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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:///'.

pascal

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

Finding the default web browser

Every platform has a mechanism for its default web browser. 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:

pascal

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('Browser=',BrowserPath,' Params=',BrowserParams);
      v.Free;
    end;

This gives for example under Ubuntu (Linux):

pascal

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

Under Windows:

pascal

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

Under macOS:

pascal

Browser=/usr/bin/open Params="%s"

Starting the browser

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

pascal

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

TurboPower Internet Pro

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 the IPro tab on the Component Palette.

WebView4Delphi

WebView4Delphi allows to embed Chromium-based web browsers in your Delphi or Lazarus applications using the WebView2 runtime. It uses many of the tricks from CEF4Delphi and you will notice many similarities if you used it.

There are a few things pending like the "windowless mode".

TWebBrowser WebKit (macOS Cocoa)

TWebBrowser control is implemented only for the LCL Cocoa widgetset for macOS by wrapping the WebView class that's part of every Mac's WebKit framework. Note that by default macOS blocks calls to insecure HTTP sites. You can relax this restriction by setting the NSAllowsArbitraryLoads key in your application's Info.plist file, but for testing you might stick with HTTPS sites. This control does not add any bulk to your app and does not require installation of any additional libraries. Everything it needs is already on your Mac and is accessible via the FPC CocoaAll unit. Source.

QT Webkit

When using the Qt widgetset, you can use the Qt Webkit to embed a browser into a LCL form. Lazarus demo is 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.

HtmlViewer

The HtmlViewer component for Delphi and Lazarus, set consists of:

THtmlViewer
TFrameViewer
TFrameBrowser

fpCEF3

fpCEF3 is a Chromium Embedded Framework for Free Pascal.

CEF4Delphi

CEF4Delphi is updated Chromium Embedded Framework, which supports Lazarus.

GeckoPort

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

LazActiveX

LazActiveX allows to import MS Internet Explorer type library.

LazWebkit

LazWebkit is a project focused to provide browser and composer web content features for Lazarus IDE based projects. Currently it's implemented only for GTK2 widgetset.

Webbrowser

Starting a web browser to show a page/URL

OpenURL

Finding the default web browser

Starting the browser

Integrate web browser component in application

TurboPower Internet Pro

WebView4Delphi

TWebBrowser WebKit (macOS Cocoa)

QT Webkit

THtmlPort

HtmlViewer

fpCEF3

CEF4Delphi

GeckoPort

LazActiveX

LazWebkit

See also