Setting Cursor from Background (Re: Hotkey/Cursor/Windowing questions)

FROM : daniel
DATE : Tue Oct 12 18:02:30 2004

I ran into this a year or two ago.  I ended up solving this by looking 
carefully at what programs like the "screen capture" do.  I ended up 
with this (TOTALLY UNSUPPORTED) wokraround, which uses TOTALLY 
UNSUPPORTED, undocumented calls.  If getting the behavior is more 
important than following the rules, this might be useful.

The fact that there is a property named "SetsCursorInBackground" is at 
least indicative that there is no easy workaround to the problem.

#if EXPLOITBACKGROUNDCURSORHACK    
            long sysVers = GetSystemVersion();

            // This trick doesn't work on 10.1
            if (sysVers >= 0x1020)
            {
       void CGSSetConnectionProperty(int, int, int, int);
       int CGSCreateCString(char *);
       int CGSCreateBoolean(BOOL);
       int    _CGSDefaultConnection();
       void CGSReleaseObj(int);
       int propertyString, boolVal;
       
       // Hack to make background cursor setting work
       propertyString = CGSCreateCString("SetsCursorInBackground");
       boolVal = CGSCreateBoolean(TRUE);
       CGSSetConnectionProperty(_CGSDefaultConnection(), 
_CGSDefaultConnection(), propertyString, boolVal);
       CGSReleaseObj(propertyString);
       CGSReleaseObj(boolVal);
            }
#endif

On Oct 12, 2004, at 12:51 AM, Sloan Kahsen wrote:

> Hello everyone,
>
> Thanks to some code I've been cobbling together from here and various 
> online sources, I've been able to get somewhat close to what I'm 
> trying to do... My goal is to have a hotkey be hit, then the cursor 
> change, an invisible (transparent) window appear above all others, and 
> then I'm going to do an action on that window. Here is my hotkey code:
>
> - (IBAction)hitHotKey: (id)sender
> {
>     [NSApp activateIgnoringOtherApps: YES];            
>
>     if (fingerCursor == nil)
>     {
>         fingerCursor = [[NSCursor alloc] initWithImage: [NSImage imageNamed: 
> @"myPic"]
>         hotSpot: NSMakePoint (0, 0)];
>         [fingerCursor set];
>     }
>     else
>         [fingerCursor set];
> }
>
> Problem 1) If I *don't* have the activateIgnoringOtherApps, I can't 
> get the custom cursor to appear, however when I do have it, it brings 
> my app frontmost, but I don't get the cursor (though I see it for a 
> second). The cursor remains an arrow until I activate the key sequence 
> again.
>
> Problem 2) Actually I want to *not* have my app come frontmost when I 
> activate this hotkey. I suppose if my cursor could simply change and 
> then if I could put a transparent window above all others, I would be 
> set (similar to the functionality of Quicksilver for example - hit a 
> hotkey, window comes up but you are still in your frontmost app even 
> though QS is taking your keystrokes). My hang up is the cursor change 
> while the app is in the background. The Finder can do it if you 
> perform the key sequence command-shift-4-space for example (camera) 
> even while in the background (or is it a function of the dock?) Any 
> tips or insight on this would be greatly appreciated!
>
> Thanks.
>
> Sloan
>
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