What is Lua ?
Lua is a powerful, fast, light-weight, embeddable scripting language. Lua combines simple procedural syntax with powerful data description constructs based on associative arrays and extensible semantics. Lua is dynamically typed, runs by interpreting bytecode for a register-based virtual machine, and has automatic memory management with incremental garbage collection, making it ideal for configuration, scripting, and rapid prototyping. (quoted from www.lua.org)
Lua was brought to CHDK by "Velo" in the forum in April 2008: Lua Scripting Integration
License: Lua is Open Source software, its licenses are compatible with GPL.
Important Links
Lua dependent CHDK wikia articles:
External links:
Running Lua scripts
- A CHDK version with built-in Lua support is needed, e.g. CHDK builds > version 0.5 / changeset 512
- The script should be saved with the filename extension .lua in the CHDK scripts folder chdk/scripts
- Lua scripts support libraries, these files have to be placed either in chdk/scripts or chdk/lualib, see Lua syntax: Libraries.
- Loading, starting, pausing & stopping work exactly in the same way as on UBASIC scripts
- UBASIC scipts are also working as usual, the filename extension (.lua or .bas) tells CHDK how to run the script
- For advanced Lua development, you may wish to run scripts on your computer. Set up a Lua Dev Environment
A first Lua sample script:
for i = 1,10 do
print( "Picture "..i )
shoot()
sleep( 2000 )
end
Lua standard libraries: io, os, string, and math
CHDK has included experimental support for the lua standard IO and OS libraries since changeset 517. These allow you to manipulate files and directories. See this post for important differences, limitations and warnings.
Support for the string library has been added in changeset 606.
Support for the math library exists in a modified form. Lua numbers are floats but chdk lua uses 32bit ints instead. The portions of the math library that make sense for ints are included.
→ A test script to check the correct functionality of the library functions (including a list of successfully tested cameras) is also available: Lua IO+OS library test !
Differences from standard lua iolib
Missing features
- io.popen: CHDK has no other processes, no pipes
- standard file handles: stdin/stdout/stderr all start out closed, as do io.input() and io.output()
- io.tmpfile: Not implemented yet, but may be added later.
Added features
- file:_getfptr()
- fptrval=file:_getfptr()
- Returns the actual FILE * associated with the file object. This is strictly for development/debugging, but combined with peek makes verifying FILE structure hack much simpler.
Other differences
- Error detection and reporting is more limited:
- vxworks reports errno, but no text description
- dryos has no errno (or not found until now), and simply reports "error"
- file:read("*n") will behave slightly differently because it doesn't use scanf. Shouldn't matter for sanely structured files, but corner cases will be different.
Differences from standard lua oslib
Missing features
- os.clock: not implemented. Note this relates to CPU time used by a process, not time of day (which is handled by os.time and os.date)
- os.execute: no processes, revisit for ELF edition
- os.exit: not meaningful for CHDK
- os.getenv: environment variables exist in vxworks, but usefulness is doubtful
- os.setlocale: functions may exist, but it's unlikely the rest of the firmware uses them
- os.tmpname: TODO, not implemented yet (a beta implementation is available in the forum). Also trivial to implement entirely in lua script.
Added features
The following are not in the standard lua OS lib, but are added in CHDK
- os.mkdir
- status[,errstring[,errno]]=os.mkdir("A/path")
- Attempts to create a directory at the named path. Returns true on success or nil,"error string",errno.
- os.stat (implemented since build 0.6.5 / changeset 541)
- stat_table[,errstring[,errno]=os.stat("filename")
- Returns a table on success, or nil followed by the values of strerror and errno
- The table has the following fields (all numbers)
dev device number mode not clear which bits are useful. It does change depending on whether you look at a file or directory (but you should use attrib or is_* below instead) size size in bytes atime time of last access mtime time of last modification ctime time of last change of file status blksize block size in bytes. This is NOT the dos sector size. 512 on all I've tested, possibly hardware block size. blocks Number of blksize blocks in the file. blocks*blocksizes is not the same as "size on disk", per above. attrib bitmask of dos attributes (see stdlib.h)
- The following boolean values are set based on attrib, so you don't have to do bit testing for the most common values of interest:
- is_dir
- is_file
- Notes:
- It is possible to stat things that are neither file nor directory, e.g. volume labels. So you should test for exactly what you want, rather than assuming that not is_file means directory.
