CEF4Delphi/demos/Delphi_VCL/TabbedBrowser2/uMainForm.pas

// ************************************************************************
// ***************************** CEF4Delphi *******************************
// ************************************************************************
//
// CEF4Delphi is based on DCEF3 which uses CEF 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 <20> 2021 Salvador Diaz 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 uMainForm;

{$I cef.inc}

interface

uses
  {$IFDEF DELPHI16_UP}
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics, System.SyncObjs,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.ComCtrls, Vcl.ToolWin, Vcl.Buttons, Vcl.ExtCtrls,
  {$ELSE}
  Windows, Messages, SysUtils, Variants, Classes, Graphics, SyncObjs,
  Controls, Forms, Dialogs, ComCtrls, ToolWin, Buttons, ExtCtrls,
  {$ENDIF}
  uCEFApplication, uCEFInterfaces, uCEFTypes, uCEFConstants, uChildForm;

const
  CEF_INITIALIZED      = WM_APP + $A50;
  CEF_DESTROYTAB       = WM_APP + $A51;
  CEF_CREATENEXTCHILD  = WM_APP + $A52;
  CEF_CHILDDESTROYED   = WM_APP + $A53;

  HOMEPAGE_URL        = 'https://www.google.com';
  DEFAULT_TAB_CAPTION = 'New tab';

type
  TMainForm = class(TForm)
    BrowserPageCtrl: TPageControl;
    ButtonPnl: TPanel;
    AddTabBtn: TSpeedButton;
    RemoveTabBtn: TSpeedButton;

    procedure AddTabBtnClick(Sender: TObject);
    procedure RemoveTabBtnClick(Sender: TObject);

    procedure FormShow(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
    procedure FormDestroy(Sender: TObject);

  protected
    FChildForm       : TChildForm;
    FCriticalSection : TCriticalSection;
    FCanClose        : boolean;
    FClosing         : boolean;  // Set to True in the CloseQuery event.
    FLastTabID       : cardinal; // Used by NextTabID to generate unique tab IDs

    function  GetNextTabID : cardinal;
    function  GetPopupChildCount : integer;

    procedure EnableButtonPnl;
    function  CloseAllBrowsers : boolean;
    procedure CloseTab(aIndex : integer);

    procedure CEFInitializedMsg(var aMessage : TMessage); message CEF_INITIALIZED;
    procedure DestroyTabMsg(var aMessage : TMessage); message CEF_DESTROYTAB;
    procedure CreateNextChildMsg(var aMessage : TMessage); message CEF_CREATENEXTCHILD;
    procedure ChildDestroyedMsg(var aMessage : TMessage); message CEF_CHILDDESTROYED;
    procedure WMMove(var aMessage : TWMMove); message WM_MOVE;
    procedure WMMoving(var aMessage : TMessage); message WM_MOVING;
    procedure WMEnterMenuLoop(var aMessage: TMessage); message WM_ENTERMENULOOP;
    procedure WMExitMenuLoop(var aMessage: TMessage); message WM_EXITMENULOOP;

    property  NextTabID       : cardinal   read GetNextTabID;
    property  PopupChildCount : integer    read GetPopupChildCount;

  public
    function  CreateClientHandler(var windowInfo : TCefWindowInfo; var client : ICefClient; const targetFrameName : string; const popupFeatures : TCefPopupFeatures) : boolean;
  end;

var
  MainForm: TMainForm;

procedure CreateGlobalCEFApp;

implementation

{$R *.dfm}

uses
  uBrowserTab;

// This demo shows how to use a TPageControl with TFrames that include
// CEF4Delphi browsers.

// Instead of a regular TTabSheet we use a custom TBrowserTab class that
// inherits from TTabSheet and instead of a regular TFrame we use a custom
// TBrowserFrame class that inherits from TFrame.

// To create a new tab you need to call TBrowserTab.CreateBrowser in the last
// step to create all the browser components and initialize the browser.

// To close a tab you have to call TBrowserTab.CloseBrowser and wait for a
// CEF_DESTROYTAB message that includes TBrowserTab.TabID in TMessage.wParam.
// Then you find the tab with that unique TabID and free it.

