Attribute VB_Name = "modScreenRes"
Option Explicit

Private Const BITSPIXEL = 12&
Private Const CCDEVICENAME = 32
Private Const CCFORMNAME = 32
Private Const DM_BITSPERPEL = &H40000
Private Const DM_PELSWIDTH = &H80000
Private Const DM_PELSHEIGHT = &H100000
Private Const CDS_TEMP = &H4

Private Type DEVMODE
    dmDeviceName As String * CCDEVICENAME
    dmSpecVersion As Integer
    dmDriverVersion As Integer
    dmSize As Integer
    dmDriverExtra As Integer
    dmFields As Long
    dmOrientation As Integer
    dmPaperSize As Integer
    dmPaperLength As Integer
    dmPaperWidth As Integer
    dmScale As Integer
    dmCopies As Integer
    dmDefaultSource As Integer
    dmPrintQuality As Integer
    dmColor As Integer
    dmDuplex As Integer
    dmYResolution As Integer
    dmTTOption As Integer
    dmCollate As Integer
    dmFormName As String * CCFORMNAME
    dmUnusedPadding As Integer
    dmBitsPerPel As Integer
    dmPelsWidth As Long
    dmPelsHeight As Long
    dmDisplayFlags As Long
    dmDisplayFrequency As Long
End Type

Private Type RECT
    Left As Long
    Top As Long
    Right As Long
    Bottom As Long
End Type


Private Declare Function GetDesktopWindow Lib "User32" () As Long
Private Declare Function GetWindowRect Lib "User32" (ByVal hWnd As Long, lpRect As RECT) As Long
Private Declare Function GetDC Lib "User32" (ByVal hWnd As Long) As Long
Private Declare Function GetDeviceCaps Lib "gdi32" (ByVal hdc As Long, ByVal nIndex As Long) As Long
Private Declare Function EnumDisplaySettings Lib "User32" Alias "EnumDisplaySettingsA" (ByVal lpszDeviceName As Long, ByVal iModeNum As Long, lpDevMode As Any) As Boolean
Private Declare Function ChangeDisplaySettings Lib "User32" Alias "ChangeDisplaySettingsA" (lpDevMode As Any, ByVal dwFlags As Long) As Long


Public Sub GetScreenRes(WidthPixels As Long, HeightPixels As Long, BitDepth As Long)
    Dim vR As RECT
    Call GetWindowRect(GetDesktopWindow, vR)
    WidthPixels = vR.Right
    HeightPixels = vR.Bottom
    BitDepth = GetDeviceCaps(GetDC(GetDesktopWindow), BITSPIXEL)
End Sub

Public Function SetScreenRes(ByVal WidthPixels As Long, ByVal HeightPixels As Long, ByVal BitDepth As Long) As Boolean
    Dim DevM As DEVMODE
    Call EnumDisplaySettings(0&, 0&, DevM)
    DevM.dmFields = DM_PELSWIDTH Or DM_PELSHEIGHT Or DM_BITSPERPEL
    DevM.dmPelsWidth = WidthPixels
    DevM.dmPelsHeight = HeightPixels
    DevM.dmBitsPerPel = BitDepth
    SetScreenRes = (ChangeDisplaySettings(DevM, CDS_TEMP) = 0)
End Function