What is the best way to make a Delphi Application completely full screen ?

Question

What is the best way to make a delphi application (delphi 2007 for win32 here) go completely full screen, removing the application border and covering windows task bar ?

I am looking for something similar to what IE does when you hit F11.

I wish this to be a run time option for the user not a design time decision by my good self.

As Mentioned in the accepted answer

BorderStyle := bsNone;

was part of the way to do it. Strangely I kept getting a E2010 Incompatible types: 'TFormBorderStyle' and 'TBackGroundSymbol' error when using that line (another type had 'bsNone' defined).

To overcome this I had to use :

BorderStyle := Forms.bsNone;

Answer 1

Maximize the form and hide the title bar. The maximize line is done from memory, but I'm pretty sure WindowState is the property you want.

There's also this article, but that seems too complicated to me.

procedure TForm1.FormCreate(Sender: TObject) ;
begin
   //maximize the window
   WindowState := wsMaximized;
   //hide the title bar
   SetWindowLong(Handle,GWL_STYLE,GetWindowLong(Handle,GWL_STYLE) and not WS_CAPTION);
   ClientHeight := Height;
end;

Edit: Here's a complete example, with "full screen" and "restore" options. I've broken out the different parts into little procedures for maximum clarity, so this could be greatly compressed into just a few lines.

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    btnGoFullScreen: TButton;
    btnNotFullScreen: TButton;
    btnShowTitleBar: TButton;
    btnHideTitleBar: TButton;
    btnQuit: TButton;
    procedure btnGoFullScreenClick(Sender: TObject);
    procedure btnShowTitleBarClick(Sender: TObject);
    procedure btnHideTitleBarClick(Sender: TObject);
    procedure btnNotFullScreenClick(Sender: TObject);
    procedure btnQuitClick(Sender: TObject);
  private
    SavedLeft : integer;
    SavedTop : integer;
    SavedWidth : integer;
    SavedHeight : integer;
    SavedWindowState : TWindowState;
    procedure FullScreen;
    procedure NotFullScreen;
    procedure SavePosition;
    procedure HideTitleBar;
    procedure ShowTitleBar;
    procedure RestorePosition;
    procedure MaximizeWindow;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.btnQuitClick(Sender: TObject);
begin
  Application.Terminate;
end;

procedure TForm1.btnGoFullScreenClick(Sender: TObject);
begin
  FullScreen;
end;

procedure TForm1.btnNotFullScreenClick(Sender: TObject);
begin
  NotFullScreen;
end;

procedure TForm1.btnShowTitleBarClick(Sender: TObject);
begin
  ShowTitleBar;
end;

procedure TForm1.btnHideTitleBarClick(Sender: TObject);
begin
  HideTitleBar;
end;

procedure TForm1.FullScreen;
begin
  SavePosition;
  HideTitleBar;
  MaximizeWindow;
end;

procedure TForm1.HideTitleBar;
begin
  SetWindowLong(Handle,GWL_STYLE,GetWindowLong(Handle,GWL_STYLE) and not WS_CAPTION);
  ClientHeight := Height;
end;

procedure TForm1.MaximizeWindow;
begin
  WindowState := wsMaximized;
end;

procedure TForm1.NotFullScreen;
begin
  RestorePosition;
  ShowTitleBar;
end;

procedure TForm1.RestorePosition;
begin
  //this proc uses what we saved in "SavePosition"
  WindowState := SavedWindowState;
  Top := SavedTop;
  Left := SavedLeft;
  Width := SavedWidth;
  Height := SavedHeight;
end;

procedure TForm1.SavePosition;
begin
  SavedLeft := Left;
  SavedHeight := Height;
  SavedTop := Top;
  SavedWidth := Width;
  SavedWindowState := WindowState;
end;

procedure TForm1.ShowTitleBar;
begin
  SetWindowLong(Handle,gwl_Style,GetWindowLong(Handle,gwl_Style) or ws_Caption or ws_border);
  Height := Height + GetSystemMetrics(SM_CYCAPTION);
  Refresh;
end;

end.

