
      end
    end
  end
else
  print("Starting to shoot in 1 second")
  sleep(1000)
end

ticks_per_frame, total_frames = calculate_parameters(secs_frame, hours, minutes)

frame = 1
display_off_frame = display_off_after

print "Press SET to exit"

start_ticks = get_tick_count()

while endless or frame <= total_frames do
  local free = get_jpg_count() - 1 -- to account for the one we're going to make
  if free < 0 then
    print "Memory full"
    break
  end
  print_status(frame, total_frames, ticks_per_frame, endless, free)
  if auto_display_off and frame > display_off_frame then
    display_off()
  end
  shoot()
  if frame_delay(frame, start_ticks, ticks_per_frame, total_frames) then
    display_on()
    print "User quit"
    break
  end
  frame = frame + 1
end

set_aflock(0)
display_on()