/**************************************************************************** ** ** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies). ** All rights reserved. ** Contact: Nokia Corporation (qt-info@nokia.com) ** ** This file is part of the documentation of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:FDL$ ** GNU Free Documentation License ** 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. ** ** Other Usage ** Alternatively, this file may be used in accordance with the terms ** and conditions contained in a signed written agreement between you ** and Nokia. ** ** ** ** ** $QT_END_LICENSE$ ** ****************************************************************************/ /*! \example widgets/symbianvibration \group all-examples \title Symbian Vibration Example \brief The Symbian Vibrator example shows how to get fine-grained vibration control on Symbian devices. Native Symbian APIs have to be used to enable vibration, since QtMobility doesn't provide an interface for it yet. It is, however, planned to be included in a future release. In anticipation for that, we make use of the \c XQVibra class that was a part of the Mobile Extensions Technology Preview API for Qt for Symbian. The pre-compiled libraries are no longer compatible with Qt 4.6, but we can include the source code itself with the project. \image symbianvibration-example.png Screenshot of the Symbian Vibration example The example application divides the window into rectangles, which can be pressed to make the device vibrate. Pressing different rectangles make the device vibrate with different intensities. Each rectangle has a different color and its intensity number is drawn on top of it. Moving the cursor from one rectangle to another changes the vibration intensity to that of the new one. Vibration stops when the mouse button has been released. It is also possible to launch a short burst of vibration through the menu. The example consists of four classes: \list \o \c XQVibra is the vibration interface class taken from the Mobile Extensions for Qt for Symbian. \o \c XQVibraPrivate is the Symbian specific private implementation of the vibration implementation. \o \c VibrationSurface is a custom widget that uses a XQVibra instance to vibrate the device depending on where the user presses. \o \c MainWindow inherits from QMainWindow and contains a \c VibrationSurface as its central widget, and also has a menu from which it is possible to make the phone vibrate. \endlist \section1 XQVibra Class Definition The \c XQVibra class uses the pimpl-idiom to hide the platform specific implementation behind a common interface. Technically it would be possible to support more target platforms, with only the addition of a private implementation. The rest of the code would work the same, since only the common interface is used. \snippet examples/widgets/symbianvibration/xqvibra.h 0 \c XQVibra provides a very simple interface for us to use. The interesting part are the three slots \c start(), \c stop() and \c setIntensity(). Calling the start method initiates vibration for the specified duration. Calling it while the device is already vibrating causes it to stop the current one and start the new one, even if the intensities are the same. The \c setIntensity() method should be called before starting vibration. \section1 VibrationSurface Class Definition \c VibrationSurface inherits from QWidget and acts like a controller for a \c XQVibra object. It responds to mouse events and performs custom painting. \snippet examples/widgets/symbianvibration/vibrationsurface.h 0 The virtual event methods are reimplemented from QWidget. As can be seen, there is no public programmable interface beyond what QWidget provides. \section1 VibrationSurface Class Implementation Mouse events control the intensity of the vibration. \snippet examples/widgets/symbianvibration/vibrationsurface.cpp 0 \codeline \snippet examples/widgets/symbianvibration/vibrationsurface.cpp 1 \codeline \snippet examples/widgets/symbianvibration/vibrationsurface.cpp 2 Presses starts the vibration, movement changes the intensity and releases stops the vibration. To set the right amount of vibration, the private method \c applyIntensity() is used. It sets the vibration intensity according to which rectangle the mouse currently resides in. \snippet examples/widgets/symbianvibration/vibrationsurface.cpp 3 We make sure only to change the intensity if it is different than last time, so that the vibrator isn't stopped and restarted unnecessarily. The range of vibration intensity ranges from 0 to XQVibra::MaxIntensity. We divide this range into a set of levels. The number of levels and the intensity increase for each level are stored in two constants. \snippet examples/widgets/symbianvibration/vibrationsurface.cpp 4 Each rectangle has an intensity of one \c IntensityPerLevel more than the previous one. \snippet examples/widgets/symbianvibration/vibrationsurface.cpp 5 The rectangles are either put in a row, if the widget's width is greater than its height (landscape), otherwise they are put in a column (portrait). Each rectangle's size is thus dependent on the length of the width or the height of the widget, whichever is longer. The length is then divided by the number of levels, which gets us either the height or the width of each rectangle. The dx and dy specify the distance from one rectangle to the next, which is the same as either the width or height of the rectangle. \snippet examples/widgets/symbianvibration/vibrationsurface.cpp 6 For each level of intensity, we draw a rectangle with increasing brightness. On top of the rectangle a text label is drawn, specifying the intesity of this level. We use the rectangle rect as a template for drawing, and move it down or right at each iteration. The intensity is calculated by dividing the greater of the width and height into \c NumberOfLevels slices. \snippet examples/widgets/symbianvibration/vibrationsurface.cpp 7 In case the widget's geometry is too small to fit all the levels, the user interface will not work. For simplicity, we just return 0. When we know the axis along which the rectangles lie, we can find the one in which the mouse cursor lie. \snippet examples/widgets/symbianvibration/vibrationsurface.cpp 8 The final clamp of the intensity value at the end is necessary in case the mouse coordinate lies outside the widget's geometry. \section1 MainWindow Class Definition Here's the definition of the \c MainWindow class: \snippet examples/widgets/symbianvibration/mainwindow.h 0 \c MainWindow is a top level window that uses a \c XQVibra and a \c VibrationSurface. It also adds a menu option to the menu bar which can start a short vibration. \section1 MainWindow Class Implementation In the \c MainWindow constructor the \c XQVibra and the \c VibrationSurface are created. An action is added to the menu and is connected to the vibrate slot. \snippet examples/widgets/symbianvibration/mainwindow.cpp 0 The \c vibrate() slot offers a way to invoke the vibration in case no mouse is present on the device. \snippet examples/widgets/symbianvibration/mainwindow.cpp 1 \section1 Symbian Vibration Library The \c XQVibra class requires a platform library to be included. It is included in the \c .pro file for the symbian target. \quotefromfile examples/widgets/symbianvibration/symbianvibration.pro \skipto /^symbian \{/ \printuntil /^\}/ */