I will go straight to the point.
This can be done here: 
But I want to capture what I see on screen using a function and then save the image in Documents and then display it.
Function should look like this:
image = ScreenCapture(x,y,w,h or null for fullscreen)
saveImage("Documents:ScreenCapture", image)
Well, firstly Simeon has a couple tutorials available that cover this. They should be visible in your project viewer by way of update. If you have not updated your Codea on your ipad i suggest you do so now.
Alternatively heres my stab at putting together something along those lines:
-- imagcon Toggle 2
--clearProjectData()
-- Use this function to perform your initial setup
function setup()
setInstructionLimit(0)
--[[
if you want to manually select
and delete some images go here
readImage()
Otherwise you can select an image from your Documents folder
by Default while running this program through the Your_Current_Image
--]]
Instructions_and_Results()
alpha = 255 --sets the capture area's alpha channel
--so you can see it before capture
--it turns invisible when you make a capture
bga = alpha --sets the BackGround Alpha
--so you can see the background color
--you will be given the option
--to remove it or not
Capwidth = 200
Capheight = Capwidth
Imgwidth = 200
spritex = Capwidth/2
spritey = spritex
Your_Current_Image = 1
dynameters()
end
function Instructions_and_Results()
capnum = nil
screencaps = 0
imagcaps = 0
imgnum = nil
fontbga = 255
buttonbga = 255
print("ImagCon-T"..RETURN)
for screens,cap in pairs(spriteList("Documents")) do
if imgnum == nil then
imgnum = 1
if Images == nil then Images = {"Documents:"..cap} end
Images[imgnum] = "Documents:"..cap
else
imgnum = imgnum + 1
if Images[imgnum] == nil then Images[imgnum] = "Documents:"..cap end
end
if capnum == nil and string.sub(cap,7,9) == "Cap" then
capnum = 1
print(cap)
elseif string.sub(cap,7,9) == "Cap" then
capnum = capnum + 1
print(cap)
end --if
if string.sub(cap,1,9) == "ImagCnCap" then
if imagcaps == 0 then
imagcaps = 1
else
imagcaps = imagcaps + 1
end --if
end --if
if string.sub(cap,1,9) == "ScreenCap" then
if screencaps == 0 then
screencaps = 1
else
screencaps = screencaps + 1
end --
end
end
if capnum == nil then
Capturetotal = "There are no Captures at this time"..RETURN
elseif capnum == 1 then
Capturetotal =" Capture total"
elseif capnum > 1 then
Capturetotal = " Captures total"
end --if
if capnum ~= nil then
print(RETURN..tostring(capnum)..Capturetotal)
else
print(RETURN..Capturetotal)
end --if
if screencaps > 0 then
if screencaps == 1 then
totalscreencaps = " Screen Capture total"
elseif screencaps > 1 then
totalscreencaps = " Screen Captures total"
end --if
print(tostring(screencaps)..totalscreencaps)
end
print("You have "..tostring(imgnum).." images Available in your Documents folder")
print(RETURN.."Instructions:"..RETURN.."Make sure your image"..RETURN.."is inside the box to capture it "..RETURN.."(the image not the box)"..RETURN..RETURN.."For ScreenCaps:"..RETURN.."Make sure your CapHeight is set to 1024"..RETURN.."and your CapWidth is set to 768 for Fullscreen and full standard caps. "..RETURN..RETURN.."Anything less than those dimensions will not capture the entire screen."..RETURN..RETURN.."So it won't be saved as a Screencap. Instead it will be saved as ImagCnCap"..RETURN..RETURN.."Last but not least tap twice to the right of the parameters anywhere on the screen to the right to capture. Enjoy!")