Answer 2

Well, this has always worked for me. Seems a bit simpler...

procedure TForm52.Button1Click(Sender: TObject);
begin
  BorderStyle := bsNone;
  WindowState := wsMaximized;
end;

Answer 3

A Google search turned up the following, additional methods:

(though I think I'd try Roddy's method first)

Manually fill the screen (from: About Delphi)

procedure TSomeForm.FormShow(Sender: TObject) ;
var
   r : TRect;
begin
   Borderstyle := bsNone;
   SystemParametersInfo
      (SPI_GETWORKAREA, 0, @r,0) ;
   SetBounds
     (r.Left, r.Top, r.Right-r.Left, r.Bottom-r.Top) ;
end;

Variation on a theme by Roddy

FormStyle := fsStayOnTop;
BorderStyle := bsNone;
Left := 0;
Top := 0;
Width := Screen.Width;
Height := Screen.Height;

The WinAPI way (by Peter Below from TeamB)

private  // in form declaration
    Procedure WMGetMinMaxInfo(Var msg: TWMGetMinMaxInfo);
      message WM_GETMINMAXINFO;

Procedure TForm1.WMGetMinMaxInfo(Var msg: TWMGetMinMaxInfo);
  Begin
    inherited;
    With msg.MinMaxInfo^.ptMaxTrackSize Do Begin
      X := GetDeviceCaps( Canvas.handle, HORZRES ) + (Width - ClientWidth);
      Y := GetDeviceCaps( Canvas.handle, VERTRES ) + (Height - ClientHeight
);
    End;
  End;

procedure TForm1.Button2Click(Sender: TObject);
Const
  Rect: TRect = (Left:0; Top:0; Right:0; Bottom:0);
  FullScreen: Boolean = False;
begin
  FullScreen := not FullScreen;  
  If FullScreen Then Begin
    Rect := BoundsRect;
    SetBounds(
      Left - ClientOrigin.X,
      Top - ClientOrigin.Y,
      GetDeviceCaps( Canvas.handle, HORZRES ) + (Width - ClientWidth),
      GetDeviceCaps( Canvas.handle, VERTRES ) + (Height - ClientHeight ));
  //  Label2.caption := IntToStr(GetDeviceCaps( Canvas.handle, VERTRES ));
  End
  Else
    BoundsRect := Rect;
end;

Answer 4

@kogus: I'd say it's a good idea to call ShowTitleBar in your form's destructor (if necessary) :)

Answer 5

I like to use Directx; you can even change resolution

Answer 6

How to constrain a sub-form within the Mainform like it was an MDI app., but without the headaches! (Note: The replies on this page helped me get this working, so that's why I posted my solution here)

private
{ Private declarations }
  StickyAt: Word;
  procedure WMWINDOWPOSCHANGING(Var Msg: TWMWINDOWPOSCHANGING); Message M_WINDOWPOSCHANGING;
  Procedure WMGetMinMaxInfo(Var msg: TWMGetMinMaxInfo); message WM_GETMINMAXINFO;

later...

    procedure TForm2.WMWINDOWPOSCHANGING(var Msg: TWMWINDOWPOSCHANGING);
    var
      A, B: Integer;
      iFrameSize: Integer;
      iCaptionHeight: Integer;
      iMenuHeight: Integer;
    begin

      iFrameSize := GetSystemMetrics(SM_CYFIXEDFRAME);
      iCaptionHeight := GetSystemMetrics(SM_CYCAPTION);
      iMenuHeight := GetSystemMetrics(SM_CYMENU);

      // inside the Mainform client area
      A := Application.MainForm.Left + iFrameSize;
      B := Application.MainForm.Top + iFrameSize + iCaptionHeight + iMenuHeight;

      with Msg.WindowPos^ do
      begin

        if x <= A + StickyAt then
          x := A;

        if x + cx >= A + Application.MainForm.ClientWidth - StickyAt then
          x := (A + Application.MainForm.ClientWidth) - cx + 1;

       if y <= B + StickyAt then
         y := B;

       if y + cy >= B + Application.MainForm.ClientHeight - StickyAt then
         y := (B + Application.MainForm.ClientHeight) - cy + 1;

      end;
end;

and yet more...

Procedure TForm2.WMGetMinMaxInfo(Var msg: TWMGetMinMaxInfo);
var
  iFrameSize: Integer;
  iCaptionHeight: Integer;
  iMenuHeight: Integer;
Begin
  inherited;
  iFrameSize := GetSystemMetrics(SM_CYFIXEDFRAME);
  iCaptionHeight := GetSystemMetrics(SM_CYCAPTION);
  iMenuHeight := GetSystemMetrics(SM_CYMENU);
  With msg.MinMaxInfo^.ptMaxPosition Do
  begin
    // position of top when maximised
    X := Application.MainForm.Left + iFrameSize + 1;
    Y := Application.MainForm.Top + iFrameSize + iCaptionHeight + iMenuHeight + 1;
  end;
  With msg.MinMaxInfo^.ptMaxSize Do
  Begin
     // width and height when maximized
     X := Application.MainForm.ClientWidth;
     Y := Application.MainForm.ClientHeight;
  End;
  With msg.MinMaxInfo^.ptMaxTrackSize Do
  Begin
     // maximum size when maximised
     X := Application.MainForm.ClientWidth;
     Y := Application.MainForm.ClientHeight;
  End;
  // to do: minimum size (maybe)
End;