I'm looking for a way to rotate the display of one of my monitors programmatically. I have two monitors set up on a desk mount, and I often use them in varying orientations when programming or using various other programs, and in order to change the orientation I jump into display settings and rotate it that way (so i can have one or both in portrait).
Call me lazy as i know thats hardly any hassle to do, but it would be nice to just have a quick little executable on my taskbar that i can run to instantly rotate one of the screens back and forth when i need to.
I've looked into it and found various explanations using DEVMODE structs etc, and it all seems like a really long winded process, is there really not an easier way to do this? Not a windows dll that has this functionailty already?
Thanks in advance.
it's not that hard to achieve this using the mentioned DEVMODE struct and native calls. I've written a little wrapper that does this:
using System;
using System.Runtime.InteropServices;
public class Display
{
public enum Orientations
{
DEGREES_CW_0 = 0,
DEGREES_CW_90 = 3,
DEGREES_CW_180 = 2,
DEGREES_CW_270 = 1
}
public static bool Rotate(uint DisplayNumber, Orientations Orientation)
{
if(DisplayNumber == 0)
throw new ArgumentOutOfRangeException("DisplayNumber", DisplayNumber, "First display is 1.");
bool result = false;
DISPLAY_DEVICE d = new DISPLAY_DEVICE();
d.cb = Marshal.SizeOf(d);
DEVMODE dm = new DEVMODE();
if(!NativeMethods.EnumDisplayDevices(null, DisplayNumber-1, ref d, 0))
throw new ArgumentOutOfRangeException("DisplayNumber", DisplayNumber, "Number is greater than connected displays.");
if (0 != NativeMethods.EnumDisplaySettings(
d.DeviceName, NativeMethods.ENUM_CURRENT_SETTINGS, ref dm))
{
if ((dm.dmDisplayOrientation + (int)Orientation) % 2 == 1) // Need to swap height and width?
{
int temp = dm.dmPelsHeight;
dm.dmPelsHeight = dm.dmPelsWidth;
dm.dmPelsWidth = temp;
}
switch (Orientation)
{
case Orientations.DEGREES_CW_90:
dm.dmDisplayOrientation = NativeMethods.DMDO_270;
break;
case Orientations.DEGREES_CW_180:
dm.dmDisplayOrientation = NativeMethods.DMDO_180;
break;
case Orientations.DEGREES_CW_270:
dm.dmDisplayOrientation = NativeMethods.DMDO_90;
break;
case Orientations.DEGREES_CW_0:
dm.dmDisplayOrientation = NativeMethods.DMDO_DEFAULT;
break;
default:
break;
}
DISP_CHANGE ret = NativeMethods.ChangeDisplaySettingsEx(
d.DeviceName, ref dm, IntPtr.Zero,
DisplaySettingsFlags.CDS_UPDATEREGISTRY, IntPtr.Zero);
result = ret == 0;
}
return result;
}
public static void ResetAllRotations()
{
try
{
uint i = 0;
while (++i <= 64)
{
Rotate(i, Orientations.DEGREES_CW_0);
}
}
catch(ArgumentOutOfRangeException ex)
{
// Everything is fine, just reached the last display
}
}
}
internal class NativeMethods
{
[DllImport("user32.dll")]
internal static extern DISP_CHANGE ChangeDisplaySettingsEx(
string lpszDeviceName, ref DEVMODE lpDevMode, IntPtr hwnd,
DisplaySettingsFlags dwflags, IntPtr lParam);
[DllImport("user32.dll")]
internal static extern bool EnumDisplayDevices(
string lpDevice, uint iDevNum, ref DISPLAY_DEVICE lpDisplayDevice,
uint dwFlags);
[DllImport("user32.dll", CharSet = CharSet.Ansi)]
internal static extern int EnumDisplaySettings(
string lpszDeviceName, int iModeNum, ref DEVMODE lpDevMode);
public const int DMDO_DEFAULT = 0;
public const int DMDO_90 = 1;
public const int DMDO_180 = 2;
public const int DMDO_270 = 3;
public const int ENUM_CURRENT_SETTINGS = -1;
}
// See: https://msdn.microsoft.com/en-us/library/windows/desktop/dd183565(v=vs.85).aspx
[StructLayout(LayoutKind.Explicit, CharSet = CharSet.Ansi)]
internal struct DEVMODE
{
public const int CCHDEVICENAME = 32;
public const int CCHFORMNAME = 32;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = CCHDEVICENAME)]
[System.Runtime.InteropServices.FieldOffset(0)]
public string dmDeviceName;
[System.Runtime.InteropServices.FieldOffset(32)]
public Int16 dmSpecVersion;
[System.Runtime.InteropServices.FieldOffset(34)]
public Int16 dmDriverVersion;
[System.Runtime.InteropServices.FieldOffset(36)]
public Int16 dmSize;
[System.Runtime.InteropServices.FieldOffset(38)]
public Int16 dmDriverExtra;
[System.Runtime.InteropServices.FieldOffset(40)]
public DM dmFields;
[System.Runtime.InteropServices.FieldOffset(44)]
Int16 dmOrientation;
[System.Runtime.InteropServices.FieldOffset(46)]
Int16 dmPaperSize;
[System.Runtime.InteropServices.FieldOffset(48)]
Int16 dmPaperLength;
[System.Runtime.InteropServices.FieldOffset(50)]
Int16 dmPaperWidth;
[System.Runtime.InteropServices.FieldOffset(52)]
Int16 dmScale;
[System.Runtime.InteropServices.FieldOffset(54)]
Int16 dmCopies;
[System.Runtime.InteropServices.FieldOffset(56)]
