Win32: EVENT_APPRESUME, EVENT_APPSUSPEND (and so AppSuspended) broken

[GWRon]

The current revisions of brl.system contain a non working AppResume/Suspend handling (recognition of application is send into the background / alt-tabbed)

Sample:

SuperStrict
Framework Brl.D3D9Max2D

Graphics 800, 600 ', 32
SetBlend AlphaBlend

Function GraphicsHook:Object( id:Int,data:Object,context:Object )
    Local ev:TEvent=TEvent(data)
    If Not ev Return data
    
    Select ev.id
        Case EVENT_APPRESUME
            Print "GAINED"
        Case EVENT_APPSUSPEND
            Print "LOST"
    End Select

    Return data
End Function

AddHook EmitEventHook,GraphicsHook,Null,0


Repeat
    Cls
    
    Global informed:Int = False
    If AppSuspended() 
        If Not informed
            Print "suspended"
            informed = True
        EndIf
    Else
        informed = False
    EndIf
    Flip
Until AppTerminate() Or KeyHit(KEY_ESCAPE)

system.win32.c contains this:

	case WM_ACTIVATE:
		if( LOWORD(wp)==WA_INACTIVE || !IsIconic(hwnd) ){
			DWORD proc;
			GetWindowThreadProcessId( hwnd,&proc );
			if( proc!=GetCurrentProcessId() ){
				id = (LOWORD(wp) == WA_INACTIVE) ? BBEVENT_APPSUSPEND : BBEVENT_APPRESUME;
				break;
			}
		}
		return;

-> so either "if suspended or not minimized"
-> and the event must be initiated by some other process

The second condition is not met (other process should initiate it).

To fix it we could simply change:

			if( proc!=GetCurrentProcessId() ){
//to
			if( proc==GetCurrentProcessId() ){

if we want to only resume and suspend if the application should be the reason for the change.
But this would break if your application had multiple windows - because now it suspends/resums if you switch "inner" windows.

I guess this more likely has to be removed at all - and we suspend/resume simply by being loosing focus or gaining focus (ignoring multi-window) OR ... identify if GetCurrentProcessId() does incorrectly return the calling process or so.

then there is the already commented out code:

	case WM_ACTIVATEAPP:
		//
		// WM_ACTIVATEAPP appears to be broken.
		//
		// Clicking on taskbar button to minimize an app appears to confuse poor old windows.
		//
		// So, we'll use the WM_ACTIVATE code above courtesy of Seb...
		//
		id=wp ? BBEVENT_APPRESUME : BBEVENT_APPSUSPEND;
		break;
		*/

which is the one we should use when we only want to resume/suspend when not switching "inner" Windows (so "Alt-Tab" in a single window application). It would not suspend/resume if inner windows focus changes between each other.

[GWRon]

	case WM_ACTIVATE:
		if( LOWORD(wp)==WA_INACTIVE || !IsIconic(hwnd) ){
			DWORD proc;
			GetWindowThreadProcessId( hwnd,&proc );
			if( proc!=GetCurrentProcessId() ){
				id = (LOWORD(wp) == WA_INACTIVE) ? BBEVENT_APPSUSPEND : BBEVENT_APPRESUME;
				break;
			}
		}
		return;

GetWindowThreadProcessId(hwnd, &proc) : returns the process ID associated with hwnd
GetCurrentProcessId(): returns the current process ID of the calling process

As hwnd is our own's application window doesn't that mean that proc is always the same as GetCurrentProcessId() ?

A potential alternative would be:

	case WM_ACTIVATE:
		if (LOWORD(wp) == WA_INACTIVE) {
			HWND fgWindow = GetForegroundWindow();
			if (fgWindow && fgWindow != hwnd) {
				id = BBEVENT_APPSUSPEND;
				break;
			}
		} else {
			id = BBEVENT_APPRESUME;
			break;
		}

so it should only suspend if a different window was the reason.

Normal alt-tab works there... but when doing minimize (send to taskbar) and then restore the window ... it somehow sends out APPRESUME 2 times (WM_ACTIVATE is send two times).

If we brought back the !IsIconic() right on top ... then it only resumes if we restore from the task bar, but not from alt-tab.

So I made up this version - which seems to work with Alt-Tab and also minimize-restore:

	case WM_ACTIVATE:
		if( LOWORD(wp)==WA_INACTIVE){
			HWND fgWindow = GetForegroundWindow();
			if (fgWindow && fgWindow != hwnd) {
				id = BBEVENT_APPSUSPEND;
				break;
			}
		} else {
			//skip sending out a second RESUME in case 
			//having been minimized before
			if(IsIconic(hwnd)) {
				return;
			}
			id = BBEVENT_APPRESUME;
			break;
		}

But this still does not "trigger" if you minimize/maximize by clicking on the taskbar entry, not the "minimize button of the window"

[GWRon]

Seems we could use the HIWORD to understand "where" things reside afterwards (the HIWORD value meaning is undocumented...)

Action	Log	wParam	lParam
Application start	WM_ACTIVATE (RESUME)	1	0
Other application window (eg MaxIDE): clicked	WM_ACTIVATE (SUSPEND)	0	0
Taskbar entry click while in background	WM_ACTIVATE (RESUME)	1	0
Other application window (eg MaxIDE): clicked	WM_ACTIVATE (SUSPEND)	0	0
Application window clicked	WM_ACTIVATE (RESUME)	2	0
Taskbar entry clicked to minimize EVENT 1/2	WM_ACTIVATE (SUSPEND)	0	0
Taskbar entry clicked to minimize EVENT 2/2	WM_ACTIVATE (RESUME)	1	32
Taskbar entry clicked to open again	WM_ACTIVATE (RESUME)	1	0
Application window minimize button clicked	WM_ACTIVATE (SUSPEND)	0	32
Taskbar entry clicked to open again EVENT 1/2	WM_ACTIVATE (RESUME)	1	32
Taskbar entry clicked to open again EVENT 2/2	WM_ACTIVATE (RESUME)	1	0

wParam = 2 if mouse was used, 1 for keyboard or system way to activate (according to docs)
0 is of course ... the deactivation/suspend.

For me that looks like we should ignore events if we are "resuming" and lParam (HIWORD(wp)) is 32 (taskbar stuff).
Yet there is one exception: when clicking on the taskbar to minimize WHILE the application had already focus/was in foreground, leads to two events - one suspend and another resume (as the application has still "focus" while being in the taskbar ... so I guess it is fair to still see it as "resumed" / "not suspended"). On the other hand - if we ignored all "32" ones, then it would only give 1 signal per "resume" and 1 per "suspend".

Edit:

	case WM_ACTIVATE:
		if( LOWORD(wp)==WA_INACTIVE){
		printf("WM_ACTIVATE (SUSPEND): wParam=%d, lParam=%d\n", LOWORD(wp), HIWORD(wp));
		fflush(stdout);
			id = BBEVENT_APPSUSPEND;
			break;
		} else {
		printf("WM_ACTIVATE (RESUME): wParam=%d, lParam=%d\n", LOWORD(wp), HIWORD(wp));
		fflush(stdout);
			id = BBEVENT_APPRESUME;
			break;
		}

This is what I used to log out things in the system.win32.c file