Simple Console app to Get System DPI for future dpiAware apps on Windows 6 (Vista) onwards, the plan is to next build a template win32 GUI app and to test the UI scaling on my 2k monitor...

win32-GetSystemDPI-Console.asm

; #########################################################################
; 
; Program: win32-GetSystemDPI-Console
; Purpose: Simple Console app to Get System DPI for future dpiAware apps on Windows 6 (Vista) onwards 
; Author: Mark Albanese 
; Date: 28 February 2021
; Version: 1.0
; Release: 1
; Language: x86 Assembly / Microsoft Macro Assembler 
; Compiler: MASM32 SDK
; API reference: https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-getdevicecaps
; https://docs.microsoft.com/en-us/windows/win32/hidpi/high-dpi-desktop-application-development-on-windows
; Compatibility: Tested on Windows 95 after installing Vcredist.exe version 6.0 from some random website (in a VM). 
; Comments: Running on older systems shouldn't really be an issue with how I plan to implement this function i.e VerInfo.dwMajorVersion >= 6 etc.
;
; Note: This was a port of some C code found here:
; https://forums.codeguru.com/showthread.php?521245-GetDeviceCaps-issue-in-Windows-7-wrong-size
; 
; Next, I'll build a template win32 GUI app and test how it scales on my 2k monitor. 
; #########################################################################
    .386
    .model flat, stdcall
    option casemap :none   ; case sensitive
; #########################################################################
     include masm32rt.inc
; #########################################################################
   .data 
    Format   db "%.6G",0
    horzBuffer   db 32 dup(0)
    vertBuffer   db 32 dup(0)
    inchASmm qword 25.4f
    
    .data?
    hDC    HDC    ?
    cyLogPX qword ?
    cxLogPX qword ?
    horz qword ?
    vert qword ?
    horz2f qword ?
    vert2f qword ?

    .code
start:
; #########################################################################


    Call ScreenSizeInInches
    Call ScreenSizeInPixels
    Call ScreenSizeInLogicalPixels
    inkey
    exit

ScreenSizeInInches proc
    invoke GetDC,hDC
        push eax
        invoke GetDeviceCaps,eax,HORZSIZE
        push    offset horz
        push    eax
        call    dwtoa 
        pop eax

        push eax
        invoke GetDeviceCaps,eax,VERTSIZE
        push    offset vert
        push    eax
        call    dwtoa 
        pop eax
    invoke ReleaseDC,hDC,eax 
    
    invoke StrToFloat, ADDR horz, ADDR horz2f
    invoke StrToFloat, ADDR vert, ADDR vert2f
    
    finit
    fld    qword ptr [horz2f]
    fld    qword ptr [inchASmm]
    fdiv 
    fstp   qword ptr [horz2f]
    
    invoke crt_sprintf,ADDR horzBuffer,ADDR Format,horz2f
    
    finit
    fld    qword ptr [vert2f]
    fld    qword ptr [inchASmm]
    fdiv 
    fstp   qword ptr [vert2f]
    
    invoke crt_sprintf,ADDR vertBuffer,ADDR Format,vert2f
    
    print "Your screen size in inches is "
    print Addr horzBuffer,34
    print " x "
    print Addr vertBuffer,34,13,10
    
    ret
ScreenSizeInInches endp

ScreenSizeInPixels proc
    invoke GetDC,hDC
        push eax
        invoke GetDeviceCaps,eax,HORZRES
        push    offset horz
        push    eax
        call    dwtoa 
        pop eax
        
        push eax
        invoke GetDeviceCaps,eax,VERTRES
        push    offset vert
        push    eax
        call    dwtoa 
        pop eax
    invoke ReleaseDC,hDC,eax 
    
    print "Your screen size in pixels is "
    print ADDR horz
    print " x "
    print ADDR vert,13,10

    ret
ScreenSizeInPixels endp

ScreenSizeInLogicalPixels proc
    invoke GetDC,hDC
        push eax
        invoke GetDeviceCaps,eax,LOGPIXELSX
        push    offset cxLogPX
        push    eax
        call    dwtoa 
        pop eax
        
        push eax
        invoke GetDeviceCaps,eax,LOGPIXELSY
        push    offset cyLogPX
        push    eax
        call    dwtoa 
        pop eax
    invoke ReleaseDC,hDC,eax 
    
    print "Your screen size in logical pixels is "
    print Addr cxLogPX
    print " x "
    print Addr cyLogPX,13,10
    ret
ScreenSizeInLogicalPixels endp

end start
; #########################################################################
; Note: my screen res scale was set at 125% when I ran this test:

; Your screen size in inches is 23.937" x 13.9764"
; Your screen size in pixels is 2048 x 1152
; Your screen size in logical pixels is 96 x 96
; Press any key to continue ...

;Here it is at 100%...

;Your screen size in inches is 23.937" x 13.9764"
;Your screen size in pixels is 2560 x 1440
;Your screen size in logical pixels is 96 x 96
;Press any key to continue ...