end
function dynameters()
iparameter("Capwidth",16,768,Capwidth)
iparameter("Capheight",16,HEIGHT,Capheight)
iparameter("Imgwidth",16,WIDTH,Imgwidth)
iparameter("spritex",0,WIDTH,spritex)
iparameter("spritey",0,HEIGHT,spritey)
-- iparameter("wrapwidth",0,WIDTH,100)
iparameter("Your_Current_Image",1,#Images,Your_Current_Image)
if fieldbackup == nil then
fieldbackup = {Capwidth}
fieldbackup[2] = Capheight
fieldbackup[3] = Imgwidth
fieldbackup[4] = spritex
fieldbackup[5] = spritey
fieldbackup[6] = Your_Current_Image
loadedsprite = readImage(Images[Your_Current_Image])
end
end
function draw()
-- This sets a dark background color
if bga == 255 then
background(40, 40, 50,bga)
else
background(0,0,0,bga)
end
-- This sets the line thickness
strokeWidth(1)
stroke(255,alpha)
noFill()
rect(0,0,Capwidth,Capheight)
noStroke()
fill(0,0,255,buttonbga)
rect(125,497,25,12.5)
fill(255,0,0,buttonbga)
rect(179,499,17,9)
--500
fill(0, 0, 0, buttonbga)
rect(125,542.9,87,15)
rect(232.886,542.9,72,15)
-- Do your drawing here
font("Courier")
fontSize(13)
buttonbga = fontbga
fill(255,fontbga)
textWrapWidth(242)
text("Capture the background as well? ",172,527)
text("Yes",139,502) --497)
text("No",188,503) --510
font("Courier")
fontSize(13)
fill(255,fontbga)
textWrapWidth(181)
text("Fullscreen or Standard?",219,551)
if show == "full" then
displayMode(FULLSCREEN)
show = ""
elseif show == "stand" then
displayMode(STANDARD)
show = ""
end
if Your_Current_Image ~= fieldbackup[6] then
fieldbackup[1] = Capwidth
fieldbackup[2] = Capheight
fieldbackup[3] = Imgwidth
fieldbackup[4] = spritex
fieldbackup[5] = spritey
fieldbackup[6] = Your_Current_Image
clearParameters()
Capwidth = fieldbackup[1]
Capheight = fieldbackup[2]
width = fieldbackup[3]
spritex = fieldbackup[4]
spritey = fieldbackup[5]
Your_Current_Image = fieldbackup[6]
loadedsprite = readImage(Images[Your_Current_Image])
clearOutput()
dynameters()
Instructions_and_Results()
print("loaded")
end
if spritex > Capwidth or spritex < 0 then
fieldbackup[1] = Capwidth
fieldbackup[2] = Capheight
fieldbackup[3] = Imgwidth
fieldbackup[4] = spritex
fieldbackup[5] = spritey
fieldbackup[6] = Your_Current_Image
clearParameters()
Capwidth = fieldbackup[1]
Capheight = fieldbackup[2]
width = fieldbackup[3]
spritex = Capwidth/2
fieldbackup[4] = spritex
spritey = fieldbackup[5]
Your_Current_Image = fieldbackup[6]
dynameters()
end
if spritey > Capheight or spritey < 0 then
fieldbackup[1] = Capwidth
fieldbackup[2] = Capheight
fieldbackup[3] = Imgwidth
fieldbackup[4] = spritex
fieldbackup[5] = spritey
fieldbackup[6] = Your_Current_Image
clearParameters()
Capwidth = fieldbackup[1]
Capheight = fieldbackup[2]
width = fieldbackup[3]
spritex = fieldbackup[4]
spritey = Capheight/2
fieldbackup[5] = spritey
Your_Current_Image = fieldbackup[6]
dynameters()
end
sprite(loadedsprite,spritex,spritey,Imgwidth)
if andanother == "y" then
alpha = 0
if omitbg == "n" then
bga = 0
elseif omitbg == "y" then
bga = 255
end
fontbga = alpha
buttonbga = fontbga
clearOutput()
andanother = ""
SaveCap()
end
end
function touched(touch)
--touch based omission
if touch.x > 0 and touch.x < Capwidth + 1 and touch.y < Capheight + 1 and touch.y > 0 and savedCap ~= nil then
savedCap:set(touch.x,touch.y,0,0,0,0)
end
if touch.x >= 125 and touch.x <=125 + 87 and touch.y >= 542.9 and touch.y <= 542.9 + 15 then
show = "full"
elseif touch.x >= 232.886 and touch.x <= 232.886 + 72 and touch.y >= 542.9 and touch.y <= 542.9 + 15 then
show = "stand"
end
if touch.x > -1 and touch.tapCount == 2 then
if touch.state == BEGAN or touch.state == MOVING then
fontbga = 255
--elseif touch.state == ENDED then
--fontbga = 0
buttonbga = fontbga
end
if touch.x >= 125 and touch.x <= 125 + 25 and touch.y >= 497 and touch.y <= 497 + 12.5 then
omitbg = "y"
andanother = "y"
elseif touch.x >= 179 and touch.x <= 179 + 17 and touch.y >= 499 and touch.y <= 499 + 9 then
omitbg = "n"
andanother = "y"
end
end
end
--[[
fill(0,0,255,buttonbga)
rect(125,497,25,12.5)
fill(255,0,0,buttonbga)
rect(179,500,17,8.5)
--]]
function SaveCap()
if Capwidth == 768 and Capheight == 1024 then
if scrncp == nil then scrncp = 1 + screencaps else scrncp = scrncp + 1 end
savor = "Documents:ScreenCap"..tostring(scrncp)
elseif Capwidth == Capheight or Capwidth < 768 or Capheight < 1024 then
if imgcp == nil then imgcp = 1 + imagcaps else imgcp = imgcp + 1 end
savor = "Documents:ImagCnCap"..tostring(imgcp)
end
--ImagCnCap
savedCap = image(Capwidth,Capheight)
setContext(savedCap)
draw()
setContext()
saveImage(savor,savedCap)
alpha = 255
bga = alpha
show = "stand"
Instructions_and_Results()
print("saved")
end
Description = "ImagCon Guys this is it a way to capture, resize, and save what's on your screen. As well as a way to move, resize, capture, and save images you have in your spritepacks be it in your Documents folders or your camera roll . "..RETURN.."Special thanks to Simeon for the ScreenCap tutorial, without which none of this would be possible. As well as his image IO tutorial."
