Global keyboard hook

[Shardik]

Is it possible to create a global keyboard hook for a mac application?

The simplest solution is to use the HotKey API functions of Carbon. Unfortunately there doesn't exist a comparably simple and efficient Cocoa API solution. Most Cocoa examples simply wrap the Carbon API functions. Therefore I have done the same in the following example which I tested successfully on Mac 10.6.8 (Snow Leopard) and 10.8.2 (Mountain Lion) with Cocoa x86 and x64 and subsystem Carbon in both ASCII and Unicode mode.

The example code starts an invisible window and waits for the hot key combination Shift+Control+Space. When detected it makes the window visible. You may define several different hot keys which are handled in the HotKeyHandler() callback. The 4 byte signature of a hot key is user-defined and may be changed at will.

Code: Select all

EnableExplicit

#kEventClassKeyboard = $6B657962     ; 'keyb'
#kEventHotKeyPressed = 5
#kEventParamDirectObject = $2D2D2D2D ; '----'
#typeEventHotKeyID = $686B6964       ; 'hkid'

#controlKeyBit = 12
#controlKey = 1 << #controlKeyBit
#shiftKeyBit = 9
#shiftKey = 1 << #shiftKeyBit

ImportC ""
  GetApplicationEventTarget()
  RegisterEventHotKey(HotKeyCode.L, HotKeyModifiers.L, HotKeyID.Q, EventTargetRef.I, OptionBits.L, *EventHotKeyRef)
  UnregisterEventHotKey(EventHotKeyRef.I)
EndImport

Structure EventTypeSpec
  EventClass.L
  EventKind.L
EndStructure

Structure EventHotKeyID
  Signature.L
  ID.L
EndStructure

ProcedureC HotKeyHandler(NextHandlerRef.I, EventRef.I, *UserData)
  Protected HotKey.Q
  If GetEventParameter_(EventRef, #kEventParamDirectObject, #typeEventHotKeyID, 0, SizeOf(EventHotKeyID), 0, @HotKey) = 0
    If PeekL(HotKey) = $68746B31 ; HotKey\Signature = 'htk1' ?
      If PeekL(HotKey + 4) = 1   ; HotKey\ID = 1 ?
        HideWindow(0, #False)
      EndIf
    EndIf
  EndIf
EndProcedure

Define HotKey.EventHotKeyID
Define HotKeyRef.I

Dim EventTypes.EventTypeSpec(0)

EventTypes(0)\EventClass = #kEventClassKeyboard
EventTypes(0)\EventKind = #kEventHotKeyPressed

HotKey\Signature = $68746B31 ; 'htk1'
HotKey\ID = 1

OpenWindow(0, 270, 100, 220, 70, "Activated by HotKey", #PB_Window_SystemMenu | #PB_Window_Invisible)

; ----- Install EventHandler to react to pressing of hot key(s)
If InstallEventHandler_(GetApplicationEventTarget(), @HotKeyHandler(), 1, @EventTypes(), 0, 0) = 0
  ; ----- Register hot key (Control+Shift+Space)
  RegisterEventHotKey(49, #controlKey | #shiftKey, @HotKey, GetApplicationEventTarget(), 0, @HotKeyRef)
EndIf

Repeat
Until WaitWindowEvent() = #PB_Event_CloseWindow

; ----- You do not need to unregister a hot key when your application
;       terminates; the system takes care of that for you. You can use this
;       function if the user changes a hot key for something in your
;       application - you would unregister the previous key and register your
;       new key.
UnregisterEventHotKey(HotKeyRef)

[spacebuddy]

Thanks Shardik, it works perfectly

[nikoniko]

I found JNativeHook java library http://code.google.com/p/jnativehook/
Is it really set global hook under MacOSX?

[Shardik]

I found JNativeHook java library http://code.google.com/p/jnativehook/

Thank you for your interesting link! I downloaded the sourcecode of JNativeHook and took a look into /JNativeHook/src/native/osx/NativeThread.c. They used the API functions CGEventMaskBit() to setup the event mask to listen for and CGEventTapCreate() (just like wilbert had proposed).

