{-----------------------------------------------------------------------------
The contents of this file are subject to the Mozilla Public License
Version 1.1 (the "License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
http://www.mozilla.org/MPL/MPL-1.1.html

Software distributed under the License is distributed on an "AS IS" basis,
WITHOUT WARRANTY OF ANY KIND, either expressed or implied. See the License for
the specific language governing rights and limitations under the License.

The Original Code is: JvDropDownForm, released on 2002-10-04.

The Initial Developer of the Original Code is Oliver Giesen [giesen att lucatec dott com]
Portions created by Oliver Giesen are Copyright (C) 2002 Lucatec GmbH.
All Rights Reserved.

Contributor(s):
  Andreas Hausladen

You may retrieve the latest version of this file at the Project JEDI's JVCL home page,
located at http://jvcl.sourceforge.net

Description:
  A generic container form to be displayed as dropdown below a TCustomEdit
  descendant.

  There's still plenty of room for improvement here.

Known Issues:
-----------------------------------------------------------------------------}
// $Id: JvDropDownForm.pas 11043 2006-11-26 07:21:48Z marquardt $

unit JvDropDownForm;

{$I jvcl.inc}

interface

uses
  {$IFDEF UNITVERSIONING}
  JclUnitVersioning,
  {$ENDIF UNITVERSIONING}
  Windows, Messages,
  {$IFDEF VisualCLX}
  Qt,
  {$ENDIF VisualCLX}
  Classes, Controls, StdCtrls, Forms,
  JvTypes, JvExForms;

type
  TJvCustomDropDownForm = class(TJvExCustomForm)
  private
    FEntering: Boolean;
    FCloseOnLeave: Boolean;
    FLeaving: Boolean;
    FOnKillFocus: TJvFocusChangeEvent;
    FOnSetFocus: TJvFocusChangeEvent;
  protected
    function GetEdit: TCustomEdit;
    procedure FocusSet(PrevWnd: THandle); override;
    procedure FocusKilled(NextWnd: THandle); override;
    procedure DoFocusSet(const APreviousControl: TWinControl); dynamic;
    procedure DoFocusKilled(const ANextControl: TWinControl); dynamic;
    procedure DoClose(var Action: TCloseAction); override;
    procedure DoShow; override;
    {$IFDEF VCL}
    procedure CreateParams(var AParams: TCreateParams); override;
    {$ENDIF VCL}
    {$IFDEF VisualCLX}
    function WidgetFlags: Integer; override;
    {$ENDIF VisualCLX}
    property Edit: TCustomEdit read GetEdit;
  public
    constructor Create(AOwner: TComponent); override;
    property CloseOnLeave: Boolean read FCloseOnLeave write FCloseOnLeave; // (ahuser) meight have no function under VisualCLX
    property Entering: Boolean read FEntering;
    property Leaving: Boolean read FLeaving;
    property OnSetFocus: TJvFocusChangeEvent read FOnSetFocus write FOnSetFocus;
    property OnKillFocus: TJvFocusChangeEvent read FOnKillFocus write FOnKillFocus;
  end;

{TODO : IsChildWindow should probably better be moved somewhere into the JCL}
function IsChildWindow(const AChild, AParent: THandle): Boolean;

{$IFDEF UNITVERSIONING}
const
  UnitVersioning: TUnitVersionInfo = (
    RCSfile: '$URL: https://jvcl.svn.sourceforge.net/svnroot/jvcl/tags/JVCL3_32/run/JvDropDownForm.pas $';
    Revision: '$Revision: 11043 $';
    Date: '$Date: 2006-11-26 08:21:48 +0100 (dim., 26 nov. 2006) $';
    LogPath: 'JVCL\run'
  );
{$ENDIF UNITVERSIONING}

implementation

uses
  SysUtils,
  JvConsts, JvResources, JvVCL5Utils;

function IsChildWindow(const AChild, AParent: THandle): Boolean;
var
  LParent: HWND;
begin
  {determines whether a window is the child (or grand^x-child) of another}
  LParent := AChild;
  if LParent = AParent then
    Result := False // (ahuser) a parent is no child of itself
  else
  begin
    while (LParent <> AParent) and (LParent <> NullHandle) do
      LParent := GetParent(LParent);
    Result := (LParent = AParent) and (LParent <> NullHandle);
  end;
end;

type
  TCustomEditAccessProtected = class(TCustomEdit);

constructor TJvCustomDropDownForm.Create(AOwner: TComponent);
begin
  if not (AOwner is TCustomEdit) then
    raise EJVCLException.CreateRes(@RsETJvCustomDropDownFormCreateOwnerMus);

  inherited CreateNew(AOwner);