Int16 dmDefaultSource;
[System.Runtime.InteropServices.FieldOffset(58)]
Int16 dmPrintQuality;
[System.Runtime.InteropServices.FieldOffset(44)]
public POINTL dmPosition;
[System.Runtime.InteropServices.FieldOffset(52)]
public Int32 dmDisplayOrientation;
[System.Runtime.InteropServices.FieldOffset(56)]
public Int32 dmDisplayFixedOutput;
[System.Runtime.InteropServices.FieldOffset(60)]
public short dmColor;
[System.Runtime.InteropServices.FieldOffset(62)]
public short dmDuplex;
[System.Runtime.InteropServices.FieldOffset(64)]
public short dmYResolution;
[System.Runtime.InteropServices.FieldOffset(66)]
public short dmTTOption;
[System.Runtime.InteropServices.FieldOffset(68)]
public short dmCollate;
[System.Runtime.InteropServices.FieldOffset(72)]
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = CCHFORMNAME)]
public string dmFormName;
[System.Runtime.InteropServices.FieldOffset(102)]
public Int16 dmLogPixels;
[System.Runtime.InteropServices.FieldOffset(104)]
public Int32 dmBitsPerPel;
[System.Runtime.InteropServices.FieldOffset(108)]
public Int32 dmPelsWidth;
[System.Runtime.InteropServices.FieldOffset(112)]
public Int32 dmPelsHeight;
[System.Runtime.InteropServices.FieldOffset(116)]
public Int32 dmDisplayFlags;
[System.Runtime.InteropServices.FieldOffset(116)]
public Int32 dmNup;
[System.Runtime.InteropServices.FieldOffset(120)]
public Int32 dmDisplayFrequency;
}
// See: https://msdn.microsoft.com/en-us/library/windows/desktop/dd183569(v=vs.85).aspx
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
internal struct DISPLAY_DEVICE
{
[MarshalAs(UnmanagedType.U4)]
public int cb;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]
public string DeviceName;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
public string DeviceString;
[MarshalAs(UnmanagedType.U4)]
public DisplayDeviceStateFlags StateFlags;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
public string DeviceID;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
public string DeviceKey;
}
// See: https://msdn.microsoft.com/de-de/library/windows/desktop/dd162807(v=vs.85).aspx
[StructLayout(LayoutKind.Sequential)]
internal struct POINTL
{
long x;
long y;
}
internal enum DISP_CHANGE : int
{
Successful = 0,
Restart = 1,
Failed = -1,
BadMode = -2,
NotUpdated = -3,
BadFlags = -4,
BadParam = -5,
BadDualView = -6
}
// http://www.pinvoke.net/default.aspx/Enums/DisplayDeviceStateFlags.html
[Flags()]
internal enum DisplayDeviceStateFlags : int
{
/// <summary>The device is part of the desktop.</summary>
AttachedToDesktop = 0x1,
MultiDriver = 0x2,
/// <summary>The device is part of the desktop.</summary>
PrimaryDevice = 0x4,
/// <summary>Represents a pseudo device used to mirror application drawing for remoting or other purposes.</summary>
MirroringDriver = 0x8,
/// <summary>The device is VGA compatible.</summary>
VGACompatible = 0x10,
/// <summary>The device is removable; it cannot be the primary display.</summary>
Removable = 0x20,
/// <summary>The device has more display modes than its output devices support.</summary>
ModesPruned = 0x8000000,
Remote = 0x4000000,
Disconnect = 0x2000000
}
// http://www.pinvoke.net/default.aspx/user32/ChangeDisplaySettingsFlags.html
[Flags()]
internal enum DisplaySettingsFlags : int
{
CDS_NONE = 0,
CDS_UPDATEREGISTRY = 0x00000001,
CDS_TEST = 0x00000002,
CDS_FULLSCREEN = 0x00000004,
CDS_GLOBAL = 0x00000008,
CDS_SET_PRIMARY = 0x00000010,
CDS_VIDEOPARAMETERS = 0x00000020,
CDS_ENABLE_UNSAFE_MODES = 0x00000100,
CDS_DISABLE_UNSAFE_MODES= 0x00000200,
CDS_RESET = 0x40000000,
CDS_RESET_EX = 0x20000000,
CDS_NORESET = 0x10000000
}
[Flags()]
internal enum DM : int
{
Orientation = 0x00000001,
PaperSize = 0x00000002,
PaperLength = 0x00000004,
PaperWidth = 0x00000008,
Scale = 0x00000010,
Position = 0x00000020,
NUP = 0x00000040,
DisplayOrientation = 0x00000080,
Copies = 0x00000100,
DefaultSource = 0x00000200,
PrintQuality = 0x00000400,
Color = 0x00000800,
Duplex = 0x00001000,
YResolution = 0x00002000,
TTOption = 0x00004000,
Collate = 0x00008000,
FormName = 0x00010000,
LogPixels = 0x00020000,
BitsPerPixel = 0x00040000,
PelsWidth = 0x00080000,
PelsHeight = 0x00100000,
DisplayFlags = 0x00200000,
DisplayFrequency = 0x00400000,
ICMMethod = 0x00800000,
ICMIntent = 0x01000000,
MediaType = 0x02000000,
DitherType = 0x04000000,
PanningWidth = 0x08000000,
PanningHeight = 0x10000000,
DisplayFixedOutput = 0x20000000
}
You can simply invoke the static Rotate-Function with the display number you want to rotate (Monitor 1=1, Monitor 2=2, etc.) and the degree you need. Like this:
Display.Rotate(1, Display.Orientations.DEGREES_CW_180);
There is also a little short-hand function ResetAllRotations() to reset all displays.
Regards