- Files larger than 2gb would appear to have a negative size in lua.
- os.utime (implemented since build 0.6.5 / changeset 541)
- status[,errstring[,errno]]=os.utime("filename"[,atime[,mtime]])
- Set the modification and access time of the named file. If either time is missing or nil, the current time is used. Returns true on success, or nil, "error message", errno. To set one time and leave the other unchanged, you must use stat to get the current value.
- os.listdir (implemented since build 0.7.4 / changeset 555)
- dir_table[,errstring[,errno]]=os.listdir("dirpath"[,showall])
- List the contents of a directory. Returns array of file names, or nil, "error message", errno.
- If showall is true, the array includes ".", ".." and deleted entries
- Sample/Usage: see Lua#Listdir_sample
- Notes:
- Except for the root directory, names ending in / will not work. (untested on DryOS)
- DryOS only returns 8.3 names. VxWorks returns long names.
- DryOS will report success and return an empty table if you call listdir on a file.
Other differences
- Similar error reporting limitations to io
- os.date: Does not distinguish between local and GMT. It's possible support could be added for some cameras.
- os.difftime: Just returns (unsigned int)t1 - (unsigned int)t2
General notes from IO and OS testing on vxworks
- os.remove works on files and empty directories. Attempting to remove a non-empty directory fails gracefully.
- os.rename works on files and empty directories. Attempting to rename a non-empty directory may result in filesystem corruption !
- os.rename only works within a given directory. You can not use rename to move a file to another directory. Attempting to do so may cause unpredictable results.
- os.rename may produce unpredictable results if the target name already exists.
- os.mkdir will not create a directory if the name has a trailing /, but fails gracefully
- io functions are very likely limited to files of less that two gigabytes, and certainly less than four.
- unlike some OSes, file:seek cannot be used to extend a file
Future versions should attempt to handle some of these situations more gracefully. Dryos may behave differently.
The string library
Unlike io and os, the string library does not differ substantially from the lua standard. If it fails on your camera, the worst result is likely to be a crash.
Lua library test
If the libraries have not already been tested on your camera and firmware version, you should run the script before attempting to use them. This script tests the various IO and OS functions, generating /llibtst.log and reporting pass or fail in the console. If not all tests are run, or there are failures, it may leave other files or directories in the root.
Failures could crash your camera. It is also possible, although not likely, that it could corrupt your SD card. Use caution if your camera has not been tested. |
The following cameras have been successfully tested as of February 14, 2010:
a470-102c a540-100b a550-100c a560-100a a570-1.00e a570-101a a590-101b a620-100f a630-100c a650-1.00d a710-100a a720-100c ixus40_sd400-1.01b ixus70_sd1000-101b ixus80_sd1100-100c ixus850_sd800-100e ixus860_SD870-100C ixus90_sd790-100d S2IS (unknown sub) s3is-100a sx10-101a sx100is-100b sx110is 100b tx1-101b
No failures or crashes have been reported.
The pass/fail in the console only provides a general indication. The logfile should be examined to be sure everything is working.
The log is formatted such that most lines end with OK or ERR followed by possible return values, and then PASS, FAIL, or NA.
- PASS or FAIL indicate whether the test received the result it expected.
- OK and ERR indicate whether the function being tested reported success or failure, which may represent a PASS or FAIL depending on circumstances.
- NA means the script doesn't count the result of that particular call as a pass or fail, because the results are variable or not meaningful.
More informations and a sample log file can be found in reyalp's forum post: preliminary lua iolib and oslib port
Additional Notes: |
- The script also serves as an example of how to use the libraries.
- Since version 0.6.5 / changeset #541 the test script in its latest version is included in the distribution directory CHDK/SCRIPTS/TEST/LLIBTST.LUA in the 'complete' Autobuild download package, it is also available from here.
Some Lua scripts
Additional example scripts are included in the 'complete' CHDK download packages, they are also directly available from CHDK SVN: script examples. |
yet another accurate intervalometer
--[[
rem 20080805
@title yet another accurate intervalometer
@param a Duration (min)/-1 disable
@default a -1
@param b Duration (sec)/n of seqs
@default b 5
@param c Delay 1st sequence (min)
@default c 0
@param d Delay 1st sequence (sec)
@default d 3
@param e Trigger every n min
@default e 0
@param f ...every n sec
@default f 3
@param g ...every .n sec
@default g 0
@param h Endless?
