Webbrowser

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This page summarizes various ways to display HTML pages from a Pascal program, ranging from calling an external browser to adding a component capable of rendering the html page into a form.

Starting a web browser to show a page/URL

OpenURL

OpenURL is simplest way of opening URLs in general. This procedure will detect the default web browser and open URL from parameter in it. It can be used for mail addresses of the form 'mailto:aname@AnAddress?subject=:::A subject line', web addresses 'http://' and files 'file:///'.

uses LCLIntf;
...
OpenURL('http://www.lazarus.freepascal.org');

Finding the default webbrowser

Every platform has a mechanism for its default platform. The LCL unit lazhelphtml contains a class THTMLBrowserHelpViewer to start a web browser for the LCL help system. You can use its method FindDefaultBrowser to find the default browser and the parameter to start. For example:

uses 
  Classes, ..., LCLProc, LazHelpHTML;
 
...
 
implementation
 
procedure TMainForm.Button1Click(Sender: TObject);
var
  v: THTMLBrowserHelpViewer;
  BrowserPath, BrowserParams: string;
begin
  v:=THTMLBrowserHelpViewer.Create(nil);
  v.FindDefaultBrowser(BrowserPath,BrowserParams);
  debugln(['Path=',BrowserPath,' Params=',BrowserParams]);
  v.Free;
end;

This gives for example under Ubuntu (Linux):

Browser=/usr/bin/xdg-open Params=%s

Under Windows you can get:

Browser=C:\windows\system32\rundll32.exe Params=url.dll,FileProtocolHandler %s

Starting the browser

Once you know the command line and parameters you can use TProcessUTF8 to start the browser:

uses 
  Classes, ..., LCLProc, LazHelpHTML, UTF8Process;
 
...
 
implementation
 
procedure TMainForm.Button1Click(Sender: TObject);
var
  v: THTMLBrowserHelpViewer;
  BrowserPath, BrowserParams: string;
  p: LongInt;
  URL: String;
  BrowserProcess: TProcessUTF8;
begin
  v:=THTMLBrowserHelpViewer.Create(nil);
  try
    v.FindDefaultBrowser(BrowserPath,BrowserParams);
    debugln(['Path=',BrowserPath,' Params=',BrowserParams]);
 
    URL:='http://www.lazarus.freepascal.org';
    p:=System.Pos('%s', BrowserParams);
    System.Delete(BrowserParams,p,2);
    System.Insert(URL,BrowserParams,p);
 
    // start browser
    BrowserProcess:=TProcessUTF8.Create(nil);
    try
      BrowserProcess.CommandLine:=BrowserPath+' '+BrowserParams;
      BrowserProcess.Execute;
    finally
      BrowserProcess.Free;
    end;
  finally
    v.Free;
  end;
end;

Integrate web browser component in application

Using the Turbopower internet pro control

Lazarus provides the package TurboPowerIPro (lazarus/components/turbopower_ipro/turbopoweripro.lpk) with the following features:

  • It contains a control to put onto a form. When you install the package in the IDE, you get some new components in the palette, so you can drop them onto a form just like any LCL control.
  • It is written completely in Pascal and therefore works on all platforms out of the box without any extra installation.
  • You have the full control, what files/urls are opened.
  • It does not have all the features of a full webbrowser. No multimedia stuff, javascript or flash. This must be implemented by you.

There are some examples in lazarus/components/turbopower_ipro/examples demonstrating how to open a local html file with some images, hyperlinks and history buttons.

see IPro tab on the Component Palette.

QT Webkit

When using the Qt WidgetSet, you can use the Qt WebKit to embed a browser into a LCL form.

Lazarus LCL/Qt WebKit Demo available on FPC Qt4 Binding Web Page

THtmlPort

THtmlPort is a Lazarus/Free Pascal version of Dave Baldwin's HTML Components, including THtmlViewer, TFrameViewer and TFrameBrowser.

fpCEF3

Chromium Embedded Framework for Free Pascal

GeckoPort

GeckoPort is a Lazarus/Free Pascal version of Takanori Ito's Gecko SDK for Delphi, including the TGeckoBrowser component.

LazActiveX

Import Internet Explorer Type Library.

LazWebKit

Webkit for GTK2 lazwebkit

See also