Is it really set global hook under MacOSX?

Yes, JNativeHook sets up a global hook, just like my PureBasic example which is much simpler by using higher level Carbon API functions to reduce the lines of code you have to use...

[Andre]

@shardik: your example works well on MacOS 10.5.8 too, thank you!

[nikoniko]

Yes, JNativeHook sets up a global hook, just like my PureBasic example which is much simpler by using higher level Carbon API functions to reduce the lines of code you have to use...

Your example is simple but doesn't track all keystrokes (ok, most of them).

It is useful for advanced tool to capture ctrl, shift, etc keys.

[nikoniko]

Seems it isn't hard for macosx guru, but not for me yet.

Add 2 links (use this topic as bookmark)

Log keydowns and mouse buttons
http://forums.appleinsider.com/t/7872/k ... r-mac-os-x

Receiving, Filtering, and Modifying Mouse Events
http://www.osxbook.com/book/bonus/chapter2/altermouse/
And key events
http://www.osxbook.com/book/bonus/chapter2/alterkeys/

[wilbert]

Did you see this post ?
http://www.purebasic.fr/english/viewtop ... 25#p411225

[wilbert]

Code: Select all

EnableExplicit

#KeyDownMask      = 1 << 10
#KeyUpMask        = 1 << 11
#FlagsChangedMask = 1 << 12

#kCGKeyboardEventKeycode = 9

ImportC ""
  CGEventTapCreate(tap, place, options, eventsOfInterest.q, callback, refcon)
  CGEventGetIntegerValueField.q(event, field)
  CGEventKeyboardGetUnicodeString(event, maxStringLength, *actualStringLength, *unicodeString)
EndImport

Define eventTap

ProcedureC eventTapFunction(proxy, type, event, refcon)
  Protected keyCode = CGEventGetIntegerValueField(event, #kCGKeyboardEventKeycode)
  Protected unicodeBuffer.q, bufferLen.i = 4
  CGEventKeyboardGetUnicodeString(event, bufferLen, @bufferLen, @unicodeBuffer)
  Protected text.s = PeekS(@unicodeBuffer, bufferLen, #PB_Unicode)
  
  SetGadgetText(0, "keyCode : " + Str(keyCode) + #LF$ + "String : " + text)
EndProcedure


If OpenWindow(0, 0, 0, 220, 70, "keyCode tap", #PB_Window_SystemMenu | #PB_Window_ScreenCentered)
  StickyWindow(0, 1)
  StringGadget(0, 10, 10, 200, 50, "")
  
  eventTap = CGEventTapCreate(0, 0, 1, #KeyDownMask | #FlagsChangedMask, @eventTapFunction(), 0)
  If eventTap
    CocoaMessage(0, CocoaMessage(0, 0, "NSRunLoop currentRunLoop"), "addPort:", eventTap, "forMode:$", @"kCFRunLoopDefaultMode")
  EndIf

  Repeat : Until WaitWindowEvent() = #PB_Event_CloseWindow
EndIf

[nikoniko]

Wilbert +100

While I am writing reply about my attempts to change your code for all processes and flags keys you are posting fully working code for me.

Thanks, thanks, thanks.

[wilbert]

Here's a modification also showing the keyboard related flags

Code: Select all

EnableExplicit

#KeyDownMask      = 1 << 10
#KeyUpMask        = 1 << 11
#FlagsChangedMask = 1 << 12

#kCGKeyboardEventKeycode = 9

ImportC ""
  CGEventTapCreate(tap, place, options, eventsOfInterest.q, callback, refcon)
  CGEventGetFlags.q(event)
  CGEventGetIntegerValueField.q(event, field)
  CGEventKeyboardGetUnicodeString(event, maxStringLength, *actualStringLength, *unicodeString)
EndImport

Define eventTap

ProcedureC eventTapFunction(proxy, type, event, refcon)
  Protected keyCode = CGEventGetIntegerValueField(event, #kCGKeyboardEventKeycode)
  Protected keyFlags = CGEventGetFlags(event) >> 16 & 255
  Protected unicodeBuffer.q, bufferLen.i = 4
  CGEventKeyboardGetUnicodeString(event, bufferLen, @bufferLen, @unicodeBuffer)
  Protected text.s = PeekS(@unicodeBuffer, bufferLen, #PB_Unicode)
  
