WinGDI Get All supported Monitor Resolutions

getresolution.fsx

#nowarn "9"
open System
open System.Runtime.InteropServices

[<StructLayout(LayoutKind.Sequential)>]
type DEVMODEInfo = struct
    [<MarshalAs(UnmanagedType.ByValTStr, SizeConst=32)>]
    [<DefaultValue>] val mutable dmDeviceName : string
    [<DefaultValue>] val mutable dmSpecVersion: int16; 
    [<DefaultValue>] val mutable dmDriverVersion: int16; 
    [<DefaultValue>] val mutable dmSize: int16; 
    [<DefaultValue>] val mutable dmDriverExtra: int16; 
    [<DefaultValue>] val mutable dmFields: int; 
    // [<DefaultValue>] val mutable dmOrientation: int16; 
    // [<DefaultValue>] val mutable dmPaperSize: int16; 
    // [<DefaultValue>] val mutable dmPaperLength: int16; 
    // [<DefaultValue>] val mutable dmPaperWidth: int16; 
    // [<DefaultValue>] val mutable dmScale: int16; 
    // [<DefaultValue>] val mutable dmCopies: int16; 
    // [<DefaultValue>] val mutable dmDefaultSource: int16; 
    // [<DefaultValue>] val mutable dmPrintQuality: int16;
    [<DefaultValue>] val mutable dmPositionX: int;
    [<DefaultValue>] val mutable dmPositionY: int;
    [<DefaultValue>] val mutable dmDisplayOrientation: int;
    [<DefaultValue>] val mutable dmDisplayFixedOutput: int;        
    
    [<DefaultValue>] val mutable dmColor: int16; 
    [<DefaultValue>] val mutable dmDuplex: int16; 
    [<DefaultValue>] val mutable dmYResolution: int16; 
    [<DefaultValue>] val mutable dmTTOption: int16; 
    [<DefaultValue>] val mutable dmCollate: int16; 
    [<MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)>] 
    [<DefaultValue>] val mutable dmFormName : string;
    [<DefaultValue>] val mutable dmLogPixels: int16; 
    [<DefaultValue>] val mutable dmBitsPerPel: int16; 
    [<DefaultValue>] val mutable dmPelsWidth: int; 
    [<DefaultValue>] val mutable dmPelsHeight: int; 
    [<DefaultValue>] val mutable dmDisplayFlags: int; 
    [<DefaultValue>] val mutable dmDisplayFrequency: int; 
    [<DefaultValue>] val mutable dmICMMethod: int; 
    [<DefaultValue>] val mutable dmICMIntent: int; 
    [<DefaultValue>] val mutable dmMediaType: int; 
    [<DefaultValue>] val mutable dmDitherType: int; 
    [<DefaultValue>] val mutable dmReserved1: int; 
    [<DefaultValue>] val mutable dmReserved2: int; 
    [<DefaultValue>] val mutable dmPanningWidth: int; 
    [<DefaultValue>] val mutable dmPanningHeight: int;
    new (device: string, form: string) = { }
end

[<StructLayout(LayoutKind.Sequential)>]
type DisplayDeviceInfo = struct
    static member size = Marshal.SizeOf<DisplayDeviceInfo>()
    [<DefaultValue>] val mutable cb: int;
    [<MarshalAs(UnmanagedType.ByValTStr, SizeConst=32)>]
    [<DefaultValue>] val mutable deviceName : string
    [<MarshalAs(UnmanagedType.ByValArray, SizeConst=128)>]
    [<DefaultValue>] val mutable deviceString : char[]
    [<DefaultValue>] val mutable stateFlags: int;
    [<MarshalAs(UnmanagedType.ByValArray, SizeConst=128)>]
    [<DefaultValue>] val mutable deviceID : char[]
    [<MarshalAs(UnmanagedType.ByValArray, SizeConst=128)>]
    [<DefaultValue>] val mutable deviceKey : char[]
end

[<DllImport("User32.dll")>] 
extern bool EnumDisplaySettings(string displayName, int mode, DEVMODEInfo& output);

[<DllImport("User32.dll")>]
extern bool EnumDisplayDevices(string device, int devNum, DisplayDeviceInfo& displayDevice, int flags);

let getdevice name i = 
   let mutable device = DisplayDeviceInfo(cb=DisplayDeviceInfo.size)
   match EnumDisplayDevices(name, i, &device, 1) with | false -> None | _ -> Some(device)

[<Flags>]
type MonitorFlags =
    | Active = 1
    | MultiDriver = 2
    | Primary = 4
    | MirroringDriver = 8
    | VGACompatible = 16
    | Removable = 32
    | ModesPruned = 0x8000000
    | Remote = 0x4000000
    | Disconnect = 0x2000000

type DisplayOrientation =
    | Default = 0
    | Rotate90 = 1
    | Rotate180 = 2
    | Rotate270 = 3

type DisplayFixedOutput =
    | Default = 0
    | Stretch = 1
    | Center = 2
    
type DisplayMode(dm : DEVMODEInfo) =
    member val Name = dm.dmDeviceName
    member val Height = dm.dmPelsHeight
    member val Width = dm.dmPelsWidth
    member val BitsPerPel = dm.dmBitsPerPel
    member val FPS = dm.dmDisplayFrequency
    member val Orientation : DisplayOrientation = enum dm.dmDisplayOrientation
    member val FixedOutput : DisplayFixedOutput = enum dm.dmDisplayFixedOutput
    override this.ToString() =
        String.concat ", " [for p in typeof<DisplayMode>.GetProperties() -> sprintf "%s: %O" p.Name (p.GetValue(this, null))]
        
let getDisplayInfo display index =
    let mutable dm =
        DEVMODEInfo(
            dmDeviceName = String.replicate 30 " ",
            dmFormName = String.replicate 30 " ",
            dmSize = int16 sizeof<DEVMODEInfo>)
    match EnumDisplaySettings(display, index, &dm) with | false -> None | _ -> Some(DisplayMode(dm))

type Monitor(name, flags) =
    member val Name : string = name
    member val Flags : MonitorFlags = enum flags
    
type DisplayDevice(name, flags) =
    member val Name : string = name
    member val Flags : MonitorFlags = enum flags
    member this.Monitors
      with get () = List.unfold (fun i -> getdevice name i |> Option.map (fun dw -> (Monitor(dw.deviceName, dw.stateFlags), i + 1))) 0
    member this.Modes
      with get() = List.unfold (fun i -> getDisplayInfo name i |> Option.map (fun dw -> (dw, i + 1))) 0          
    static member All
      with get() = List.unfold (fun i -> getdevice null i |> Option.map (fun dw -> (DisplayDevice(dw), i + 1))) 0
    new(info : DisplayDeviceInfo) = DisplayDevice(info.deviceName, info.stateFlags)

for dv in DisplayDevice.All do
    printfn "%O %A" dv.Name dv.Flags
    for m in dv.Monitors do
        printfn "  %A %A" m.Name m.Flags
    for m in dv.Modes do
        printfn "%O" m