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diff --git a/doc/src/plugins/qml-multimedia.qdoc b/doc/src/plugins/qml-multimedia.qdoc new file mode 100644 index 000000000..facae3c92 --- /dev/null +++ b/doc/src/plugins/qml-multimedia.qdoc @@ -0,0 +1,291 @@ +/**************************************************************************** +** +** Copyright (C) 2010 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. +** +** $QT_BEGIN_LICENSE:FDL$ +** 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 Technology Preview License Agreement accompanying +** this package. +** +** 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. +** +** If you have questions regarding the use of this file, please contact +** Nokia at qt-info@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/*! + \group qml-multimedia + \title QML Multimedia Plugin + QML Support for the QtMobility Project Multimedia API. +*/ + +/*! + \page qml-multimedia.html + + \title Multimedia QML Plugin + + \brief A QML plugin for the QtMobility Project Multimedia API. + + + \section1 Overview + + The Multimedia API in the QtMobility Project gives developers a simplified way to use audio and video playback, and access camera functionality. The Multimedia QML Plugin provides a QML friendly interface to these features. + + \section1 Elements + + \section2 Audio + + The \l Audio element is an easy way to add audio playback to a Qt Quick + scene. QtMobility provides properties for control, methods (functions) and signals. + + The code extract below shows the creation and use of an audio element. + + \qml + + import Qt 4.7 + import QtMultimediaKit 1.1 + // ... + + Audio { + id: playMusic + source: "music.wav" + } + + MouseArea { + id: playArea + anchors.fill: parent + onPressed: { playMusic.play() } + } + + \endqml + + The snippet above shows how the inclusion of \i playMusic enables audio features on the element that contains it. So that when the parent's MouseArea is clicked the \l {Audio::play()}{play()} method of the audio element is run. Other typical audio control methods are available such as \l {Audio::pause}{pause()} and \l {Audio::stop()}{stop()}. + + Much of the getting / setting of \l Audio parameters is done through properties. These include + \table 70% + \header + \o Property + \o Description + \row + \o \l {Audio::source}{source} + \o The source URL of the media. + \row + \o \l {Audio::autoLoad}{autoLoad} + \o Indicates if loading of media should begin immediately. + \row + \o \l{Audio::playing}{playing} + \o Indicates that the media is playing. + \row + \o \l {Audio::paused}{paused} + \o The media is paused. + \row + \o \l{Audio::status}{status} + \o The status of media loading. + \row + \o \l{Audio::duration}{duration} + \o Amount of time in milliseconds the media will play. + \row + \o \l{Audio::position}{position} + \o Current position in the media in milliseconds of play. + \row + \o \l{Audio::volume}{volume} + \o Audio output volume: from 0.0 (silent) to 1.0 (maximum) + \row + \o \l{Audio::muted}{muted} + \o Indicates audio is muted. + \row + \o \l{Audio::bufferProgress}{bufferProgress} + \o Indicates how full the data buffer is: 0.0 (empty) to 1.0 (full). + \row + \o \l{Audio::seekable}{seekable} + \o Indicates whether the audio position can be changed. + \row + \o \l{Audio::playbackRate}{playbackRate} + \o The rate at which audio is played at as a multiple of the normal rate. + \row + \o \l{Audio::error}{error} + \o An error code for the error state including NoError + \row + \o \l{Audio::errorString}{errorString} + \o A description of the current error condition. + \endtable + + The set of signals available allow the developer to create custom behavior when the following events occur, + + \table 70% + \header + \o Signal + \o Description + \row + \o \l{Audio::onStarted}{onStarted} + \o Called when playback has been started. + \row + \o \l{Audio::onResumed}{onResumed} + \o Called when playback is resumed from the paused state. + \row + \o \l{Audio::onPaused}{onPaused} + \o Called when playback is paused. + \row + \o \l{Audio::onStopped}{onStopped} + \o Called when playback is stopped. + \row + \o \l{Audio::onError}{onError} + \o Called when the