source: trunk/doc/src/examples/fancybrowser.qdoc@ 651

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/*!
   \example webkit/fancybrowser
  \title Fancy Browser Example

    The Fancy Browser example shows how to use jQuery with QtWebKit to
    create a web browser with special effects and content
    manipulation.

    \image fancybrowser-example.png

    The application makes use of QWebFrame::evaluateJavaScript to 
    evaluate the jQuery JavaScript code. A QMainWindow with a QWebView
    as central widget builds up the browser itself. 

    \section1 MainWindow Class Definition

    The \c MainWindow class inherits QMainWindow. It implements a number of 
    slots to perform actions on both the application and on the web content. 

    \snippet examples/webkit/fancybrowser/mainwindow.h 1

    We also declare a QString that contains the jQuery, a QWebView
    that displays the web content, and a QLineEdit that acts as the
    address bar.

    \section1 MainWindow Class Implementation

    We start by implementing the constructor. 

    \snippet examples/webkit/fancybrowser/mainwindow.cpp 1

    The first part of the constructor sets the value of \c progress to
    0. This value will be used later in the code to visualize the
    loading of a webpage.

    Next, the jQuery library is loaded using a QFile and reading the file 
    content. The jQuery library is a JavaScript library that provides different 
    functions for manipulating HTML. 

    \snippet examples/webkit/fancybrowser/mainwindow.cpp 2

    The second part of the constructor creates a QWebView and connects
    slots to the views signals. Furthermore, we create a QLineEdit as
    the browsers address bar. We then set the horizontal QSizePolicy
    to fill the available area in the browser at all times. We add the
    QLineEdit to a QToolbar together with a set of navigation actions
    from QWebView::pageAction.  

    \snippet examples/webkit/fancybrowser/mainwindow.cpp 3

    The third and last part of the constructor implements two QMenus and assigns
    a set of actions to them. The last line sets the QWebView as the central 
    widget in the QMainWindow.

    \snippet examples/webkit/fancybrowser/mainwindow.cpp 4

    When the page is loaded, \c adjustLocation() updates the address
    bar; \c adjustLocation() is triggered by the \c loadFinished()
    signal in QWebView. In \c changeLocation() we create a QUrl
    object, and then use it to load the page into the QWebView. When
    the new web page has finished loading, \c adjustLocation() will be
    run once more to update the address bar.

    \snippet examples/webkit/fancybrowser/mainwindow.cpp 5

    \c adjustTitle() sets the window title and displays the loading
    progress. This slot is triggered by the \c titleChanged() signal
    in QWebView. 

    \snippet examples/webkit/fancybrowser/mainwindow.cpp 6

    When a web page has loaded, \c finishLoading() is triggered by the 
    \c loadFinished() signal in QWebView. \c finishLoading() then updates the 
    progress in the title bar and calls \c evaluateJavaScript() to evaluate the
    jQuery library. This evaluates the JavaScript against the current web page. 
    What that means is that the JavaScript can be viewed as part of the content 
    loaded into the QWebView, and therefore needs to be loaded every time a new 
    page is loaded. Once the jQuery library is loaded, we can start executing 
    the different jQuery functions in the browser.

    The rotateImages() function is then called explicitely to make sure
    that the images of the newly loaded page respect the state of the toggle
    action.

    \snippet examples/webkit/fancybrowser/mainwindow.cpp 7

    The first jQuery-based function, \c highlightAllLinks(), is designed to  
    highlight all links in the current webpage. The JavaScript code looks 
    for web elements named \e {a}, which is the tag for a hyperlink. 
    For each such element, the background color is set to be yellow by
    using CSS. 

    \snippet examples/webkit/fancybrowser/mainwindow.cpp 8
    
    The \c rotateImages() function rotates the images on the current
    web page. Webkit supports CSS transforms and this JavaScript code 
    looks up all \e {img} elements and rotates the images 180 degrees
    and then back again. 

    \snippet examples/webkit/fancybrowser/mainwindow.cpp 9

    The remaining four methods remove different elements from the current web 
    page. \c removeGifImages() removes all Gif images on the page by looking up 
    the \e {src} attribute of all the elements on the web page. Any element with 
    a \e {gif} file as its source is removed. \c removeInlineFrames() removes all 
    \e {iframe} or inline elements. \c removeObjectElements() removes all 
    \e {object} elements, and \c removeEmbeddedElements() removes any elements 
    such as plugins embedded on the page using the \e {embed} tag.

*/