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Active Forums => Programs => Topic started by: SpriggsySpriggs on June 02, 2021, 03:50:32 pm

Title: Change Resolution with WinAPI functions
Post by: SpriggsySpriggs on June 02, 2021, 03:50:32 pm
The below code can be used to change resolution for a given monitor in Windows. This was tested on Windows 10 20H2 64 bit using the 64 bit IDE. It does not work in 32 bit as of yet. It requires v1.5 or higher to compile as-is. The code asks for input for which monitor to change (starting with zero as the first), then the width and height to change to.

Code: QB64: [Select]
  2. $If VERSION < 1.5 Then
  3.     $ERROR Stable build v1.5 or higher is required
  5. $If 32BIT Then
  6.     $ERROR This code can only be ran in the 64 bit IDE at the moment
  8.  
  11.  
  12. Const CHANGE_MODE = 1
  13.  
  14. Const DISP_CHANGE_SUCCESSFUL = 0
  15.  
  16. Const CDS_FULLSCREEN = &H00000004
  17.  
  18. Type POINTL
  19.     As Long x, y
  21.  
  22. Type DEVMODE
  23.     As String * 32 dmDeviceName
  24.     As Integer dmSpecVersion, dmDriverVersion, dmSize, dmDriverExtra
  25.     As Long dmFields
  26.     As POINTL dmPosition
  27.     As Long dmDisplayOrientation, dmDisplayFixedOutput
  28.     As Integer dmColor, dmDuplex, dmYResolution, dmTTOption, dmCollate
  29.     As String * 32 dmFormName
  30.     As Integer dmLogPixels
  31.     As Long dmBitsPerPel, dmPelsWidth, dmPelsHeight, dmDisplayFlags, dmDisplayFrequency, dmICMMethod, dmICMIntent, dmMediaType, dmDitherType, dmReserved1, dmReserved2, dmPanningWidth, dmPanningHeight
  33.  
  34. Type DISPLAY_DEVICE
  35.     As Long cb
  36.     As String * 32 DeviceName
  37.     As String * 128 DeviceString
  38.     As Long StateFlags
  39.     As String * 128 DeviceID, DeviceKey
  41.  
  43.     Function EnumDisplayDevices%% Alias "EnumDisplayDevicesA" (ByVal lpDevice As _Offset, Byval iDevNum As Long, Byval lpDisplayDevice As _Offset, Byval dwFlags As Long)
  44.     Function EnumDisplaySettings%% Alias "EnumDisplaySettingsA" (ByVal lpszDeviceName As _Offset, Byval iModeNum As Long, Byval lpDevMode As _Offset)
  45.     Function ChangeDisplaySettings& Alias "ChangeDisplaySettingsExA" (ByVal lpszDeviceName As _Offset, Byval lpDevMode As _Offset, Byval hwnd As _Offset, Byval dwflags As Long, Byval lParam As _Offset)
  46.     Function GetLastError& ()
  48.  
  49. Dim As DISPLAY_DEVICE adapter: adapter.cb = Len(adapter)
  50. Dim As Long adapterIndex: adapterIndex = 0
  51. Dim As _Byte targetModeFound: targetModeFound = 0
  52. Dim As String * 32 targetDeviceName
  53. Dim As DEVMODE targetMode
  54.  
  55. Dim As Long index, dispwidth, dispheight
  56.  
  57. Input "Enter monitor index (zero based): ", index
  58. Input "Enter display width and height, separated by comma: ", dispwidth, dispheight
  59.  
  60. While EnumDisplayDevices(0, adapterIndex, _Offset(adapter), 0)
  61.     Dim As DEVMODE mode: mode.dmSize = Len(mode)
  62.     Dim As Long modeIndex: modeIndex = 0
  63.     While EnumDisplaySettings(_Offset(adapter.DeviceName), modeIndex, _Offset(mode))
  64.         If Not targetModeFound And adapterIndex = index Then
  65.             If CHANGE_MODE And mode.dmPelsWidth = dispwidth And mode.dmPelsHeight = dispheight And mode.dmDisplayFrequency >= 59 And mode.dmDisplayFrequency <= 60 Then
  66.                 targetModeFound = Not targetModeFound
  67.                 targetDeviceName = adapter.DeviceName
  68.                 targetMode = mode
  69.             End If
  70.         End If
  71.         modeIndex = modeIndex + 1
  72.     Wend
  73.     adapterIndex = adapterIndex + 1
  75. If targetModeFound Then
  76.     Dim As Long r
  77.     r = ChangeDisplaySettings(_Offset(targetDeviceName), _Offset(targetMode), 0, CDS_FULLSCREEN, 0)
  78.     _Assert r = DISP_CHANGE_SUCCESSFUL, Str$(r)
  79.  
  80.     Sleep
  81.  
  82.     r = ChangeDisplaySettings(_Offset(targetDeviceName), 0, 0, 0, 0)
  83.     _Assert r = DISP_CHANGE_SUCCESSFUL, Str$(r)
Title: Re: Change Resolution with WinAPI functions
Post by: OldsCool on June 02, 2021, 04:01:58 pm
Thought I'd give it a try. loaded it in QB v1.4. have an IDE error on line 32 - 'Expected variablename AS type or END TYPE...I'll upgrade to latest QB64 version. that may be it?

 update...I'm guessing it's the Win7 / 32bit machine I'm using right now...good luck didn't want to waste your time.
Title: Re: Change Resolution with WinAPI functions
Post by: SpriggsySpriggs on June 02, 2021, 04:34:06 pm
Quote from: OldsCool on June 02, 2021, 04:01:58 pm
Thought I'd give it a try. loaded it in QB v1.4. have an IDE error on line 32 - 'Expected variablename AS type or END TYPE...I'll upgrade to latest QB64 version. that may be it?

@OldsCool Oh, this code would require at least stable build v1.5 to compile due to the newer way of declaring variables. You can get the latest stable or the dev build for your Windows 7 machine still.
Title: Re: Change Resolution with WinAPI functions
Post by: OldsCool on June 02, 2021, 06:10:48 pm
Awesome, thanks. I can see many uses for this. I'll upgrade (thought so...) and try it.
Title: Re: Change Resolution with WinAPI functions
Post by: OldsCool on June 02, 2021, 06:18:27 pm
I just read the second line of your previous post, missed it somehow...Older QB64 versions have been running flawlessly on my Win7/32 machine. I was mostly wondering about the compatibility of your routine with Win7 itself, i Figured the error I was getting was a version issue. if you're still interested I'll let you know how it goes once I upgrade, thanks again .
Title: Re: Change Resolution with WinAPI functions
Post by: SpriggsySpriggs on June 02, 2021, 06:36:36 pm
@OldsCool I actually updated the post after you mentioned it. You didn't miss anything. Glad you are showing some interest in the thread, though
Title: Re: Change Resolution with WinAPI functions
Post by: SpriggsySpriggs on June 02, 2021, 08:02:01 pm
@OldsCool You can forget trying to run it as a 32 bit executable. The code doesn't currently work in 32 bit. I tried it myself on another computer. Oh well. 64 bit is the more common build of Windows anyways
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