CEF4Delphi/demos/ToolBoxBrowser/uChildForm.pas

// ************************************************************************
// ***************************** CEF4Delphi *******************************
// ************************************************************************
//
// CEF4Delphi is based on DCEF3 which uses CEF3 to embed a chromium-based
// browser in Delphi applications.
//
// The original license of DCEF3 still applies to CEF4Delphi.
//
// For more information about CEF4Delphi visit :
//         https://www.briskbard.com/index.php?lang=en&pageid=cef
//
//        Copyright © 2017 Salvador Díaz Fau. All rights reserved.
//
// ************************************************************************
// ************ vvvv Original license and comments below vvvv *************
// ************************************************************************
(*
 *                       Delphi Chromium Embedded 3
 *
 * Usage allowed under the restrictions of the Lesser GNU General Public License
 * or alternatively the restrictions of the Mozilla Public License 1.1
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
 * the specific language governing rights and limitations under the License.
 *
 * Unit owner : Henri Gourvest <hgourvest@gmail.com>
 * Web site   : http://www.progdigy.com
 * Repository : http://code.google.com/p/delphichromiumembedded/
 * Group      : http://groups.google.com/group/delphichromiumembedded
 *
 * Embarcadero Technologies, Inc is not permitted to use or redistribute
 * this source code without explicit permission.
 *
 *)

unit uChildForm;

{$I cef.inc}

interface

uses
  {$IFDEF DELPHI16_UP}
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.ExtCtrls,
  System.UITypes,
  {$ELSE}
  Windows, Messages, SysUtils, Variants, Classes, Graphics,
  Controls, Forms, Dialogs, ExtCtrls,
  {$ENDIF}
  uCEFChromium, uCEFWindowParent, uCEFInterfaces, uCEFConstants, uCEFTypes, uMainForm;

type
  TChildForm = class(TForm)
    CEFWindowParent1: TCEFWindowParent;
    Chromium1: TChromium;
    procedure FormShow(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
    procedure FormDestroy(Sender: TObject);
    procedure Chromium1AfterCreated(Sender: TObject;
      const browser: ICefBrowser);
    procedure Chromium1Close(Sender: TObject; const browser: ICefBrowser;
      out Result: Boolean);
    procedure Chromium1PreKeyEvent(Sender: TObject;
      const browser: ICefBrowser; const event: PCefKeyEvent; osEvent: PMsg;
      out isKeyboardShortcut, Result: Boolean);
    procedure Chromium1KeyEvent(Sender: TObject;
      const browser: ICefBrowser; const event: PCefKeyEvent; osEvent: PMsg;
      out Result: Boolean);
    procedure Chromium1BeforeClose(Sender: TObject;
      const browser: ICefBrowser);

  private
    // Variables to control when can we destroy the form safely
    FCanClose : boolean;  // Set to True in TChromium.OnBeforeClose
    FClosing  : boolean;  // Set to True in the CloseQuery event.
    FHomepage : string;

  protected
    procedure BrowserCreatedMsg(var aMessage : TMessage); message CEFBROWSER_CREATED;
    procedure BrowserDestroyMsg(var aMessage : TMessage); message CEFBROWSER_DESTROY;
    procedure WMMove(var aMessage : TWMMove); message WM_MOVE;
    procedure WMMoving(var aMessage : TMessage); message WM_MOVING;

    procedure HandleKeyUp(const aMsg : TMsg; var aHandled : boolean);
    procedure HandleKeyDown(const aMsg : TMsg; var aHandled : boolean);

  public
    property Closing   : boolean    read FClosing;
    property Homepage  : string     read FHomepage    write FHomepage;
  end;

implementation

{$R *.dfm}

// Destruction steps
// =================
// 1. FormCloseQuery calls TChromium.CloseBrowser
// 2. TChromium.OnClose sends a CEFBROWSER_DESTROY message to destroy CEFWindowParent1 and Chromium1 in the main thread.
// 3. TChromium.OnBeforeClose sets FCanClose := True and sends WM_CLOSE to the form.

