Using multiple monitors to display different windows

[Tasp]

I have 3 monitors, am I am trying to open a different window on each monitor. 
I have done this before but I'm unable to find the code to do this.
I was hoping the simple solution was just going to be moving the UpperLeftX 0-1920 for mon 1, 1921-3840 for mon 2 and 3841-5760 for mon 3. But it's not that simple....
There's also the question, as like me, for some reason I have my monitors setup as 2 - 1 - 3 so those positions would potentially be different. But if the user places the window at a position I can save that position and reopen it next time in the same one.
I have tried this, just collecting the screen position. But it shows at between 1 and 1920, doesn't show on which monitor.

Is there a way to identify which monitor the window is currently sat upon?

I think Janet helped with this last time, but this was on the old forum.

On a side note, has anyone seen Janet or John recently? I don't see those guys here anymore?

TIA 

[Chris Iverson]

For collecting the screen position, I suspect you're using GetWindowRect(), which is explicitly documented as returning screen co-ordinates. That is, they return the position relative to the top-left of the current screen.

I don't know if there's an actual one-step way to convert this to virtual-screen co-ordinates. You can use the MonitorFromWindow API to get a handle to the current monitor, and then GetMonitorInfo to get the workspace or full screen coordinates of the monitor, and do the math to get the co-ordinates.


If all you want is to save the current positioning of the window to restore it later, though, you may be better off using GetWindowPlacement and SetWindowPlacement.

Use GetWindowPlacement, and save all the info it gives you. You can then use SetWindowPlacement to restore it all at once.


Here's a sample I made for myself a while ago that combines all of these, when I was playing with going full-screen no matter what monitor I was on. Click "Fullscreen", and it should go full screen on whatever monitor it's currently on. Click "Windowed" to change it back, and try moving it to a different monitor.

   gosub [structdef]




   WindowWidth = 300
   WindowHeight = 300
   UpperLeftX = 300
   UpperLeftY = 300

   'Set defaults for Window Rect
   WINDOWRECT.left.struct = UpperLeftX
   WINDOWRECT.top.struct = UpperLeftY
   WINDOWRECT.right.struct = UpperLeftX + WindowWidth
   WINDOWRECT.bottom.struct = UpperLeftY + WindowHeight
   stylebits #m.g, 0, _WS_BORDER, 0, 0
   graphicbox #m.g, 0, 0, 300, 300
   button #m.b, "Fullscreen", [fsclick], UL, 100, 100, 100, 25
   stylebits #m, 0, 0, _WS_EX_TOPMOST, 0
   open "Hello" for window as #m
   #m, "trapclose [quit]"
   #m, "resizehandler [resize]"

   #m.g, "color black"
   #m.g, "down;fill black"

   hWnd = hwnd(#m)
   hButton  = hwnd(#m.b)

   wait

[quit]
   close #m
   end

[resize]
   #m.g, "locate 0 0 ";WindowWidth;" ";WindowHeight
   #m, "refresh"
   #m.g, "down;fill black"
   wait

[fsclick]
   winStyle = GetWindowLong(hWnd, _GWL_STYLE)

   'WS_OVERLAPPEDWINDOW corresponds to a combination of OVERLAPPED, SYSMENU,
   'THICKFRAME, CAPTION, MINIMIZEBOX, MAXIMIZEBOX.
   'Turning it off will produce a window with no system menu/buttons and no border.
   '
   'This is important for one reason: if the window manager detects such a window that is
   'filling up the monitor it is on, it will automatically hide the taskbar on that monitor.
   If winStyle AND _WS_OVERLAPPEDWINDOW Then
       'Get the position of the monitor we're on
       'Default to the primary monitor if it can't be determined
       hMonitor = MonitorFromWindow(hWnd, MONITOR.DEFAULTTOPRIMARY)