// TBrowserFrame has all the usual code to close CEF4Delphi browsers following
// a similar destruction sequence than the MiniBrowser demo :
//
// 1. TBrowserTab.CloseBrowser calls TChromium.CloseBrowser which triggers the
//    TChromium.OnClose event.
// 2. TChromium.OnClose sends a CEF_DESTROY message to destroy CEFWindowParent1
//    in the main thread, which triggers the TChromium.OnBeforeClose event.
// 3. TChromium.OnBeforeClose executes the TBrowserFrame.OnBrowserDestroyed
//    event which will be used in TBrowserTab to send a CEF_DESTROYTAB message
//    to the main form to free the tab.

// This demo also uses custom forms to open popup browsers in the same way as
// the PopupBrowser2 demo. Please, read the code comments in that demo for all
// details about handling the custom child forms.

// To close safely this demo you must close all the browser tabs first following
// this steps :
//
// 1. FormCloseQuery sets CanClose to FALSE and calls CloseAllBrowsers and FClosing
//    is set to TRUE.
// 2. Each tab will send a CEF_DESTROYTAB message to the main form to free that tab.
// 3. Each child form will send a CEF_CHILDDESTROYED message to the main form.
// 3. When TPageControl has no tabs and all the child forms are also closed then we
//    can set FCanClose to TRUE and send a WM_CLOSE message to the main form to
//    close the application.

procedure GlobalCEFApp_OnContextInitialized;
begin
  if (MainForm <> nil) and MainForm.HandleAllocated then
    PostMessage(MainForm.Handle, CEF_INITIALIZED, 0, 0);
end;

procedure CreateGlobalCEFApp;
begin
  GlobalCEFApp                      := TCefApplication.Create;
  GlobalCEFApp.cache                := 'cache';
  GlobalCEFApp.OnContextInitialized := GlobalCEFApp_OnContextInitialized;
end;

procedure TMainForm.EnableButtonPnl;
begin
  if not(ButtonPnl.Enabled) then
    begin
      ButtonPnl.Enabled := True;
      Caption           := 'Tabbed Browser 2';
      cursor            := crDefault;
      if (BrowserPageCtrl.PageCount = 0) then AddTabBtn.Click;
    end;
end;

function TMainForm.GetNextTabID : cardinal;
begin
  inc(FLastTabID);
  Result := FLastTabID;
end;

function TMainForm.GetPopupChildCount : integer;
var
  i        : integer;
  TempForm : TCustomForm;
begin
  Result := 0;
  i      := pred(screen.CustomFormCount);

  while (i >= 0) do
    begin
      TempForm := screen.CustomForms[i];

      // Only count the fully initialized child forms and not the one waiting to be used.

      if (TempForm is TChildForm) and
         TChildForm(TempForm).ClientInitialized then
        inc(Result);

      dec(i);
    end;
end;

procedure TMainForm.AddTabBtnClick(Sender: TObject);
var
  TempNewTab : TBrowserTab;
begin
  TempNewTab             := TBrowserTab.Create(self, NextTabID, DEFAULT_TAB_CAPTION);
  TempNewTab.PageControl := BrowserPageCtrl;

  BrowserPageCtrl.ActivePageIndex := pred(BrowserPageCtrl.PageCount);

  TempNewTab.CreateBrowser(HOMEPAGE_URL);
end;

procedure TMainForm.CEFInitializedMsg(var aMessage : TMessage);
begin
  EnableButtonPnl;

  if (FChildForm = nil) then
    TChildForm.Create(self);
end;

procedure TMainForm.DestroyTabMsg(var aMessage : TMessage);
var
  i : integer;
  TempTab : TBrowserTab;
begin
  i := 0;
  while (i < BrowserPageCtrl.PageCount) do
    begin
      TempTab := TBrowserTab(BrowserPageCtrl.Pages[i]);

      if (TempTab.TabID = aMessage.wParam) then
        begin
          TempTab.Free;
          break;
        end
       else
        inc(i);
    end;

  if FClosing and (PopupChildCount = 0) and (BrowserPageCtrl.PageCount = 0) then
    begin
      FCanClose := True;
      PostMessage(Handle, WM_CLOSE, 0, 0);
    end;
end;

procedure TMainForm.ChildDestroyedMsg(var aMessage : TMessage);
begin
  if FClosing and (PopupChildCount = 0) and (BrowserPageCtrl.PageCount = 0) then
    begin
      FCanClose := True;
      PostMessage(Handle, WM_CLOSE, 0, 0);
    end;
end;

procedure TMainForm.CreateNextChildMsg(var aMessage : TMessage);
begin
  try
    FCriticalSection.Acquire;

    if (FChildForm <> nil) then
      begin
        FChildForm.ApplyPopupFeatures;
        FChildForm.Show;
      end;

