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author | Nico Vertriest <nico.vertriest@digia.com> | 2014-01-23 16:10:26 +0100 |
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committer | The Qt Project <gerrit-noreply@qt-project.org> | 2014-01-31 16:18:07 +0100 |
commit | 0b26ad05bbadeef493317c994cc7ccb53b0a612c (patch) | |
tree | c6d790f47b7a6887fd3341bdda331e02f6a03d99 /examples/widgets/gestures/imagegestures/doc | |
parent | 14addd2cbbb013a256a2c59d9a5b3ac8ca951e0d (diff) |
Doc: corrected link/example errors
Update pro files after move gestures folder
Update snippet statements
Corrected path in imagegestures.pro
Task-number: QTBUG-34749
Change-Id: Icc19908914e36507e412ab63bf0cc2809aa48e17
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Diffstat (limited to 'examples/widgets/gestures/imagegestures/doc')
-rw-r--r-- | examples/widgets/gestures/imagegestures/doc/src/imagegestures.qdoc | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/examples/widgets/gestures/imagegestures/doc/src/imagegestures.qdoc b/examples/widgets/gestures/imagegestures/doc/src/imagegestures.qdoc new file mode 100644 index 0000000000..d6d215d6bd --- /dev/null +++ b/examples/widgets/gestures/imagegestures/doc/src/imagegestures.qdoc @@ -0,0 +1,100 @@ +/**************************************************************************** +** +** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/legal +** +** 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 Digia. For licensing terms and +** conditions see http://qt.digia.com/licensing. For further information +** use the contact form at http://qt.digia.com/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: http://www.gnu.org/copyleft/fdl.html. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/*! + \example gestures/imagegestures + \title Image Gestures Example + + This example shows how to enable gestures for a widget and use gesture input + to perform actions. + + We use two classes to create the user interface for the application: \c MainWidget + and \c ImageWidget. The \c MainWidget class is simply used as a container for the + \c ImageWidget class, which we will configure to accept gesture input. Since we + are interested in the way gestures are used, we will concentrate on the + implementation of the \c ImageWidget class. + + \section1 ImageWidget Class Definition + + The \c ImageWidget class is a simple QWidget subclass that reimplements the general + QWidget::event() handler function in addition to several more specific event handlers: + + \snippet gestures/imagegestures/imagewidget.h class definition begin + \dots + \snippet gestures/imagegestures/imagewidget.h class definition end + + We also implement a private helper function, \c gestureEvent(), to help manage + gesture events delivered to the widget, and three functions to perform actions + based on gestures: \c panTriggered(), \c pinchTriggered() and \c swipeTriggered(). + + \section1 ImageWidget Class Implementation + + In the widget's constructor, we begin by setting up various parameters that will + be used to control the way images are displayed. + + \snippet gestures/imagegestures/imagewidget.cpp constructor + + We enable three of the standard gestures for the widget by calling QWidget::grabGesture() + with the types of gesture we need. These will be recognized by the application's + default gesture recognizer, and events will be delivered to our widget. + + Since QWidget does not define a specific event handler for gestures, the widget + needs to reimplement the general QWidget::event() to receive gesture events. + + \snippet gestures/imagegestures/imagewidget.cpp event handler + + We implement the event handler to delegate gesture events to a private function + specifically written for the task, and pass all other events to QWidget's + implementation. + + The \c gestureHandler() function examines the gestures supplied by the + newly-delivered QGestureEvent. Since only one gesture of a given type can be + used on a widget at any particular time, we can check for each gesture type + using the QGestureEvent::gesture() function: + + \snippet gestures/imagegestures/imagewidget.cpp gesture event handler + + If a QGesture object is supplied for a certain type of gesture, we call a special + purpose function to deal with it, casting the gesture object to the appropriate + QGesture subclass. + + To illustrate how a standard gesture can be interpreted by an application, we + show the implementation of the \c swipeTriggered() function, which handles the + gesture associated with a brushing or swiping motion on the user's display or + input device: + + \snippet gestures/imagegestures/imagewidget.cpp swipe function + + The QSwipeGesture class provides specialized functions and defines a enum + to make it more convenient for developers to discover which direction, if + any, the user swiped the display. Here, we simply navigate to the previous + image in the collection if the user swiped upwards or to the left; otherwise + we navigate to the next image in the collection. + + The other gestures are also handled by special purpose functions, but use + the values of properties held by the QGesture object passed to them. +*/ |