  BorderIcons := [];
  {$IFDEF VCL}
  BorderStyle := bsNone;
  {$ENDIF VCL}
  {$IFDEF VisualCLX}
  BorderStyle := fbsNone;
  {$ENDIF VisualCLX}
  Font := TCustomEditAccessProtected(AOwner).Font;

  Position := poDesigned; // required for D2005
  FEntering := True;
  FLeaving := False;
  FCloseOnLeave := True;
end;

{$IFDEF VCL}
procedure TJvCustomDropDownForm.CreateParams(var AParams: TCreateParams);
begin
  inherited CreateParams(AParams);
  AParams.Style := AParams.Style or WS_BORDER;

  // Fixing the Window Ghosting "bug"
  // This also fixes mantis 3409 where the popup would not appear if its
  // associated control was placed on a form with fsStayOnTop form style.
  AParams.Style := Aparams.Style or WS_POPUP;
  if Assigned(Screen.ActiveForm) then
    AParams.WndParent := Screen.ActiveForm.Handle
  else
  if Assigned (Application.MainForm) then
    AParams.WndParent := Application.MainForm.Handle
  else
    AParams.WndParent := Application.Handle;
end;
{$ENDIF VCL}

{$IFDEF VisualCLX}
function TJvCustomDropDownForm.WidgetFlags: Integer;
begin
  Result := inherited WidgetFlags or Integer(WidgetFlags_WStyle_DialogBorder) or
    Integer(WidgetFlags_WType_Popup);
end;
{$ENDIF VisualCLX}

procedure TJvCustomDropDownForm.DoClose(var Action: TCloseAction);
begin
  Action := caFree;
  inherited DoClose(Action);
end;

procedure TJvCustomDropDownForm.DoShow;
var
  LScreenRect: TRect;
begin
  inherited DoShow;

  // Mantis 3357: Always reposition ourselves with respect to the owner
  // as it may have moved between two of our apparitions.
  with TWinControl(Owner) do
  begin
    Self.Left := ClientOrigin.X;
    Self.Top := ClientOrigin.Y + Height;
  end;

  {$IFDEF VCL}
  if Screen.MonitorCount > 0 then
  begin
    {$IFDEF COMPILER6_UP}
    LScreenRect := Monitor.WorkareaRect;
    {$ELSE}
    LScreenRect := GetMonitorWorkareaRect(Monitor);
    {$ENDIF COMPILER6_UP}
    if (Left + Width > LScreenRect.Right) then
      Left := LScreenRect.Right - Width;
    if (Top + Height > LScreenRect.Bottom) then
      Top := Self.Edit.ClientOrigin.Y - Height;
  end
  else
  {$ENDIF VCL}
  begin
    {$IFDEF VCL}
    if not SystemParametersInfo(SPI_GETWORKAREA, 0, @LScreenRect, 0) then
    {$ENDIF VCL}
      LScreenRect := Rect(0, 0, Screen.Width, Screen.Height);
    if (Left + Width > LScreenRect.Right) then
      Left := LScreenRect.Right - Width;
    if (Top + Height > LScreenRect.Bottom) then
      Top := Self.Edit.ClientOrigin.Y - Height;
  end;
end;

function TJvCustomDropDownForm.GetEdit: TCustomEdit;
begin
  Result := TCustomEdit(Owner);
end;

procedure TJvCustomDropDownForm.FocusKilled(NextWnd: THandle);
begin
  if IsChildWindow(NextWnd, Self.Handle) then
    inherited FocusKilled(NextWnd)
  else
  begin
    FLeaving := True;
    try
      inherited FocusKilled(NextWnd);
      DoFocusKilled(FindControl(NextWnd));
    finally
      FLeaving := False;
    end;
  end;
end;

procedure TJvCustomDropDownForm.DoFocusKilled(const ANextControl: TWinControl);
begin
  if Assigned(FOnKillFocus) then
    FOnKillFocus(Self, ANextControl);
  if CloseOnLeave then
    Close;
end;

procedure TJvCustomDropDownForm.FocusSet(PrevWnd: THandle);
begin
  if IsChildWindow(PrevWnd, Self.Handle) then
    inherited FocusSet(PrevWnd)
  else
  begin
    FEntering := True;
    try
      inherited FocusSet(PrevWnd);
      DoFocusSet(FindControl(PrevWnd));
    finally
      FEntering := False;
    end;
  end;
end;

procedure TJvCustomDropDownForm.DoFocusSet(const APreviousControl: TWinControl);
begin
  if Assigned(FOnSetFocus) then
    FOnSetFocus(Self, APreviousControl);
end;

{$IFDEF UNITVERSIONING}
initialization
  RegisterUnitVersion(HInstance, UnitVersioning);

finalization
  UnregisterUnitVersion(HInstance);
{$ENDIF UNITVERSIONING}

end.