ChangeRes

By | 2002-06-01

This Function will change your Windows Resolution. It is very simple, and it does what most Resolution Change Functions don’t do, it changes the the Bits Per Pixels as well as the Screen Width and Height.

Original Author: ScAnFrEaK

Inputs

Dim RetValue As Integer
RetValue = ChangeRes(800, 600, 32)

Returns

1 = Resolution Successfully Changed
0 = Resolution Was Not Changed

API Declarations

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
Private Const CCDEVICENAME = 32
Private Const CCFORMNAME = 32
Private Const DM_BITSPERPEL = &H60000
Private Const DM_PELSWIDTH = &H80000
Private Const DM_PELSHEIGHT = &H100000
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

Code

Function ChangeRes(Width As Single, Height As Single, BPP As Integer) As Integer
On Error GoTo ERROR_HANDLER
Dim DevM As DEVMODE, I As Integer, ReturnVal As Boolean, _
  RetValue, OldWidth As Single, OldHeight As Single, _
  OldBPP As Integer
  
  Call EnumDisplaySettings(0&, -1, DevM)
  OldWidth = DevM.dmPelsWidth
  OldHeight = DevM.dmPelsHeight
  OldBPP = DevM.dmBitsPerPel
  
  I = 0
  Do
    ReturnVal = EnumDisplaySettings(0&, I, DevM)
    I = I + 1
  Loop Until (ReturnVal = False)
  
  DevM.dmFields = DM_PELSWIDTH Or DM_PELSHEIGHT Or DM_BITSPERPEL
  DevM.dmPelsWidth = Width
  DevM.dmPelsHeight = Height
  DevM.dmBitsPerPel = BPP
  Call ChangeDisplaySettings(DevM, 1)
  RetValue = MsgBox("Do You Wish To Keep Your Screen Resolution To " & Width & "x" & Height & " - " & BPP & " BPP?", vbQuestion + vbOKCancel, "Change Resolution Confirm:")
  If RetValue = vbCancel Then
    DevM.dmPelsWidth = OldWidth
    DevM.dmPelsHeight = OldHeight
    DevM.dmBitsPerPel = OldBPP
    Call ChangeDisplaySettings(DevM, 1)
    MsgBox "Old Resolution(" & OldWidth & " x " & OldHeight & ", " & OldBPP & " Bit) Successfully Restored!", vbInformation + vbOKOnly, "Resolution Confirm:"
    ChangeRes = 0
  Else
    ChangeRes = 1
  End If
  Exit Function
ERROR_HANDLER:
  ChangeRes = 0
End Function

Author: dwirch

Derek Wirch is a seasoned IT professional with an impressive career dating back to 1986. He brings a wealth of knowledge and hands-on experience that is invaluable to those embarking on their journey in the tech industry.

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