unit X11_Displays;

{$M+}

interface
uses X11_Objects, X11, type_fixes, X11_Screens, xlib;

type
  // that really shouldn't be.
  TDisplay = class(system.TObject)
  private
    fScreens : TScreenArray;
    fHandle : PDisplay;
    fBOwnsDisplay : Boolean;
  protected
    function GetScreen(aIndex : TCardinal) : X11_Screens.TScreen;
    function GetScreenCount : TCardinal;
    //function ISHMExtension.GetPixmapFormat = GetSHMPixmapFormat : ?;
    function GetSHM : ISHMExtension;
    function GetDefaultScreen : TCardinal;
    procedure DeleteUnderlyingObject; // override;
    function GetHandle() : PDisplay;
  public
    destructor Destroy(); override;
  published
    constructor Open;
  public
    property Screens[index : TCardinal] : X11_Screens.TScreen read GetScreen;
  published
    property ScreenCount : TCardinal read GetScreenCount;
    property DefaultScreen : TCardinal read GetDefaultScreen; // index into Screens[].
 
    // TODO externalize this?
    //property SHMPixmapFormat : ?;
    
    procedure Flush; // eew...    
    property SHM : ISHMExtension read GetSHM;
    class function Default : TDisplay; // argh.
  public
    property Handle : PDisplay read GetHandle;
  end;
  
implementation
uses sysutils, X11_SHM_Extension;

var 
  fDefaultDisplay : TDisplay = nil;
  
class function TDisplay.Default : TDisplay; // argh.
begin
  if not Assigned(fDefaultDisplay) then
    fDefaultDisplay := TDisplay.Open();
    
  Result := fDefaultDisplay;
end;

constructor TDisplay.Open;
begin
  //SetLength(fScreens, 0);
  inherited Create;
  fBOwnsDisplay := True;
  fHandle := XOpenDisplay(nil);
end;

procedure TDisplay.DeleteUnderlyingObject;
begin
  if Assigned(fHandle) and fBOwnsDisplay then begin
    XCloseDisplay(fHandle);
    fHandle := nil;
  end;
end;

function TDisplay.GetHandle() : PDisplay;
begin
  Result := fHandle;
end;

destructor TDisplay.Destroy();
begin
  DeleteUnderlyingObject();
  inherited Destroy();
end;

function TDisplay.GetDefaultScreen : TCardinal;
begin
  Result := xlib.DefaultScreen(fHandle);
end;

function TDisplay.GetScreen(aIndex : TCardinal) : X11_Screens.TScreen;
var
  XScreen : xlib.PScreen;
begin
  if Length(fScreens) < GetScreenCount then
    SetLength(fScreens, GetScreenCount); // FIXME zero the area?
    
  if not Assigned(fScreens[aIndex]) then begin
    XScreen := xlib.ScreenOfDisplay(fHandle, aIndex);
    fScreens[aIndex] := X11_Screens.TScreen.Reuse(Handle, XScreen, False);
  end;
  
  Result := fScreens[aIndex];
end;

function TDisplay.GetScreenCount : TCardinal;
begin
  Result := xlib.ScreenCount(Handle);
end;

procedure TDisplay.Flush; // eew...    
begin
end;

function TDisplay.GetSHM : ISHMExtension;
begin
  Result := TSHMExtension.Open(Handle);
end;

finalization
  FreeAndNil(fDefaultDisplay);
  
end.