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authorDavid Boddie <dboddie@trolltech.com>2009-03-26 16:46:24 (GMT)
committerDavid Boddie <dboddie@trolltech.com>2009-03-26 16:46:24 (GMT)
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commit 23e30464792f7e403e0815775eb7acbaad975238 Author: David Boddie <dboddie@trolltech.com> Date: Thu Mar 26 17:41:20 2009 +0100 Doc: Added some basic documentation for the QSvgGenerator class. Task-number: 244944 Reviewed-by: TrustMe commit f84c1806d2ba40a61499584562d754f65d43f854 Merge: 8a42be7... 213d922... Author: David Boddie <dboddie@trolltech.com> Date: Thu Mar 26 16:59:14 2009 +0100 Merge branch '4.5' of ../qt-45 into qt/4.5 commit 8a42be789077de45f8fd9f13afd177798df7495e Author: David Boddie <dboddie@trolltech.com> Date: Thu Mar 26 16:58:33 2009 +0100 Doc: Added missing pieces for the SVG Generator example. Reviewed-by: David Boddie <dboddie@trolltech.com>
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+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain
+** additional rights. These rights are described in the Nokia Qt LGPL
+** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
+** package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*!
+ \example painting/svggenerator
+ \title SVG Generator Example
+
+ The SVG Generator example shows how to add SVG file export to applications.
+
+ \image svggenerator-example.png
+
+ Scalable Vector Graphics (SVG) is an XML-based language for describing
+ two-dimensional vector graphics. Qt provides classes for rendering and
+ generating SVG drawings. This example allows the user to create a simple
+ picture and save it to an SVG file.
+
+ The example consists of two classes: \c Window and \c DisplayWidget.
+
+ The \c Window class contains the application logic and constructs the user
+ interface from a Qt Designer \c{.ui} file as described in the
+ \l{Using a Designer .ui File in Your Application#The Multiple Inheritance Approach}{Qt Designer manual}.
+ It also contains the code to write an SVG file.
+
+ The \c DisplayWidget class performs all the work of painting a picture on
+ screen. Since we want the SVG to resemble this picture as closely as
+ possible, we make this code available to the \c Window class so that it can
+ be used to generate SVG files.
+
+ \section1 The DisplayWidget Class
+
+ The \c DisplayWidget class displays a drawing consisting of a selection of
+ elements chosen by the user. These are defined using \c Shape and
+ \c Background enums that are included within the class definition:
+
+ \snippet examples/painting/svggenerator/displaywidget.h DisplayWidget class definition
+
+ Much of this class is used to configure the appearance of the drawing. The
+ \c paintEvent() and \c paint() functions are most relevant to the purpose
+ of this example, so we will describe these here and leave the reader to
+ look at the source code for the example to see how shapes and colors are
+ handled.
+
+ We reimplement the QWidget::paintEvent() function to display the drawing
+ on screen:
+
+ \snippet examples/painting/svggenerator/displaywidget.cpp paint event
+
+ Here, we only construct a QPainter object, begin painting on the device
+ and set a render hint for improved output quality before calling the
+ \c paint() function to perform the painting itself. When this returns,
+ we close the painter and return.
+
+ The \c paint() function is designed to be used for different painting
+ tasks. In this example, we use it to draw on a \c DisplayWidget instance
+ and on a QSvgGenerator object. We show how the painting is performed to
+ demonstrate that there is nothing device-specific about the process:
+
+ \snippet examples/painting/svggenerator/displaywidget.cpp paint function
+
+ \section1 The Window Class
+
+ The \c Window class represents the example's window, containing the user
+ interface, which has been created using Qt Designer:
+
+ \snippet examples/painting/svggenerator/window.h Window class definition
+
+ As with the \c DisplayWidget class, we concentrate on the parts of the code
+ which are concerned with painting and SVG generation. In the \c Window
+ class, the \c saveSvg() function is called whenever the \gui{Save As...}
+ button is clicked; this connection was defined in the \c{window.ui} file
+ using Qt Designer.
+
+ The start of the \c saveSvg() function performs the task of showing a file
+ dialog so that the user can specify a SVG file to save the drawing to.
+
+ \snippet examples/painting/svggenerator/window.cpp save SVG
+
+ In the rest of the function, we set up the generator and configure it to
+ generate output with the appropriate dimensions and write to the
+ user-specified file. We paint on the QSvgGenerator object in the same way
+ that we paint on a widget, calling the \c DisplayWidget::paint() function
+ so that we use exactly the same code that we used to display the drawing.
+
+ The generation process itself begins with the call to the painter's
+ \l{QPainter::}{begin()} function and ends with call to its
+ \l{QPainter::}{end()} function. The QSvgGenerator paint device relies on
+ the explicit use of these functions to ensure that output is written to
+ the file.
+
+ \section1 Further Reading
+
+ The \l{SVG Viewer Example} shows how to display SVG drawings in an
+ application, and can be used to show the contents of SVG files created
+ by this example.
+
+ See the QtSvg module documentation for more information about SVG and Qt's
+ SVG classes.
+*/