CEF4Delphi/demos/Lazarus_Linux_GTK2/TabbedBrowser2/uMainForm.pas
2023-01-07 15:53:04 +01:00

317 lines
8.8 KiB
ObjectPascal

// ************************************************************************
// ***************************** 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 © 2023 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;
{$mode objfpc}{$H+}
{$I cef.inc}
interface
uses
LCLIntf, LCLType, LMessages, Messages, SysUtils, Variants, Classes, Graphics,
Controls, Forms, Dialogs, ComCtrls, ToolWin, Buttons, ExtCtrls,
uCEFApplication, uCEFTypes, uCEFConstants;
const
CEF_INITIALIZED = $100;
CEF_DESTROYTAB = $101;
HOMEPAGE_URL = 'https://www.google.com';
DEFAULT_TAB_CAPTION = 'New tab';
type
{ TMainForm }
TMainForm = class(TForm)
BrowserPageCtrl: TPageControl;
ButtonPnl: TPanel;
AddTabBtn: TSpeedButton;
RemoveTabBtn: TSpeedButton;
procedure AddTabBtnClick(Sender: TObject);
procedure RemoveTabBtnClick(Sender: TObject);
procedure FormActivate(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
protected
// Variables to control when can we destroy the form safely
FCanClose : boolean;
FClosing : boolean;
FLastTabID : cardinal; // Used by NextTabID to generate unique tab IDs
function GetNextTabID : cardinal;
procedure EnableButtonPnl;
function CloseAllTabs : boolean;
procedure CloseTab(aIndex : integer);
procedure NotifyMoveOrResizeStarted;
procedure BrowserInitializedMsg(Data: PtrInt);
procedure BrowserDestroyedTabMsg(Data: PtrInt);
procedure WMMove(var aMessage: TLMMove); message LM_MOVE;
procedure WMSize(var aMessage: TLMSize); message LM_SIZE;
procedure WMWindowPosChanged(var aMessage: TLMWindowPosChanged); message LM_WINDOWPOSCHANGED;
property NextTabID : cardinal read GetNextTabID;
public
procedure SendCompMessage(aMsg : cardinal; aData : PtrInt = 0);
end;
var
MainForm: TMainForm = nil;
procedure CreateGlobalCEFApp;
implementation
{$R *.lfm}
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 with the TBrowserTab.TabID value.
// Then you find the tab with that unique TabID and free it.
// Most of the TChromium events store the parameter values in a set of class
// fields which are protected by a critial section and then they call
// TBrowserFrame.SendCompMessage to execute the GUI code in the main thread.
// 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 sets aAction to cbaClose which trigges 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.
// To close safely this demo you must close all the browser tabs first following
// this steps :
//
// 1. FormCloseQuery sets CanClose to FALSE and calls CloseAllTabs and FClosing
// is set to TRUE.
// 2. Each tab will send a CEF_DESTROYTAB message to free that tab.
// 3. When TPageControl has no tabs then we can set FCanClose to TRUE and
// close the main form.
procedure GlobalCEFApp_OnContextInitialized;
begin
if (MainForm <> nil) and MainForm.Showing and MainForm.Focused then
MainForm.SendCompMessage(CEF_INITIALIZED);
end;
procedure CreateGlobalCEFApp;
begin
GlobalCEFApp := TCefApplication.Create;
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;
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.FormActivate(Sender: TObject);
begin
if (GlobalCEFApp <> nil) and GlobalCEFApp.GlobalContextInitialized then
EnableButtonPnl;
end;
procedure TMainForm.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
begin
CanClose := FCanClose;
if not(FClosing) then
begin
FClosing := True;
ButtonPnl.Enabled := False;
if not(CloseAllTabs) then
begin
FCanClose := True;
CanClose := True;
end;
end;
end;
procedure TMainForm.FormCreate(Sender: TObject);
begin
FCanClose := False;
FClosing := False;
FLastTabID := 0;
end;
procedure TMainForm.RemoveTabBtnClick(Sender: TObject);
begin
CloseTab(BrowserPageCtrl.ActivePageIndex);
end;
function TMainForm.CloseAllTabs : boolean;
var
i : integer;
begin
Result := False;
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.NotifyMoveOrResizeStarted;
var
i : integer;
begin
i := 0;
while (i < BrowserPageCtrl.PageCount) do
begin
TBrowserTab(BrowserPageCtrl.Pages[i]).NotifyMoveOrResizeStarted;
inc(i);
end;
end;
procedure TMainForm.WMMove(var aMessage : TLMMove);
begin
inherited;
NotifyMoveOrResizeStarted;
end;
procedure TMainForm.WMSize(var aMessage: TLMSize);
begin
inherited;
NotifyMoveOrResizeStarted;
end;
procedure TMainForm.WMWindowPosChanged(var aMessage: TLMWindowPosChanged);
begin
inherited;
NotifyMoveOrResizeStarted;
end;
procedure TMainForm.BrowserInitializedMsg(Data: PtrInt);
begin
EnableButtonPnl;
end;
procedure TMainForm.BrowserDestroyedTabMsg(Data: PtrInt);
var
i : integer;
TempTab : TBrowserTab;
begin
i := 0;
while (i < BrowserPageCtrl.PageCount) do
begin
TempTab := TBrowserTab(BrowserPageCtrl.Pages[i]);
if (TempTab.TabID = cardinal(Data)) then
begin
TempTab.Free;
break;
end
else
inc(i);
end;
if FClosing and (BrowserPageCtrl.PageCount = 0) then
begin
FCanClose := True;
close;
end;
end;
procedure TMainForm.SendCompMessage(aMsg : cardinal; aData : PtrInt);
begin
case aMsg of
CEF_INITIALIZED : Application.QueueAsyncCall(@BrowserInitializedMsg, aData);
CEF_DESTROYTAB : Application.QueueAsyncCall(@BrowserDestroyedTabMsg, aData);
end;
end;
end.