specified error occurs. + \endtable + + \section2 Camera + + The \l Camera element in the plugin enables still image capture using + QML. The element has methods for starting and stopping the camera, capturing + the image, camera settings and many signals indicating critical events. + + The follow code is taken from the \l {QML Camera Example}. This snippet + shows the setting up of the \l Camera element + + \qml + + Camera { + id: camera + x : 0 + y : 0 + width : 640 + height : 480 + focus : visible //to receive focus and capture key events + //captureResolution : "640x480" + + flashMode: stillControls.flashMode + whiteBalanceMode: stillControls.whiteBalance + exposureCompensation: stillControls.exposureCompensation + + onImageCaptured : { + photoPreview.source = preview + stillControls.previewAvailable = true + cameraUI.state = "PhotoPreview" + } + } + + \endqml + + Notice that the slot for the \l {Camera::imageCaptured()}{imageCaptured()} + signal is implemented in \i onImageCaptured. However, this code only + changes some state information to allow previewing. + + The capture call itself is part of the implementation of the button + that the user presses to take the image. It uses a call to + \l {Camera::captureImage()}{captureImage()}: + + \qml + + CameraButton { + text: "Capture" + onClicked: camera.captureImage() + } + + \endqml + + + \section2 Video + + Adding video playback, with sound, to a Qt Quick scene is also easy. The process is very similar to that of Audio above, in fact \l {Video} shares many of the property names, methods and signals. Here is the equivalent sample code to implement a video playback element in a scene + + \qml + + Video { + id: video + width : 800 + height : 600 + source: "video.avi" + + MouseArea { + anchors.fill: parent + onClicked: { + video.play() + } + } + + focus: true + Keys.onSpacePressed: video.paused = !video.paused + Keys.onLeftPressed: video.position -= 5000 + Keys.onRightPressed: video.position += 5000 + } + + \endqml + + There are similar features like \l {Video::play()}{play()} with new + features specific to video. + + In the above sample when the parent of MouseArea is clicked, an area of 800x600 pixels with an id of 'video', the source "video.avi" will play in that area. Notice also that signals for the Keys element have been defined so that a spacebar will toggle the pause button; the left arrow will move the current position in the video to 5 seconds previously; and the right arrow will advance the current position in the video by 5 seconds. + + Most of the differences will obviously be about video control and information. There are many properties associated with the \l {Video} element, most of them deal with meta-data, control of the video media and aspects of presentation. + + \section2 SoundEffect + + The \l SoundEffect element provides a way to play short sound effects, like in video games. Multiple sound effect instances can be played simultaneously. + You should use the \l Audio element for music playback. + + \qml + + import Qt 4.7 + import QtMultimediaKit 1.1 + + + SoundEffect { + id: effect + source: "test.wav" + } + MouseArea { + id: playArea + anchors.fill: parent + onPressed: { effect.play() } + } + + \endqml + + + In the above sample the sound effect will be played when the MouseArea is clicked. + + For a complete description of this element, see \l SoundEffect + + \section2 Camera + + Adding access to the camera viewfinder, and capturing images is possible by using the \l Camera element. You can adjust capture settings + including white balance, exposure compensation and flash mode, and control zoom. + + \qml + import Qt 4.7 + import QtMultimediaKit 1.1 + + Camera { + focus : visible // to receive focus and capture key events when visible + + flashMode: Camera.FlashRedEyeReduction + whiteBalanceMode: Camera.WhiteBalanceFlash + exposureCompensation: -1.0 + + onImageCaptured : { + photoPreview.source = preview // Show the preview in an Image element + } + + } + \endqml + + For a complete description of this element, see \l Camera, and look at the \l {declarative-camera}{QML Camera Example}. + + \section1 Multimedia QML Elements + + \annotatedlist qml-multimedia +*/ + + |