       'If we can't get the monitor info or the window's current position, we don't do anything
       If (GetMonitorInfo(hMonitor) AND GetWindowPlacement(hWnd)) then

           winStyle = winStyle XOR _WS_OVERLAPPEDWINDOW

           'NOOWNERZORDER prevents the window from changing position in the z-order,
           'FRAMECHANGED notifies the window manager that there's been a change and to recheck
           uFlags = _SWP_NOOWNERZORDER or _SWP_FRAMECHANGED

           a = SetWindowLong(hWnd, _GWL_STYLE, winStyle)
           a = SetWindowPos(hWnd, _HWND_TOP, MONITORINFO.rcMonitorLeft.struct, MONITORINFO.rcMonitorTop.struct,_
               (MONITORINFO.rcMonitorRight.struct - MONITORINFO.rcMonitorLeft.struct),_
               (MONITORINFO.rcMonitorBottom.struct - MONITORINFO.rcMonitorTop.struct), uFlags)

           'a = SetWindowText(hButton, "Windowed")
           #m.b "Windowed"
       End If
   Else
       winStyle = winStyle OR _WS_OVERLAPPEDWINDOW

       'NOZORDER tells SetWindowPos to ignore the hWndInsertAfter parameter
       'NOSIZE and NOMOVE tell SetWindowPos to ignore the size and position parameters.
       'The SetWindowPos call is only used to tell Windows that the Window styles have changed, and force it
       'to update.
       uFlags = _SWP_NOOWNERZORDER or _SWP_FRAMECHANGED or _SWP_NOZORDER or _SWP_NOSIZE or _SWP_NOMOVE

       a = SetWindowLong(hWnd, _GWL_STYLE, winStyle)
       a = SetWindowPlacement(hWnd)
       a = SetWindowPos(hWnd, _NULL, 0, 0, 0, 0, uFlags)

       'a = SetWindowText(hButton, "Fullscreen")
       #m.b "Fullscreen"
   End If
   wait

Function GetLastError()
   CallDLL #kernel32, "GetLastError",_
       GetLastError as long
End Function

Function GetWindowLong(hWnd, nIndex)
   CallDLL #user32, "GetWindowLongA",_
       hWnd as ulong,_
       nIndex as long,_
       GetWindowLong as long
End Function

Function SetWindowLong(hWnd, nIndex, newLong)
   CallDLL #user32, "SetWindowLongA",_
       hWnd as ulong,_
       nIndex as long,_
       newLong as long,_
       SetWindowLong as long
End Function

Function SetWindowPos(hWnd, hWInsertAfter, X, Y, cx, cy, uFlags)
   CallDLL #user32, "SetWindowPos",_
       hWnd as ulong,_
       hWInsertAfter as ulong,_
       X as long,_
       Y as long,_
       cx as long,_
       cy as long,_
       uFlags as long,_
       SetWindowPos as long
End Function

Function SetWindowText(hWnd, text$)
   CallDLL #user32, "SetWindowTextA",_
       hWnd as ulong,_
       text$ as ptr,_
       SetWindowText as long
End Function

Function MonitorFromWindow(hWnd, dwFlags)
   CallDLL #user32, "MonitorFromWindow",_
       hWnd as ulong,_
       dwFlags as long,_
       MonitorFromWindow as ulong
End Function

Function GetMonitorInfo(hMonitor)
   CallDLL #user32, "GetMonitorInfoA",_
       hMonitor as ulong,_
       MONITORINFO as struct,_
       GetMonitorInfo as long
End Function

Function GetWindowPlacement(hWnd)
   CallDLL #user32, "GetWindowPlacement",_
       hWnd as ulong,_
       WINDOWPLACEMENT as struct,_
       GetWindowPlacement as long
End Function

Function GetWindowRect(hWnd)
   CallDLL #user32, "GetWindowRect",_
       hWnd as ulong,_
       WINDOWRECT as struct,_
       GetWindowRect as long
End Function

Function SetWindowPlacement(hWnd)
   CallDLL #user32, "SetWindowPlacement",_
       hWnd as ulong,_
       WINDOWPLACEMENT as struct,_
       SetWindowPlacement as long
End Function

[structdef]

   struct MONITORINFO,_
       cbSize as long,_
       rcMonitorLeft as long,_
       rcMonitorTop as long,_
       rcMonitorRight as long,_
       rcMonitorBottom as long,_
       rcWorkLeft as long,_
       rcWorkTop as long,_
       rcWorkRight as long,_
       rcWorkBottom as long,_
       dwFlags as long

