unit uVirtualTouchKeyboard;

{$IFDEF FPC}{$MODE Delphi}{$ENDIF}

// This unit uses undocumented Windows interfaces!

// ITipInvocation, IInputHostManagerBroker and IImmersiveShellBroker are
// available in Windows 8, 10 and 11 but the code in this unit works best in a
// fully updated Windows 10 or 11 system.

// Some ITipInvocation code examples use alternative ways to detect when the
// virtual keyboard is visible but the tests showed that using
// IInputHostManagerBroker is much safer and easier.

// The code in this unit is a translation of these examples :
// https://stackoverflow.com/questions/38774139/show-touch-keyboard-tabtip-exe-in-windows-10-anniversary-edition
// https://fire-monkey.ru/topic/5621-%D1%81%D0%B5%D0%BD%D1%81%D0%BE%D1%80%D0%BD%D0%B0%D1%8F-%D0%BA%D0%BB%D0%B0%D0%B2%D0%B8%D0%B0%D1%82%D1%83%D1%80%D0%B0-windows/
// https://stackoverflow.com/questions/50623154/c-sharp-wpf-windows-10-1803-touchkeyboard-unreliable-issue-prism-clickonce
// https://github.com/TransposonY/GestureSign/blob/master/GestureSign.CorePlugins/TouchKeyboard/TouchKeyboard.cs
// https://stackoverflow.com/questions/47187216/determine-if-windows-10-touch-keyboard-is-visible-or-hidden

interface

uses
 {$IFDEF FPC}
 Windows, Classes, SysUtils, SHFolder, ActiveX, ShellAPI, jwatlhelp32;
 {$ELSE}
 Winapi.Windows, System.Classes, System.SysUtils, Winapi.SHFolder,
 System.Threading, Winapi.ActiveX, Winapi.ShellAPI, Winapi.TlHelp32;
 {$ENDIF}


const                                                                           
  CLSID_UIHostNoLaunch        : TGUID = '{4CE576FA-83DC-4F88-951C-9D0782B4E376}';
  IID_ITipInvocation          : TGUID = '{37C994E7-432B-4834-A2F7-DCE1F13B834B}';  
  
  CLSID_ImmersiveShellBroker  : TGUID = '{228826af-02e1-4226-a9e0-99a855e455a6}';
  IID_IImmersiveShellBroker   : TGUID = '{9767060c-9476-42e2-8f7b-2f10fd13765c}';   
  IID_IInputHostManagerBroker : TGUID = '{2166ee67-71df-4476-8394-0ced2ed05274}';

  TABTIP_PROCNAME = 'TabTip.exe';

type
  TDisplayMode = type integer;
  
  ITipInvocation = interface
    ['{37C994E7-432B-4834-A2F7-DCE1F13B834B}']
    procedure Toggle(WND: HWND); safecall;
  end;

  IInputHostManagerBroker = interface
    ['{2166ee67-71df-4476-8394-0ced2ed05274}']
    procedure GetIhmLocation(out rect : TRect; out mode : TDisplayMode); safecall; 
  end;

  IImmersiveShellBroker = interface
    ['{9767060c-9476-42e2-8f7b-2f10fd13765c}']
    procedure Dummy; safecall;
    function GetInputHostManagerBroker : IInputHostManagerBroker; safecall;
  end;

  /// <summary>
  /// Implementation of the virtual touch keyboard available in Windows using
  /// the undocumented ITipInvocation, IInputHostManagerBroker and
  /// IImmersiveShellBroker interfaces.
  /// </summary>
  TVirtualTouchKeyboard = class
    protected
      function GetTabTipPath : string;
      function GetCommonProgramFilesPath : string;
      function GetVisible : boolean;
      function GetExecuting : boolean;

      function ProcessExists(const aExeFileName : string) : Boolean;
      function GetIhmLocation(var aRect : TRect) : boolean;

      property TabTipPath              : string   read GetTabTipPath;
      property CommonProgramFilesPath  : string   read GetCommonProgramFilesPath;

    public
      /// <summary>
      /// Show the virtual keyboard. It opens TabTip.exe if it's not running.
      /// </summary>
      procedure Show;
      /// <summary>
      /// Hide the virtual keyboard.
      /// </summary>
      procedure Hide;
      /// <summary>
      /// Toggle virtual keyboard visibility.
      /// </summary>
      function  Toggle : boolean;
      /// <summary>
      /// Execute TabTip.exe
      /// </summary>
      function  ExecuteTabTip : boolean;
      /// <summary>
      /// Returns true if the virtual keyboard is visible.
      /// </summary>
      property Visible    : boolean  read GetVisible;
      /// <summary>
      /// Returns true if TabTip.exe is running.
      /// </summary>
      property Executing  : boolean  read GetExecuting;
  end;


