QWebPage Class Reference
[QtWebKit module]

Using QWebPage in a Widget-less Environment

Before you begin painting a QWebPage object, you need to set the size of the viewport by calling setViewportSize(). Then, you invoke the main frame's render function (QWebFrame::render()). An example of this is shown in the code snippet below.

Suppose we have a Thumbnail class as follows:

 class Thumbnailer : public QObject
 {
     Q_OBJECT

 public:
     Thumbnailer(const QUrl &url);

 signals:
     void finished();

 private slots:
     void render();

 private:
     QWebPage page;

 };

The Thumbnail's constructor takes in a url. We connect our QWebPage object's loadFinished() signal to our private slot, render().

 Thumbnailer::Thumbnailer(const QUrl &url)
 {
     page.mainFrame()->load(url);
     connect(&page, SIGNAL(loadFinished(bool)),
         this, SLOT(render()));
 }

The render() function shows how we can paint a thumbnail using a QWebPage object.

 void Thumbnailer::render()
 {
     page.setViewportSize(page.mainFrame()->contentsSize());
     QImage image(page.viewportSize(), QImage::Format_ARGB32);
     QPainter painter(&image);

     page.mainFrame()->render(&painter);
     painter.end();

     QImage thumbnail = image.scaled(400, 400);
     thumbnail.save("thumbnail.png");

     emit finished();
 }

We begin by setting the viewportSize and then we instantiate a QImage object, image, with the same size as our viewportSize. This image is then sent as a parameter to painter. Next, we render the contents of the main frame and its subframes into painter. Finally, we save the scaled image.

See also QWebFrame.

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