    FChildForm := TChildForm.Create(self);
  finally
    FCriticalSection.Release;
  end;
end;

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

  if not(FClosing) then
    begin
      FClosing          := True;
      ButtonPnl.Enabled := False;

      if not(CloseAllBrowsers) then
        begin
          FCanClose := True;
          PostMessage(Handle, WM_CLOSE, 0, 0);
        end;
    end;
end;

procedure TMainForm.FormCreate(Sender: TObject);
begin
  FCanClose        := False;
  FClosing         := False;
  FLastTabID       := 0;
  FChildForm       := nil;
  FCriticalSection := TCriticalSection.Create;
end;

procedure TMainForm.FormDestroy(Sender: TObject);
begin
  FreeAndNil(FCriticalSection);
end;

procedure TMainForm.FormShow(Sender: TObject);
begin
  if (GlobalCEFApp <> nil) and GlobalCEFApp.GlobalContextInitialized then
    begin
      EnableButtonPnl;

      if (FChildForm = nil) then
        FChildForm := TChildForm.Create(self);
    end;
end;

procedure TMainForm.RemoveTabBtnClick(Sender: TObject);
begin
  CloseTab(BrowserPageCtrl.ActivePageIndex);
end;

function TMainForm.CloseAllBrowsers : boolean;
var
  i        : integer;
  TempForm : TCustomForm;
begin
  Result := False;
  i      := pred(screen.CustomFormCount);

  while (i >= 0) do
    begin
      TempForm := screen.CustomForms[i];

      if (TempForm is TChildForm) and
         TChildForm(TempForm).ClientInitialized and
         not(TChildForm(TempForm).Closing) then
        begin
          PostMessage(TempForm.Handle, WM_CLOSE, 0, 0);
          Result := True;
        end;

      dec(i);
    end;

  i := pred(BrowserPageCtrl.PageCount);

  while (i >= 0) do
    begin
      TBrowserTab(BrowserPageCtrl.Pages[i]).CloseBrowser;
      Result := True;
      dec(i);
    end;
end;

procedure TMainForm.CloseTab(aIndex : integer);
begin
  if (aIndex >= 0) and (aIndex < BrowserPageCtrl.PageCount) then
    TBrowserTab(BrowserPageCtrl.Pages[aIndex]).CloseBrowser;
end;

procedure TMainForm.WMMove(var aMessage : TWMMove);
var
  i : integer;
begin
  inherited;

  i := 0;
  while (i < BrowserPageCtrl.PageCount) do
    begin
      TBrowserTab(BrowserPageCtrl.Pages[i]).NotifyMoveOrResizeStarted;
      inc(i);
    end;
end;

procedure TMainForm.WMMoving(var aMessage : TMessage);
var
  i : integer;
begin
  inherited;

  i := 0;
  while (i < BrowserPageCtrl.PageCount) do
    begin
      TBrowserTab(BrowserPageCtrl.Pages[i]).NotifyMoveOrResizeStarted;
      inc(i);
    end;
end;

procedure TMainForm.WMEnterMenuLoop(var aMessage: TMessage);
begin
  inherited;

  if (aMessage.wParam = 0) and (GlobalCEFApp <> nil) then
    GlobalCEFApp.OsmodalLoop := True;
end;

procedure TMainForm.WMExitMenuLoop(var aMessage: TMessage);
begin
  inherited;

  if (aMessage.wParam = 0) and (GlobalCEFApp <> nil) then
    GlobalCEFApp.OsmodalLoop := False;
end;

function TMainForm.CreateClientHandler(var   windowInfo      : TCefWindowInfo;
                                       var   client          : ICefClient;
                                       const targetFrameName : string;
                                       const popupFeatures   : TCefPopupFeatures) : boolean;
begin
  try
    FCriticalSection.Acquire;

    Result := (FChildForm <> nil) and
              FChildForm.CreateClientHandler(windowInfo, client, targetFrameName, popupFeatures) and
              PostMessage(Handle, CEF_CREATENEXTCHILD, 0, 0);
  finally
    FCriticalSection.Release;
  end;
end;

end.