806dda08d6
Updated those .qdoc files to refer to the new relative examples emplacement. Images and snippets to be moved later. Also grouped all widgets related examples under widgets. Change-Id: Ib29696e2d8948524537f53e8dda88f9ee26a597f Reviewed-by: J-P Nurmi <j-p.nurmi@nokia.com>
83 lines
3.0 KiB
Plaintext
83 lines
3.0 KiB
Plaintext
/****************************************************************************
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**
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** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
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** Contact: http://www.qt-project.org/
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**
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** This file is part of the documentation of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:FDL$
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** GNU Free Documentation License
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** Alternatively, this file may be used under the terms of the GNU Free
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** Documentation License version 1.3 as published by the Free Software
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** Foundation and appearing in the file included in the packaging of
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** this file.
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**
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** Other Usage
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** Alternatively, this file may be used in accordance with the terms
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** and conditions contained in a signed written agreement between you
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** and Nokia.
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**
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**
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**
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**
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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/*!
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\example itemviews/chart
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\title Chart Example
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The Chart example shows how to create a custom view for the model/view framework.
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\image chart-example.png
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In this example, the items in a table model are represented as slices in a pie chart,
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relying on the flexibility of the model/view architecture to handle custom editing
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and selection features.
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\b{Note that you only need to create a new view class if your data requires a
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specialized representation.} You should first consider using a standard QListView,
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QTableView, or QTreeView with a custom QItemDelegate subclass if you need to
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represent data in a special way.
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\omit
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\section1 PieView Class Definition
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The \c PieView class is a subclass of QAbstractItemView. The base class provides
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much of the functionality required by view classes, so we only need to provide
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implementations for three public functions: visualRect(), scrollTo(), and
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indexAt(). However, the view needs to maintain strict control over its look and
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feel, so we also provide implementations for a number of other functions:
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\snippet itemviews/chart/pieview.h 0
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\section1 PieView Class Implementation
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The paint event renders the data from the standard item model as a pie chart.
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We interpret the data in the following way:
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\list
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\li Column 0 contains data in two different roles:
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The \l{Qt::ItemDataRole}{DisplayRole} contains a label, and the
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\l{Qt::ItemDataRole}{DecorationRole} contains the color of the pie slice.
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\li Column 1 contains a quantity which we will convert to the angular extent of
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the slice.
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\endlist
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The figure is always drawn with the chart on the left and the key on
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the right. This means that we must try and obtain an area that is wider
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than it is tall. We do this by imposing a particular aspect ratio on
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the chart and applying it to the available vertical space. This ensures
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that we always obtain the maximum horizontal space for the aspect ratio
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used.
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We also apply fixed size margin around the figure.
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We use logical coordinates to draw the chart and key, and position them
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on the view using viewports.
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\endomit
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*/
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