saveProjectInfo("Description",Description)
saveProjectInfo("Author","melrdmydea")
oh and incase you’re wondering it works. I’ve used it myself.
As for displaying it in one of your programs?
you’ll want to code in a sprite() function with a reference to the name of the image.
just code in sprite() then touch inside those () and you should bring up your spritepack. Go to documents and look for either ImagCnCap or ScreenCap. touch it and it will be assigned to that sprite
@mpilgrem, I tried this idea, but the screen goes black.
It would be great if the items would remain on the screen during capture.
Here’s the code:
function setup()
displayMode(FULLSCREEN)
end
function draw()
myImage = image(WIDTH, HEIGHT)
setContext(myImage)
background(40, 40, 50)
if CurrentTouch.state == BEGAN then
fill(16, 178, 197, 255)
elseif CurrentTouch.state == MOVING then
fill(255, 0, 0, 255)
elseif CurrentTouch.state == ENDED then
fill(210, 218, 16, 255)
end
ellipse(CurrentTouch.x, CurrentTouch.y, 100,100)
setContext()
if CurrentTouch.state == BEGAN then
saveImage("Documents:ScreenCapture", myImage)
end
end
I tried to duplicate code to display on the screen what is happening, but Codea was locked and closed.
Here’s the code:
function setup()
displayMode(FULLSCREEN)
end
function draw()
myImage = image(WIDTH, HEIGHT)
setContext(myImage)
background(40, 40, 50)
if CurrentTouch.state == BEGAN then
fill(16, 178, 197, 255)
elseif CurrentTouch.state == MOVING then
fill(255, 0, 0, 255)
elseif CurrentTouch.state == ENDED then
fill(210, 218, 16, 255)
end
ellipse(CurrentTouch.x, CurrentTouch.y, 100,100)
setContext()
if CurrentTouch.state == BEGAN then
saveImage("Documents:ScreenCapture", myImage)
end
background(40, 40, 50)
if CurrentTouch.state == BEGAN then
fill(16, 178, 197, 255)
elseif CurrentTouch.state == MOVING then
fill(255, 0, 0, 255)
elseif CurrentTouch.state == ENDED then
fill(210, 218, 16, 255)
end
ellipse(CurrentTouch.x, CurrentTouch.y, 100,100)
end
Maybe I didn’t explain exactly.
I want to capture what is happening on the screen on the fly.
@Georgian did you even look at my code? The screen should not be going black if its my code youre referring to.
Also my code does work on the fly.
Also Georgian after about 4 sec your’s crashes. You need a conditional statement to stop the capture.
@melrdmydea , I’ll try your code, but it’s a BIG code 8-| I like small codes / solutions.
Thanks melrdmydea for help!
Finally, I think that would be great if there were a similar function for capture screen image like startRecording()
I like @mpilgrem solution. Its very short and simple. But is there any possibility to save the picture in the standard picture folder of the iPad? I would like to use that for my Fractal program. My last solution would be to call ObjectiveC code when creating the final ipa. I just need to get the LUA image moved to ObjectiveC… I think 
@Georgian: In your sample you only render to the image and not on the screen. If you only want to save while touched, then use it like @mpilfgrem to set context and then call draw from outside. If you really want to save the frame and see it on the screen, then just render the image. In your example above, just add this to your code after setContext():
...
spriteMode(CORNER)
sprite(myImage, 0, 0)
But it will be much slower to always render in an image and then render the image… i needed that, but it didnt work fast enough.