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diff --git a/doc/src/examples/chart.qdoc b/doc/src/examples/chart.qdoc new file mode 100644 index 0000000..22f8a51 --- /dev/null +++ b/doc/src/examples/chart.qdoc @@ -0,0 +1,96 @@ +/**************************************************************************** +** +** 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 itemviews/chart + \title Chart Example + + The Chart example shows how to create a custom view for the model/view framework. + + \image chart-example.png + + In this example, the items in a table model are represented as slices in a pie chart, + relying on the flexibility of the model/view architecture to handle custom editing + and selection features. + + \bold{Note that you only need to create a new view class if your data requires a + specialized representation.} You should first consider using a standard QListView, + QTableView, or QTreeView with a custom QItemDelegate subclass if you need to + represent data in a special way. + + \omit + \section1 PieView Class Definition + + The \c PieView class is a subclass of QAbstractItemView. The base class provides + much of the functionality required by view classes, so we only need to provide + implementations for three public functions: visualRect(), scrollTo(), and + indexAt(). However, the view needs to maintain strict control over its look and + feel, so we also provide implementations for a number of other functions: + + \snippet examples/itemviews/chart/pieview.h 0 + + + + \section1 PieView Class Implementation + + The paint event renders the data from the standard item model as a pie chart. + We interpret the data in the following way: + + \list + \o Column 0 contains data in two different roles: + The \l{Qt::ItemDataRole}{DisplayRole} contains a label, and the + \l{Qt::ItemDataRole}{DecorationRole} contains the color of the pie slice. + \o Column 1 contains a quantity which we will convert to the angular extent of + the slice. + \endlist + + The figure is always drawn with the chart on the left and the key on + the right. This means that we must try and obtain an area that is wider + than it is tall. We do this by imposing a particular aspect ratio on + the chart and applying it to the available vertical space. This ensures + that we always obtain the maximum horizontal space for the aspect ratio + used. + We also apply fixed size margin around the figure. + + We use logical coordinates to draw the chart and key, and position them + on the view using viewports. + \endomit +*/ |