@default h 0
@param i Seq dur (m)/-1
@default i -1
@param j Seq dur (s)/n of shots/seq
@default j 1
]]
drivemode_continuous = 1
if a < -1 then a = -1 end
if ( a > -1 and b < 0 ) then b = 0 end
if ( a == -1 and b < 1 ) then b = 1 end
if c < 0 then c = 0 end
if d < 0 then d = 0 end
if e < 0 then e = 0 end
if f < 0 then f = 0 end
if g < 0 then g = 0 end
if ( h < 0 or h > 1 ) then h = 0 end
if i < -1 then i = -1 end
if ( i > -1 and j < 0 ) then j = 0 end
if ( i == -1 and j < 1 ) then j = 1 end
if (( i == -1 and j > 1 ) or i > -1 ) then
if get_drive_mode() ~= drivemode_continuous then
print( "set drive mode" )
print( "to continuous" )
sleep(1500)
cannot_continue = true
end
end
if a > -1 then duration = a*60000 + b*1000 else duration = b end
delay_first= c*60000 + d*1000
if g < 0 then delay = e*60000 + f*1000 + g*10 else delay = e*60000 + f*1000 + g*100 end
if i > -1 then sequence = i*60000 + j*1000 else sequence = j end
function shoot_by_numbers( sequence_target )
sequence_current = 0
repeat
tick_target = get_tick_count() + delay
sequence_current = sequence_current + 1
print( "sequence " .. sequence_current .. " of " .. sequence_target )
if i == -1 then shoot_count( sequence ) else shoot_tick( sequence ) end
while ( get_tick_count() < tick_target and sequence_current < sequence_target ) do
end
until sequence_current >= sequence_target
end
function shoot_by_duration( duration )
duration_target = get_tick_count() + duration
repeat
tick_target = get_tick_count() + delay
if i == -1 then shoot_count( sequence ) else shoot_tick( sequence ) end
print( (duration_target-get_tick_count())/1000 .. " sec to go" )
while ( get_tick_count() < tick_target and get_tick_count() < duration_target ) do
end
until get_tick_count() >= duration_target
end
function shoot_forever()
tick_initial = get_tick_count()
sequence_current = 0
repeat
tick_target = get_tick_count() + delay
sequence_current = sequence_current + 1
print( "sequence " .. sequence_current )
if i == -1 then shoot_count( sequence ) else shoot_tick( sequence ) end
print ( (get_tick_count()-tick_initial)/1000 .. " sec elapsed")
while ( get_tick_count() < tick_target ) do
end
until false
end
function shoot_count( count_inc )
count_target = get_exp_count() + count_inc
if count_target > 9999 then count_target = count_target - 9999 end
press( "shoot_half" )
press( "shoot_full" )
repeat
until get_exp_count() == count_target
release( "shoot_full" )
repeat
until get_shooting() == false
end
function shoot_tick( tick_duration )
tick_target = get_tick_count() + tick_duration
press( "shoot_half" )
press( "shoot_full" )
while ( get_tick_count() < tick_target ) do
end
release( "shoot_full" )
repeat
until get_shooting() == false
end
if not cannot_continue then
tick_target = get_tick_count() + delay_first
print( "waiting " .. delay_first/1000 .. " sec" )
while ( get_tick_count() < tick_target ) do
tick_current = get_tick_count()
end
if h == 1 then shoot_forever() end
if a > -1 then shoot_by_duration( duration ) else shoot_by_numbers( duration ) end
end
Minimalistic Intervalometer
Often, we want the camera to just take pictures on an interval without being smart about anything. This script was built to fill the need for a very, very simple intervalometer.
This might serve well also as a script for you to read so that you can understand how scripting works. To use: create an empty text file called "mint.lua" in CHDK/SCRIPTS on the flash card. Paste the code below into the file. Start CHDK, press the shortcut key, press Set, select Load Script from File, find mint.lua, go wild.
Should work on any camera and should be very accurate. Enjoy!