  SetGadgetText(0, "keyCode : " + Str(keyCode) + #LF$ + "keyFlags : " + RSet(Bin(keyFlags), 8, "0") + #LF$ + "string : " + text)
EndProcedure


If OpenWindow(0, 0, 0, 220, 90, "keyCode tap", #PB_Window_SystemMenu | #PB_Window_ScreenCentered)
  StickyWindow(0, 1)
  StringGadget(0, 10, 10, 200, 70, "")
  
  eventTap = CGEventTapCreate(0, 0, 1, #KeyDownMask | #FlagsChangedMask, @eventTapFunction(), 0)
  If eventTap
    CocoaMessage(0, CocoaMessage(0, 0, "NSRunLoop currentRunLoop"), "addPort:", eventTap, "forMode:$", @"kCFRunLoopDefaultMode")
  EndIf

  Repeat : Until WaitWindowEvent() = #PB_Event_CloseWindow
EndIf

And a practical example of responding to the key combination [fn] + [esc]

Code: Select all

EnableExplicit

#KeyDownMask      = 1 << 10
#FlagsChangedMask = 1 << 12

#kCGKeyboardEventKeycode = 9

ImportC ""
  CGEventTapCreate(tap, place, options, eventsOfInterest.q, callback, refcon)
  CGEventGetFlags.q(event)
  CGEventGetIntegerValueField.q(event, field)
EndImport

Define eventTap


Global SpeechSynthesizer = CocoaMessage(0, CocoaMessage(0, 0, "NSSpeechSynthesizer alloc"), "initWithVoice:", #nil)

ProcedureC eventTapFunction(proxy, type, event, refcon)
  Protected keyCode = CGEventGetIntegerValueField(event, #kCGKeyboardEventKeycode)
  Protected keyFlags = CGEventGetFlags(event) >> 16 & 255
  
  If keyCode = 53 And keyFlags & $80
    ; [fn] + [esc] pressed
    CocoaMessage(0, SpeechSynthesizer, "startSpeakingString:$", @"fn and esc pressed")
  EndIf
  
EndProcedure


If OpenWindow(0, 0, 0, 200, 30, "key tap", #PB_Window_SystemMenu | #PB_Window_Minimize | #PB_Window_NoActivate)
  
  eventTap = CGEventTapCreate(0, 0, 1, #KeyDownMask | #FlagsChangedMask, @eventTapFunction(), 0)
  If eventTap
    CocoaMessage(0, CocoaMessage(0, 0, "NSRunLoop currentRunLoop"), "addPort:", eventTap, "forMode:$", @"kCFRunLoopDefaultMode")
  EndIf

  Repeat : Until WaitWindowEvent() = #PB_Event_CloseWindow
EndIf

[mk-soft]

Thanks for Hotkey example

here the complete HotKeyModifiers

Code: Select all

#cmdKeyBit = 8
#shiftKeyBit = 9
#alphaLockBit = 10
#optionKeyBit = 11
#controlKeyBit = 12
#rightShiftKeyBit = 13
#rightOptionKeyBit = 14
#rightControlKeyBit = 15
#cmdKey = 1 << #cmdKeyBit
#shiftKey = 1 << #shiftKeyBit
#alphaLock = 1 << #alphaLockBit
#optionKey = 1 << #optionKeyBit
#controlKey = 1 << #controlKeyBit
#rightShiftKey = 1 << #rightShiftKeyBit
#rightOptionKey = 1 << #rightOptionKeyBit
#rightControlKey = 1 << #rightControlKeyBit

GT

[deseven]

Thanks Shardik, wilbert and mk-soft! I wrote a module for that based on your code:
http://forums.purebasic.com/english/vie ... 14&t=64532

[NY152]

CocoaMessage() is not functon ... etc

EDIT:

CocoaMessage is a MACOX function sorry ...

Windows equivalent exists ?

[deseven]

well, yes