   MONITORINFO.cbSize.struct = len(MONITORINFO.struct)

   struct WINDOWPLACEMENT,_
       length as ulong,_
       flags as long,_
       showCmd as long,_
       ptMinPositionX as long,_
       ptMinPositionY as long,_
       ptMaxPositionX as long,_
       ptMaxPositionY as long,_
       rcNormalPositionLeft as long,_
       rcNormalPositionTop as long,_
       rcNormalPositionRight as long,_
       rcNormalPositionBottom as long


   WINDOWPLACEMENT.length.struct = len(WINDOWPLACEMENT.struct)

   struct WINDOWRECT,_
       left as long,_
       top as long,_
       right as long,_
       bottom as long

   global MONITOR.DEFAULTTONEAREST, MONITOR.DEFAULTTONULL, MONITOR.DEFAULTTOPRIMARY

   MONITOR.DEFAULTTONULL    = 0
   MONITOR.DEFAULTTOPRIMARY = 1
   MONITOR.DEFAULTTONEAREST = 2

   return

[Carl Gundel]

Sept 1, 2020 12:06:45 GMT -5 Chris Iverson said:

For collecting the screen position, I suspect you're using GetWindowRect(), which is explicitly documented as returning screen co-ordinates. That is, they return the position relative to the top-left of the current screen.

For LB5 I will try to support multiple displays. I believe that VisualWorks Smalltalk has support for this in the virtual machine in a way that I can capitalize on.

[Tasp]

Chris, Thanks for this, it's not exactly what I was looking for but actually does exactly what I need (I was looking at this wrongly).

It's took me a while to get my head around the basics, and I've actually learnt more about interacting with structs and API calls along the way. Whether I will remember any info is another matter.

Here's the snippet I needed, maybe this cut down version will help someone else.


gosub [structdef]

UpperLeftX = 500 : UpperLeftY = 500
button #m.1, "position",[getpos],    UL, 100,100
button #m.2, "move",    [move],      UL, 100, 150
button #m.3, "text",    [changetext],UL, 100, 200

OPEN "window" FOR window AS #m
#m, "trapclose [quit]"
hWnd = hwnd(#m)
WAIT

[changetext] 'Change window title
a = SetWindowText(hWnd, "text")
WAIT

[getpos] 'Get cureent window position on any monitor
a = GetWindowPlacement(hWnd)
print "Window Position"
print "ULX "; WINDOWPLACEMENT.rcNormalPositionLeft.struct
print "ULY "; WINDOWPLACEMENT.rcNormalPositionTop.struct

WAIT

[move] 'Move window
'Must fill struct first as I think it will contains window type info etc.
a = GetWindowPlacement(hWnd)
'UpperLeftX
WINDOWPLACEMENT.rcNormalPositionLeft.struct = -200
'UpperLeftY
WINDOWPLACEMENT.rcNormalPositionTop.struct = 200
'Bottom Right corner position
WINDOWPLACEMENT.rcNormalPositionRight.struct = 1000
'Bottom position
WINDOWPLACEMENT.rcNormalPositionBottom.struct = 1000

a = SetWindowPlacement(hWnd)


WAIT

[quit]
CLOSE #m
END

Function GetWindowPlacement(hWnd)
   CallDLL #user32, "GetWindowPlacement", hWnd as ulong, WINDOWPLACEMENT as struct, GetWindowPlacement as long
End Function

Function SetWindowPlacement(hWnd)
   CallDLL #user32, "SetWindowPlacement", hWnd as ulong, WINDOWPLACEMENT as struct, SetWindowPlacement as long
End Function

Function SetWindowText(hWnd, text$)
   CallDLL #user32, "SetWindowTextA", hWnd as ulong, text$ as ptr, SetWindowText as long
End Function


[structdef]
   struct WINDOWPLACEMENT, length as ulong, flags as long, showCmd as long, ptMinPositionX as long, ptMinPositionY as long, ptMaxPositionX as long, ptMaxPositionY as long, rcNormalPositionLeft as long, rcNormalPositionTop as long, rcNormalPositionRight as long, rcNormalPositionBottom as long
   WINDOWPLACEMENT.length.struct = len(WINDOWPLACEMENT.struct)

   global MONITOR.DEFAULTTONEAREST, MONITOR.DEFAULTTONULL, MONITOR.DEFAULTTOPRIMARY

return