--[[
@title Minimalistic Intervalometer
@param a Shooting interval, min
@default a 0
@param b ...sec
@default b 10
--]]
Interval = a*60000 + b*1000
function TakePicture()
press("shoot_half")
repeat sleep(50) until get_shooting() == true
press("shoot_full")
release("shoot_full")
repeat sleep(50) until get_shooting() == false
release "shoot_half"
end
repeat
StartTick = get_tick_count()
TakePicture()
sleep(Interval - (get_tick_count() - StartTick))
until false
Char input demo
This is a demo script in Lua. You can input a text as a folder name, if you want the folder will be created (A/name). In the script parameter menu you can control the keyboard delay for repeating.
It was released by 'msl' in the CHDK forum in this post, a german version is available at www.wirklemms.de
Using the script:
- first consol menu
[<-][->] select a char in 1 step [zoom in/out] select a char in 5 steps [SET] write a char [+/-] delete a char [UP] Selection uppercase, lowercase and special cases [DOWN] return to first char (a) [MENU] ready and go to the second Menu
- second consol menu
display the input
[SET] return to new input [DISP] write the input name as folder and close the script [MENU] close the script
Do not use any illegal folder names - you may lose data or the filesystem could be corrupted ! |
--[[
rem 26-Oct-2008 by msl
@title char input
@param f key delay
@default f 200
]]
key_delay = f
output=""
function button()
local x = 0
repeat
wait_click(key_delay)
if is_pressed "remote" then
key = "REMOTE"
x = 1
end
if is_pressed "set" then
key = "SET"
x = 1
end
if is_pressed "erase" then
key = "ERASE"
x = 1
end
if is_pressed "display" then
key = "DISP."
x = 1
end
if is_pressed "menu" then
key = "MENU"
x = 1
end
if is_pressed "up" then
key = "UP"
x = 1
end
if is_pressed "down" then
key = "DOWN"
x = 1
end
if is_pressed "left" then
key = "LEFT"
x = 1
end
if is_pressed "right" then
key = "RIGHT"
x = 1
end
if is_pressed "zoom_in" then
key = "ZOOM_IN"
x = 1
end
if is_pressed "zoom_out" then
key = "ZOOM_OUT"
x = 1
end
until x == 1
set_led (8,1)
sleep (10)
set_led (8,0)
end
function tabToStr()
output=table.concat(word)
end
function input()
abc_lower = {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p",
"q","r","s","t","u","v","w","x","y","z"}
abc_upper = {"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P",
"Q","R","S","T","U","V","W","X","Y","Z"}
abc_spec = {"0","1","2","3","4","5","6","7","8","9",",",".","-",";",":","_",
"/",".JPG",".CRW",".CR2",".THM",".WAV",".LUA",".BAS",".TXT"," "}
word = {}
a=0
b=0
actChar=""
repeat
print("[<-][->][SET] [+/-][MENU]")
print("[ZOOM in/out] [UP][DOWN]")
button()
cls()
if key == "RIGHT" then a=a+1 end
if key == "LEFT" then a=a-1 end
if key == "UP" then b=b+1 end
if key == "DOWN" then a=1 end
if key == "ZOOM_IN" then a=a+5 end
if key == "ZOOM_OUT" then a=a-5 end
if a >= 27 then a=1 end
if a <= 0 then a=26 end
if b>=3 then b=0 end
if b==0 then
actChar=abc_lower[a]
char_info="lower case"
end
if b==1 then
actChar=abc_upper[a]
char_info="upper case"
end
if b==2 then
actChar=abc_spec[a]
char_info="special char"
end
print(char_info..": "..actChar)
if key == "SET" then table.insert(word,actChar) end
if key == "ERASE" then table.remove(word) end
tabToStr()
print("input: "..output)
print (" ")
until key == "MENU"
end
function make_dir(dirname)
os.mkdir(dirname)
end
x=0
repeat
input()
cls()
print("INPUT: "..output)
print("[SET] new input")
print("[DISP] make dir and stop")
print("[MENU] stop")
button()
if key == "SET" then cls() end
if key == "DISP." then
dir = "A/"..output
make_dir(dir)
print "ready"
sleep(3000)
x=1
end
if key == "MENU" then
print "ready"
sleep(3000)
x=1
end
until x==1
--[[
***possible commands***
function make_dir(dirname)
os.mkdir(dirname)
end
function delete_dir(dirname)
os.remove(dirname)
end
function rename_file(old_filename, new_filename)
os.rename(old_filename, new_filename)
end
function delete_file(filename)
os.remove(filename)
end
***missing commands***
-os.list_dir
]]
Universal Tv mode
This is a script for a enhanced tv mode. It should work with all cameras, even with models with or without tv mode.
