Rolling-up-a-form


            The standard behaviour for double clicking a title bar is to maximize/restore the form. The following class changes the double click action to add a new effect which is RollUp/Restore.
Copy the following unit and place it in a directory which is recognised by delphi's search path (i.e. \Delphi\5.0\Lib\)
unit OrckaForm;
interface
{$B-}
uses
 Messages, Forms, Classes;
type
 TOrckaForm = class(TForm)
 private
 FOldHeight: Longint;
 FRollUp, FRolledUp: Boolean;
 protected
 procedure WMNCLDblClick(var Msg: TMessage); message WM_NCLBUTTONDBLCLK;
 procedure WMGetMinMaxInfo(var Msg: TMessage); message WM_GETMINMAXINFO;
 public
 constructor Create(AOwner: TComponent); override;
 property RollUp: Boolean read FRollUp write FRollUp;
 end;
implementation
uses Windows;
procedure TOrckaForm.WMNCLDblClick(var Msg: TMessage);
begin
 if (Msg.wParam = HTCAPTION) and (FRollUp) then
 begin
 if FRolledUp then
 begin
 FRolledUp := False;
 Height := FOldHeight;
 end else
 begin
 FRolledUp := True;
 FOldHeight := Height;
 Height := 0
 end;
 end else
 inherited;
end;
constructor TOrckaForm.Create(AOwner: TComponent);
begin
 inherited Create(AOwner);
 FOldHeight := Height;
 FRollUp := True;
 FRolledUp := False;
end;
procedure TOrckaForm.WMGetMinMaxInfo(var Msg: TMessage);
begin
 inherited;
 if FRolledUp then
 pMinMaxInfo(Msg.lParam)^.ptMaxTrackSize.y := Height;
end;
end.
To use the form create a new form which will look something like..
unit Unit3;
interface
uses
 Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs;
type
 TForm3 = class(TForm)
 private
 { Private declarations }
Add OrckaForm to the uses clause and change the following line
TForm3 = class(TForm)
to
TForm3 = class(TOrckaForm)
run your project, whenever you double click the title the form will roll up/restore.
Examples Delphi
