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| |
| /*! |
| \example webenginewidgets/printme |
| \title WebEngine Widgets PrintMe Example |
| \ingroup webengine-widgetexamples |
| \brief Demonstrates how to print web pages using Qt WebEngine Widgets. |
| |
| \image printme-example.png |
| |
| \e PrintMe demonstrates how to use the \l{QWebEnginePage} and |
| \l{QPrintDialog} classes to print a web page. Further, it shows how |
| to implement print preview by using the \l{QPrintPreviewDialog} class. |
| For completeness, it also illustrates how to trigger a printing request |
| within JavaScript. |
| |
| \include examples-run.qdocinc |
| |
| \section1 Simple HTML Page |
| |
| In this example, we create an internal HTML page that is added as a resource |
| collection file (.qrc). The page shows only a small HTML message box that |
| explains how to trigger printing by using keyboard shortcuts or clicking a |
| button. The button has the JavaScript \c{onclick} event attribute that calls |
| the JavaScript \c{window.print()} function. |
| |
| \quotefromfile webenginewidgets/printme/data/index.html |
| \skipto <html |
| \printuntil html> |
| |
| \section1 Main Function |
| |
| In the \c main function, we first instantiate a QWebEngineView and set the |
| URL to our internal HTML page. Next, we create a \c PrintHandler instance |
| and pass the requested page. For convenience, we also create keyboard |
| shortcuts that can be used to call a print dialog or print preview dialog. |
| |
| \quotefromfile webenginewidgets/printme/main.cpp |
| \skipto QWebEngineView view |
| \printto return |
| |
| \section1 Print Handler |
| |
| In the \c{PrintHandler} function, we first implement \c{printPreview()}, |
| where we instantiate \l{QPrinter} together with \l{QPrintPreviewDialog}. |
| We need the \l{QPrintPreviewDialog::paintRequested} handle to generate a |
| set of preview pages. |
| |
| \quotefromfile webenginewidgets/printme/printhandler.cpp |
| \skipto PrintHandler::printPreview( |
| \printuntil /^\}/ |
| |
| Now we can implement the \c{PrintHandler::printDocument()} slot, which is |
| called in response to the \l{QPrintPreviewDialog::paintRequested} signal. |
| |
| \quotefromfile webenginewidgets/printme/printhandler.cpp |
| \skipto PrintHandler::printDocument( |
| \printuntil /^\}/ |
| |
| To do actual painting on a printer, we call the \l{QWebEnginePage::print()} |
| function. Because this call blocks the main event loop, we need to create |
| a local one. We begin the local event loop by calling |
| \l{QEventLoop::exec()}. When the local event loop terminates, |
| we check for \c{result} and report any errors that occurred. |
| |
| The last function we implement, \c{PrintHandler::print()}, is trivial, |
| because it simply opens \l{QPrintDialog} and calls the previously |
| implemented \c{PrintHandler::printDocument()}. |
| |
| \quotefromfile webenginewidgets/printme/printhandler.cpp |
| \skipto PrintHandler::print( |
| \printuntil /^\}/ |
| */ |
