Understanding return values from DPI Awareness Context

[WildByDesign]

I'm playing around with the DPI related functions for DPI Awareness Context from UEZ's _WinAPI_DPI.au3 UDF. I need to be able to get the DPI Awareness Context values and make decisions based on those returns.

The part that I don't understand is that the values for these are:

$DPI_AWARENESS_UNAWARE = 0
Global Const $DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE = $DPI_AWARENESS_UNAWARE - 3
Global Const $DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2 = $DPI_AWARENESS_UNAWARE - 4

So my assumption is that I would get a return of -3 for PMv1 and -4 for PMv2.

But instead, I am getting a return of 18 for PMv1 and 34 for PMv2. I assume that there must be a way to interpret this return to match the initial -3 or -3 that I thought were the values.

If anyone can help me understand this better, I would greatly appreciate it.

Here is the script that I am testing:

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#include <GUIConstantsEx.au3>

;https://learn.microsoft.com/en-us/windows/win32/api/windef/ne-windef-dpi_awareness
Global Enum $DPI_AWARENESS_INVALID = -1, $DPI_AWARENESS_UNAWARE = 0, $DPI_AWARENESS_SYSTEM_AWARE = 1, $DPI_AWARENESS_PER_MONITOR_AWARE = 2

;https://learn.microsoft.com/en-us/windows/win32/hidpi/dpi-awareness-context
Global Const $DPI_AWARENESS_CONTEXT_UNAWARE = $DPI_AWARENESS_UNAWARE - 1
Global Const $DPI_AWARENESS_CONTEXT_SYSTEM_AWARE = $DPI_AWARENESS_UNAWARE - 2
Global Const $DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE = $DPI_AWARENESS_UNAWARE - 3
Global Const $DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2 = $DPI_AWARENESS_UNAWARE - 4
Global Const $DPI_AWARENESS_CONTEXT_UNAWARE_GDISCALED = $DPI_AWARENESS_UNAWARE - 5

; Per-MonitorV2
;_WinAPI_SetProcessDpiAwarenessContext($DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2)

; Per-MonitorV1
_WinAPI_SetProcessDpiAwarenessContext($DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE)

Example()

Func Example()
    ; Create a GUI with various controls.
    Local $hGUI = GUICreate("Example", 400, 400)
    Local $idBtn_OK = GUICtrlCreateButton("OK", 310, 370, 85, 25)


    ; Display the GUI.
    GUISetState(@SW_SHOW, $hGUI)

    ConsoleWrite("AwarenessContext from _WinAPI_GetWindowDpiAwarenessContext($hWnd): " & _WinAPI_GetWindowDpiAwarenessContext($hGUI) & @CRLF)
    ConsoleWrite("AwarenessContext from _WinAPI_GetThreadDpiAwarenessContext(): " & _WinAPI_GetThreadDpiAwarenessContext() & @CRLF)

    ; Loop until the user exits.
    While 1
        Switch GUIGetMsg()
            Case $GUI_EVENT_CLOSE, $idBtn_OK
                ExitLoop

        EndSwitch
    WEnd

    ; Delete the previous GUI and all controls.
    GUIDelete($hGUI)
EndFunc   ;==>Example

; All DPI-related functions below are from UEZ's _WinAPI_DPI.au3 UDF.

;https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setprocessdpiawarenesscontext
Func _WinAPI_SetProcessDpiAwarenessContext($DPI_AWARENESS_CONTEXT_value)
    Local $aResult = DllCall("user32.dll", "bool", "SetProcessDpiAwarenessContext", @AutoItX64 ? "int64" : "int", $DPI_AWARENESS_CONTEXT_value) ;requires Win10 v1703+ / Windows Server 2016+
    If Not IsArray($aResult) Or @error Then Return SetError(1, @extended, 0)
    If Not $aResult[0] Then Return SetError(2, @extended, 0)
    Return $aResult[0]
EndFunc   ;==>_WinAPI_SetProcessDpiAwarenessContext

;https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getwindowdpiawarenesscontext
Func _WinAPI_GetWindowDpiAwarenessContext($hWnd)
    Local $aResult = DllCall("user32.dll", "uint", "GetWindowDpiAwarenessContext", "hwnd", $hWnd) ;requires Win10 v1607+ / no server support
    If Not IsArray($aResult) Or @error Then Return SetError(1, @extended, 0)
    If Not $aResult[0] Then Return SetError(2, @extended, 0)
    Return $aResult[0]
EndFunc   ;==>_WinAPI_GetWindowDpiAwarenessContext

;https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getthreaddpiawarenesscontext
Func _WinAPI_GetThreadDpiAwarenessContext()
    Local $aResult = DllCall("user32.dll", "uint", "GetThreadDpiAwarenessContext") ;requires Win10 v1607+ / no server support
    If Not IsArray($aResult) Or @error Then Return SetError(1, @extended, 0)
    If Not $aResult[0] Then Return SetError(2, @extended, 0)
    Return $aResult[0]
EndFunc   ;==>_WinAPI_GetThreadDpiAwarenessContext

 

Edited 1 hour ago by WildByDesign
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