Pull Key Events And Run Shell Concurrently

Hi,

I'm currently writing the submission program for my app store (see signature for more info). I'm at a stage where I'd like to take screenshots of the computer screen. I know I can't directly access the 'pixels', but I'll be changing term.write to also write to a table. My problem is, however, trying to capture a key press to fire the screenshot, yet run the shell and another program at the same time. I need to be able to use the shell because some of the programs may be shell based and I'd rather not fake it using read() or a similar process. When ever I try something such as the following only 'Test fired!' is displayed. This may be due to the coroutine.yeild() that is being called. I may not be explaining myself amazingly well, but essentially I'm trying to capture key presses while the shell is running. If you can think of a better way of doing it let me know. Thanks :)/>

function pull()
  while true do
	event = os.pullEvent()
	print(event .. ' was fired!')
  end
end
function test()
  print('Test fired!')
end

parallel.waitForAny(pull, test)

Ok so judging off what you said, you're wanting to capture a screenshot when a certain key is pressed.

The way you're doing it is right in principle, here is a test that I've done…. Press F2 and you'll see that it works…

local function runShell()
  os.run({}, "rom/programs/shell")
end

--# this just shows that it was pressed, the real work is done in the function below
local function printTopLine(msg)
  local sx,sy = term.getCursorPos()
  term.setCursorPos(1, 1)
  term.clearLine()
  term.setTextColor(colors.yellow)
  write(msg)
  term.setTextColor(colors.white)
  term.setCursorPos(sx,sy)
end

local function listenForKey()
  local timeout

  while true do
	local e, p = os.pullEventRaw()
	if e == "key" and p == keys.f2 then
	  printTopLine("Screenshot key pressed...")
	  timeout = os.startTimer(2)
	elseif e == "timer" and p == timeout then
	  printTopLine(os.version())
	end
  end
end

term.clear()
term.setCursorPos(1, 1)
parallel.waitForAll(runShell, listenForKey)

theoriginalbit, on 23 August 2013 - 09:24 AM said:

Ok so judging off what you said, you're wanting to capture a screenshot when a certain key is pressed.

The way you're doing it is right, here is a test that I've done…. Press F2 and you'll see that it works…

local function runShell()
  os.run({}, "rom/programs/shell")
end

--# this just shows that it was pressed, the real work is done in the function below
local function printTopLine(msg)
  local sx,sy = term.getCursorPos()
  term.setCursorPos(1, 1)
  term.clearLine()
  term.setTextColor(colors.yellow)
  write(msg)
  term.setTextColor(colors.white)
  term.setCursorPos(sx,sy)
end

local function listenForKey()
  local timeout

  while true do
	local e, p = os.pullEventRaw()
	if e == "key" and p == keys.f2 then
	  printTopLine("Screenshot key pressed...")
	  timeout = os.startTimer(2)
	elseif e == "timer" and p == timeout then
	  printTopLine(os.version())
	end
  end
end

term.clear()
term.setCursorPos(1, 1)
parallel.waitForAll(runShell, listenForKey)

Ah, I see. Running shell as a program, didn't really think about that. I haven't really got time to test it now but it looks sound, thanks! :D/>

the issue with the code you originally posted was that test printed and immediately exited, which would cause both coroutines to exit immediately with parallel.waitForAny.

Which means parallel.waitForAll is needed.

The reason I used waitForAny is because I thought that it when the test function was run the shell would resume, leaving the key capture still running. theoriginalbit's method worked almost perfectly, I just had to pass the current instance of the shell so it wouldn't run startup.