It was released by 'msl' in the CHDK forum in this post,a german version is available at www.wirklemms.de
- You can select a Tv value from 64s to 1/10000s
- The zoom can be used while running the script
- You can select a focus mode
- Continuous shooting is also possible
Using the script:
- The console menu:
[<-][->] select a Tv value [UP][DOWN] zooming [DISP.] select a focus mode [SET][Remote] shooting [MENU] exit
In the script parameter menu you can adjust the start Tv value, the key delay and the shoot delay.
--[[
rem 26-Oct-2008 by msl
@title Tv mode universal
@param a integer value [Tv]
@default a 0
@param b key delay [ms]
@default b 80
@param c shoot delay [s]
@default c 0
]]
function print_Tv()
tv_output = {"64s","50s","40s","32s","25s","20s","15s","13s","10s","8s","6s",
"5s","4s","3.2s","2.5s","2s","1.6s","1.3s","1s","0.8s","0.6s","0.5s","0.4s",
"0.3s","1/4s","1/5s","1/6s","1/8s","1/10s","1/13s","1/15s","1/20s","1/25s",
"1/30s","1/40s","1/50s","1/60s","1/80s","1/100s","1/125s","1/160s","1/200s",
"1/250s","1/320s","1/400s","1/500s","1/640s","1/800s","1/1000s","1/1250s",
"1/1600s","1/2000s","1/2500s","1/3200s","1/4000s","1/5000s","1/6400s",
"1/8000s","1/10000s"}
print_tv = "Tv : "..tv_output[tv_input+19]
end
function mf_mode()
mf_output = {"normal","macro","","infinite"}
print_mf = "focus: "..mf_output[mf_input]
end
function button()
local x = 0
repeat
wait_click(key_delay)
if is_pressed "remote" then
key = "SET"
x = 1
end
if is_pressed "set" then
key = "SET"
x = 1
end
if is_pressed "menu" then
key = "MENU"
x = 1
end
if is_pressed "display" then
key = "DISP"
x = 1
end
if is_pressed "left" then
key = "LEFT"
x = 1
end
if is_pressed "right" then
key = "RIGHT"
x = 1
end
if is_pressed "up" then
key = "UP"
x = 1
end
if is_pressed "down" then
key = "DOWN"
x = 1
end
until x == 1
set_led (8,1)
sleep (10)
set_led (8,0)
end
--script start
if a < -18 then a = -18 end
if a > 40 then a = 40 end
if b < 50 then b = 50 end
if c < 0 then c = 0 end
tv_input = a
key_delay = b
shoot_delay = c
max_zoom = get_zoom_steps()
zoom = get_zoom()
repeat
if get_propset() == 2 then
mf_input = get_prop(6)+1
else
mf_input = get_prop(11)+1
end
cls()
print_Tv()
mf_mode()
print("[<-][->] ",print_tv)
print("[Up][Down] zoom:",zoom.."/".. max_zoom)
print("[DISP.] ",print_mf)
print("[SET] [Remote] shoot")
print("[MENU] exit")
button()
if key == "DISP" then
mf_input = mf_input + 1
if mf_input == 3 then mf_input = 4 end
if mf_input == 5 then mf_input = 1 end
if get_propset() == 2 then
set_prop(6,mf_input-1)
else
set_prop(11,mf_input-1)
end
end
if mf_input == 2 then
set_zoom(0)
else
if key == "UP" then
zoom = zoom + 1
if zoom > max_zoom then zoom = max_zoom end
set_zoom(zoom)
end
if key == "DOWN" then
zoom = zoom - 1
if zoom < 0 then zoom = 0 end
set_zoom(zoom)
end
end
if key == "RIGHT" then tv_input = tv_input + 1 end
if key == "LEFT" then tv_input = tv_input - 1 end
if tv_input > 40 then tv_input = -18 end
if tv_input < -18 then tv_input = 40 end
if key == "SET" then
if shoot_delay > 0 then
cls()
print("wait "..shoot_delay.." s")
sleep(shoot_delay * 1000)
end
TV = tv_input * 32
press "shoot_half"
repeat
until get_shooting() == true
if get_propset() == 2 then
set_prop(262,TV)
else
set_prop(69,TV)
end
press "shoot_full"
release "shoot_full"
release "shoot_half"
end
until key == "MENU"
Listdir sample
This scripts demonstrates the usage of os.listdir
, scroll down the list with any key...
