diff options
Diffstat (limited to 'examples/webenginewidgets/printme/doc/src/printme.qdoc')
| -rw-r--r-- | examples/webenginewidgets/printme/doc/src/printme.qdoc | 55 |
1 files changed, 21 insertions, 34 deletions
diff --git a/examples/webenginewidgets/printme/doc/src/printme.qdoc b/examples/webenginewidgets/printme/doc/src/printme.qdoc index d05d5147b..91aecf6de 100644 --- a/examples/webenginewidgets/printme/doc/src/printme.qdoc +++ b/examples/webenginewidgets/printme/doc/src/printme.qdoc @@ -1,32 +1,9 @@ -/**************************************************************************** -** -** Copyright (C) 2019 The Qt Company Ltd. -** Contact: https://www.qt.io/licensing/ -** -** This file is part of the documentation of the Qt Toolkit. -** -** $QT_BEGIN_LICENSE:FDL$ -** Commercial License Usage -** Licensees holding valid commercial Qt licenses may use this file in -** accordance with the commercial license agreement provided with the -** Software or, alternatively, in accordance with the terms contained in -** a written agreement between you and The Qt Company. For licensing terms -** and conditions see https://www.qt.io/terms-conditions. For further -** information use the contact form at https://www.qt.io/contact-us. -** -** GNU Free Documentation License Usage -** Alternatively, this file may be used under the terms of the GNU Free -** Documentation License version 1.3 as published by the Free Software -** Foundation and appearing in the file included in the packaging of -** this file. Please review the following information to ensure -** the GNU Free Documentation License version 1.3 requirements -** will be met: https://www.gnu.org/licenses/fdl-1.3.html. -** $QT_END_LICENSE$ -** -****************************************************************************/ +// Copyright (C) 2019 The Qt Company Ltd. +// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only /*! - \example webenginewidgets/printme + \example webenginewidgets/printme + \examplecategory {Web Technologies} \title WebEngine Widgets PrintMe Example \ingroup webengine-widgetexamples \brief Demonstrates how to print web pages using Qt WebEngine Widgets. @@ -66,8 +43,8 @@ \section1 Print Handler - In the \c{PrintHandler} function, we first implement \c{printPreview()}, - where we instantiate \l{QPrinter} together with \l{QPrintPreviewDialog}. + In the \c{PrintHandler} class, we first implement \c{printPreview()}, + where we instantiate \l{QPrintPreviewDialog}. We need the \l{QPrintPreviewDialog::paintRequested} handle to generate a set of preview pages. @@ -77,16 +54,26 @@ Now we can implement the \c{PrintHandler::printDocument()} slot, which is called in response to the \l{QPrintPreviewDialog::paintRequested} signal. + To do actual painting on a printer, we call the \l QWebEngineView::print() + function. Printing is an async operation in Chromium, but not in Qt, so we + run a local event loop using \l{QEventLoop::exec()} to make sure printing + is done before returning. User input is blocked, since clicking on a button + while we're waiting for the print to finish can mess up the internal state + and cause a crash. \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. + To get notified about the result of printing job, we implement + \c{PrintHandler::printFinished()} slot as handler of + \l QWebEngineView::printFinished() signal. We check for \c{success} and + report any errors that occurred. Finally, we call \l{QEventLoop::quit()} + to exit out of the local event loop. + + \quotefromfile webenginewidgets/printme/printhandler.cpp + \skipto PrintHandler::printFinished( + \printuntil /^\}/ The last function we implement, \c{PrintHandler::print()}, is trivial, because it simply opens \l{QPrintDialog} and calls the previously |