Generate keyboard events for the frontmost application

Question

In Mac OS / Cocoa, may I synthesize keyboard entries - strings - for the frontmost application in a transparent way?

To be more precise, I don't want to send special characters or control sequences. My only need is to send standard characters.

Just learned here, that AppleScript can do the trick like this:

tell application "TextEdit"
    activate

    tell application "System Events"
        keystroke "f" using {command down}
    end tell
end tell

Q: How would I do this using ObjC / cocoa?

UPDATE 2012-02-18 - Nicks proposal enhanced

Based on Nick's code below, here is the final solution:

// First, get the PSN of the currently front app
ProcessSerialNumber psn;
GetFrontProcess( &psn );

// make some key events
CGEventRef keyup, keydown;
keydown = CGEventCreateKeyboardEvent (NULL, (CGKeyCode)6, true);
keyup = CGEventCreateKeyboardEvent (NULL, (CGKeyCode)6, false);

// forward them to the frontmost app
CGEventPostToPSN (&psn, keydown); 
CGEventPostToPSN (&psn, keyup); 

// and finally behave friendly
CFRelease(keydown);
CFRelease(keyup);

Using this method, a click on a button of a non-activating panel targets the event to the actual front application. Perfectly what I want to do.

Solution

Sure, you'll want to use CGEventCreateKeyboardEvent to create keyboard events, then post them as such:

    CGEventRef keyup, keydown;
    keydown = CGEventCreateKeyboardEvent (NULL, (CGKeyCode)56, true);
    keyup = CGEventCreateKeyboardEvent (NULL, (CGKeyCode)56, false);

    CGEventPost(kCGHIDEventTap, keydown);
    CGEventPost(kCGHIDEventTap, keyup);
    CFRelease(keydown);
    CFRelease(keyup);

It's a bit more complicated than AppleScript but it does the trick. You do have to explicitly post a keydown and then a keyup event. More information at the Quartz Event Services Reference.

Comments

[SteAp]

Thank you! Never did anything at such a low level.