--[[
@title Listdir
rem 10-11-2008 by msl
--]]
dir = os.listdir("A/CHDK", true) --'true' shows also . and ..
count = table.getn(dir)
x = 0
for i=1, count do
print(i..".",dir[i])
x = x + 1
if x == 4 then
wait_click(0)
x = 0
end
end
print("------------") -- end of the list
sleep(3000)
wait_click(0)
Lotto demo
This script is a little mathematical demo.
--Example lua script that generates random numbers in various ways.
--idea & code by PhyrePhoX and msl
--[[
@title lotto demo
@param n how many
@default n 6
@param r max
@default r 49
@param s min
@default s 1
@param e exclusive 1=on
@default e 1
@param o sort
@default o 1
@param z sound 1=on
@default z 1
]]
--The comment block above will be read as parameters.
--Declare a function for key request with led and sound feedback
function button() -- declare function
local x = 0 -- local variable only valid for this function
repeat -- start loop
wait_click(150) -- wait for key klick
if is_pressed "set" then -- check which key ist pressed
key = "SET"
x = 1
end
if is_pressed "menu" then
key = "MENU"
x = 1
end
until x == 1 -- end of loop
set_led (8,1) -- led feedback
sleep (10)
set_led (8,0)
if sound == 1 then play_sound(4) end -- sound feedback if set
end
--Start script
--Declare usefull variable names for the parameter variables
count = n
min = s
max = r
exclusive = e
order = o
sound = z
--Check parameters, if wrong ending the script
if (min >= max) then
print("Wrong params, dumbass!;-)")
wait_click(0)
else
if ((exclusive == 1) and ((max - min + 1)<count)) then
print("Wrong params, dumbass!;-)")
wait_click(0)
else
--If parameters ok start the main loop to dice
repeat
result= {} -- create a table for result
if exclusive == 1 then -- if exclusive is set
array = {} -- create a table for mix
for i = min, max do -- loop for fill the table
array[i] = i
end
for i = min, max do -- loop for mix the table
rnd = math.random(min, max) -- create a random number
buffer = array[i] -- change a number in the table
array[i] = array[rnd]
array[rnd] = buffer
end
for c=1, count do -- loop for output the result
result[c] = array[c]
end
else
for i = min, max do -- loop for no exclusive result
result[i] = math.random(min, max)-- create a random number
end
end
--Output the result
if order == 1 then table.sort(result) end -- order result if set
output = table.concat(result,", ") -- create a string of the table
print("dice [SET] end [MENU]") -- output in console
print()
print(output) -- print a string variable
button() -- call the function
cls() -- clear the console
until key == "MENU" -- end of loop if pressed "MENU"
end -- "SET" repeat the loop
end
--All functions, conditions and loops (except repeat) will closing with end
TagMe, the Lua EXIF tagger
- Autor: Stefan Dittforth ("stift")
- Published: 06-Sept-2009 in the german forum
- Forum links: German forum, International forum
This script allows a user to select a text from a configurable list of text strings and write this string into the EXIF UserComment tag for a list of images
- The functions for reading and modifying the EXIF information are in a seperate module EXIF.lua which can be imported and reused in other scripts
- The script is excellent commented, the download package also includes a very good user's guide
- There are lots of useful functions and informations in the script and the exif module
- It nicely demonstrates advanced Lua programming technics
- → The download package, including the script, the exif lib and the documentation (in english & german) is available from here
RAW development
Since CHDK version 0.8.4 there are some new commands to merge/develop RAW images directly in the camera, read Lua Reference: RAW development for more informations.
There's also a script to demonstrate the usage of this new feature: Lua Reference: Sample test script