Fake key presses using XHB

Question

I'm trying to simulate key presses using XHB and XTest, using this example code as a reference. Unfortunately, whatever I do, the resulting program has no effect. No exceptions, no warnings.

Any ideas?

I'm using XHB 0.5.2012.11.23 with GHC 7.4.1 on Ubuntu 12.04.

Here's what I've got so far:

import Control.Monad
import Control.Concurrent
import Graphics.XHB
import Graphics.XHB.Gen.Test

main = do
    Just c <- connect
    let keyCode = 38  -- A
    forever $ do
        fakeInput c $ MkFakeInput (toBit' EventMaskKeyPress) keyCode 0 (fromXid xidNone) 0 0 0
        threadDelay $ 1 * 1000
        fakeInput c $ MkFakeInput (toBit' EventMaskKeyRelease) keyCode 0 (fromXid xidNone) 0 0 0
        threadDelay $ 1 * 1000

toBit' :: (BitEnum a, Integral b) => a -> b
toBit' = fromIntegral . toBit

Answer 1

The issue here is a bit subtle. If you look at the XTest protocol you'll find that the FAKE_EVENT doesn't expect an EVENT_MASK but instead expects a FAKE_EVENT_TYPE. KeyPress is FAKE_EVENT_TYPE 2 whereas KeyRelease is 3. Things work as expected after these values are used in place of EventMaskKeyPress and EventMaskKeyRelease (moreover, you don't need the nasty toBit coercion, which was the smell that pointed me towards this being incorrect).