procedure TChildForm.Chromium1AfterCreated(Sender: TObject; const browser: ICefBrowser);
begin
  PostMessage(Handle, CEFBROWSER_CREATED, 0, 0);
end;

procedure TChildForm.Chromium1BeforeClose(Sender: TObject; const browser: ICefBrowser);
begin
  FCanClose := True;
  PostMessage(Handle, WM_CLOSE, 0, 0);
end;

procedure TChildForm.Chromium1Close(Sender: TObject; const browser: ICefBrowser; out Result: Boolean);
begin
  PostMessage(Handle, CEFBROWSER_DESTROY, 0, 0);
end;

procedure TChildForm.Chromium1KeyEvent(Sender: TObject;
  const browser: ICefBrowser; const event: PCefKeyEvent; osEvent: PMsg;
  out Result: Boolean);
var
  TempMsg : TMsg;
begin
  Result := False;

  if (event <> nil) and (osEvent <> nil) then
    case osEvent.Message of
      WM_KEYUP :
        begin
          TempMsg := osEvent^;
          HandleKeyUp(TempMsg, Result);
        end;

      WM_KEYDOWN :
        begin
          TempMsg := osEvent^;
          HandleKeyDown(TempMsg, Result);
        end;
    end;
end;

procedure TChildForm.HandleKeyUp(const aMsg : TMsg; var aHandled : boolean);
var
  TempMessage : TMessage;
  TempKeyMsg  : TWMKey;
begin
  TempMessage.Msg     := aMsg.message;
  TempMessage.wParam  := aMsg.wParam;
  TempMessage.lParam  := aMsg.lParam;
  TempKeyMsg          := TWMKey(TempMessage);

  if (TempKeyMsg.CharCode = VK_ESCAPE) then
    begin
      aHandled := True;
      PostMessage(Handle, WM_CLOSE, 0, 0);
    end;
end;

procedure TChildForm.HandleKeyDown(const aMsg : TMsg; var aHandled : boolean);
var
  TempMessage : TMessage;
  TempKeyMsg  : TWMKey;
begin
  TempMessage.Msg     := aMsg.message;
  TempMessage.wParam  := aMsg.wParam;
  TempMessage.lParam  := aMsg.lParam;
  TempKeyMsg          := TWMKey(TempMessage);

  if (TempKeyMsg.CharCode = VK_ESCAPE) then aHandled := True;
end;

procedure TChildForm.Chromium1PreKeyEvent(Sender: TObject;
  const browser: ICefBrowser; const event: PCefKeyEvent; osEvent: PMsg;
  out isKeyboardShortcut, Result: Boolean);
begin
  Result := False;

  if (event <> nil) and
     (event.kind in [KEYEVENT_KEYDOWN, KEYEVENT_KEYUP]) and
     (event.windows_key_code = VK_ESCAPE) then
    isKeyboardShortcut := True;
end;

procedure TChildForm.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  Action := caFree;
end;

procedure TChildForm.FormCloseQuery(Sender: TObject;
  var CanClose: Boolean);
begin
  CanClose := FCanClose;

  if not(FClosing) then
    begin
      FClosing := True;
      Chromium1.CloseBrowser(True);
    end;
end;

procedure TChildForm.FormCreate(Sender: TObject);
begin
  FCanClose := False;
  FClosing  := False;
end;

procedure TChildForm.FormDestroy(Sender: TObject);
begin
  // Tell the main form that a child has been destroyed.
  // The main form will check if this was the last child to close itself
  PostMessage(MainForm.Handle, CEFBROWSER_CHILDDESTROYED, 0, 0);
end;

procedure TChildForm.FormShow(Sender: TObject);
begin
  Chromium1.CreateBrowser(CEFWindowParent1, '');
end;

procedure TChildForm.WMMove(var aMessage : TWMMove);
begin
  inherited;

  if (Chromium1 <> nil) then Chromium1.NotifyMoveOrResizeStarted;
end;

procedure TChildForm.WMMoving(var aMessage : TMessage);
begin
  inherited;

  if (Chromium1 <> nil) then Chromium1.NotifyMoveOrResizeStarted;
end;

procedure TChildForm.BrowserCreatedMsg(var aMessage : TMessage);
begin
  Chromium1.LoadURL(FHomepage);
end;

procedure TChildForm.BrowserDestroyMsg(var aMessage : TMessage);
begin
  CEFWindowParent1.Free;
  Chromium1.Free;
end;

end.