implementation


function TVirtualTouchKeyboard.GetTabTipPath : string;
const
  TABTIP_SUBPATH = 'microsoft shared\ink\' + TABTIP_PROCNAME;
begin
  Result := CommonProgramFilesPath + TABTIP_SUBPATH;

  if not(FileExists(Result)) then
    begin
      Result := 'C:\Program Files\Common Files\' + TABTIP_SUBPATH;

      if not(FileExists(Result)) then
        Result := '';
    end;
end;

function TVirtualTouchKeyboard.GetCommonProgramFilesPath: string;
var
  TempBuffer: array [0..pred(MAX_PATH)] of Char;
begin
  FillChar(TempBuffer, MAX_PATH * SizeOf(Char), 0);

  if succeeded(SHGetFolderPath(0, CSIDL_PROGRAM_FILES_COMMON, 0, 0, @TempBuffer[0])) then
    Result := IncludeTrailingPathDelimiter(TempBuffer)
   else
    Result := '';
end;

function TVirtualTouchKeyboard.GetVisible : boolean;
var
  TempRect : TRect;
begin
  Result := GetIhmLocation(TempRect) and (TempRect.Width > 0) and (TempRect.Height > 0);
end;

function TVirtualTouchKeyboard.GetExecuting : boolean;
begin
  Result := ProcessExists(TABTIP_PROCNAME);
end;

function TVirtualTouchKeyboard.ProcessExists(const aExeFileName: string): Boolean;
var
  TempHandle  : THandle;
  TempProcess : TProcessEntry32;
begin
  Result     := False;
  TempHandle := CreateToolHelp32SnapShot(TH32CS_SNAPPROCESS, 0);

  if (TempHandle <> INVALID_HANDLE_VALUE) then
    try
      ZeroMemory(@TempProcess, SizeOf(TProcessEntry32));
      TempProcess.dwSize := Sizeof(TProcessEntry32);

      if Process32First(TempHandle, TempProcess) then
        repeat
          if (CompareText(ExtractFileName(TempProcess.szExeFile), aExeFileName) = 0) then
            begin
              Result := True;
              break;
            end;
        until not(Process32Next(TempHandle, TempProcess));
    finally
      CloseHandle(TempHandle);
    end;
end;

function TVirtualTouchKeyboard.ExecuteTabTip : boolean;
var
  TempPath : string;
begin
  TempPath := TabTipPath;
  Result   := (length(TempPath) > 0) and
              (ShellExecute(0, 'open', PChar(TempPath + #0), nil, nil, SW_SHOWNORMAL) > 32);
end;

function TVirtualTouchKeyboard.Toggle : boolean;
var
  TempInvocation : ITipInvocation;
  TempResult     : HRESULT;
begin
  Result     := False;
  TempResult := CoCreateInstance(CLSID_UIHostNoLaunch,
                                 nil,
                                 CLSCTX_INPROC_HANDLER or CLSCTX_LOCAL_SERVER,
                                 IID_ITipInvocation,
                                 TempInvocation);

  if succeeded(TempResult) then
    begin
      TempInvocation.Toggle(GetDesktopWindow);
      Result := True;
    end;
end;         

function TVirtualTouchKeyboard.GetIhmLocation(var aRect : TRect) : boolean;
var
  TempShellBroker : IImmersiveShellBroker;
  TempMgrBroker : IInputHostManagerBroker;
  TempResult : HRESULT;
  TempRect : TRect;
  TempMode : TDisplayMode;
begin
  Result     := False;
  TempResult := CoCreateInstance(CLSID_ImmersiveShellBroker,
                                 nil,
                                 CLSCTX_INPROC_HANDLER or CLSCTX_LOCAL_SERVER,
                                 IID_IImmersiveShellBroker,
                                 TempShellBroker);

  if succeeded(TempResult) then
    begin
      TempMgrBroker := TempShellBroker.GetInputHostManagerBroker;
      TempMgrBroker.GetIhmLocation(TempRect, TempMode);
      aRect  := TempRect;
      Result := True;
    end;
end;

procedure TVirtualTouchKeyboard.Show;
begin
  if not(Visible) then
    begin
      if Executing then
        Toggle
       else
        if ExecuteTabTip then
          begin
            {$IFDEF FPC}
            sleep(500);
            Toggle;
            {$ELSE}
            TThread.ForceQueue(nil,
              procedure
              begin
                Toggle;
              end, 500);
            {$ENDIF}
          end;
    end;
end;

procedure TVirtualTouchKeyboard.Hide;
begin
  if Visible then 
    Toggle;
end;    

end.