The QMovie class is a convenience class for playing movies with QImageReader . 更多...
| 头： | #include <QMovie> |
| qmake: | QT += gui |
| 继承： | QObject |
| enum | CacheMode { CacheNone, CacheAll } |
| enum | MovieState { NotRunning, Paused, Running } |
| QMovie (QObject * parent = nullptr) | |
| QMovie (QIODevice * device , const QByteArray & format = QByteArray(), QObject * parent = nullptr) | |
| QMovie (const QString & fileName , const QByteArray & format = QByteArray(), QObject * parent = nullptr) | |
| virtual | ~QMovie () |
| QColor | backgroundColor () const |
| QMovie::CacheMode | cacheMode () const |
| int | currentFrameNumber () const |
| QImage | currentImage () const |
| QPixmap | currentPixmap () const |
| QIODevice * | device () const |
| QString | fileName () const |
| QByteArray | format () const |
| int | frameCount () const |
| QRect | frameRect () const |
| bool | isValid () const |
| bool | jumpToFrame (int frameNumber ) |
| QImageReader::ImageReaderError | lastError () const |
| QString | lastErrorString () const |
| int | loopCount () const |
| int | nextFrameDelay () const |
| QSize | scaledSize () |
| void | setBackgroundColor (const QColor & color ) |
| void | setCacheMode (QMovie::CacheMode mode ) |
| void | setDevice (QIODevice * device ) |
| void | setFileName (const QString & fileName ) |
| void | setFormat (const QByteArray & format ) |
| void | setScaledSize (const QSize & size ) |
| int | speed () const |
| QMovie::MovieState | state () const |
| bool | jumpToNextFrame () |
| void | setPaused (bool paused ) |
| void | setSpeed (int percentSpeed ) |
| void | start () |
| void | stop () |
| void | error (QImageReader::ImageReaderError error ) |
| void | finished () |
| void | frameChanged (int frameNumber ) |
| void | resized (const QSize & size ) |
| void | started () |
| void | stateChanged (QMovie::MovieState state ) |
| void | updated (const QRect & rect ) |
| const QMetaObject | staticMetaObject |
| QList<QByteArray> | supportedFormats () |
The QMovie class is a convenience class for playing movies with QImageReader .
This class is used to show simple animations without sound. If you want to display video and media content, use the Qt Multimedia multimedia framework instead.
First, create a QMovie object by passing either the name of a file or a pointer to a QIODevice containing an animated image format to QMovie 's constructor. You can call isValid () to check if the image data is valid, before starting the movie. To start the movie, call start (). QMovie 将进入 运行 state, and emit started () 和 stateChanged (). To get the current state of the movie, call state ().
To display the movie in your application, you can pass your QMovie 对象到 QLabel::setMovie ()。范例：
QLabel label; QMovie *movie = new QMovie("animations/fire.gif"); label.setMovie(movie); movie->start();
Whenever a new frame is available in the movie, QMovie 将发射 updated (). If the size of the frame changes, resized () is emitted. You can call currentImage () 或 currentPixmap () to get a copy of the current frame. When the movie is done, QMovie 发射 finished (). If any error occurs during playback (i.e, the image file is corrupt), QMovie 将发射 error ().
You can control the speed of the movie playback by calling setSpeed (), which takes the percentage of the original speed as an argument. Pause the movie by calling setPaused (true)。 QMovie will then enter Paused state and emit stateChanged (). If you call setPaused (false), QMovie will reenter 运行 state and start the movie again. To stop the movie, call stop ().
Certain animation formats allow you to set the background color. You can call setBackgroundColor () to set the color, or backgroundColor () to retrieve the current background color.
currentFrameNumber () returns the sequence number of the current frame. The first frame in the animation has the sequence number 0. frameCount () returns the total number of frames in the animation, if the image format supports this. You can call loopCount () to get the number of times the movie should loop before finishing. nextFrameDelay () returns the number of milliseconds the current frame should be displayed.
QMovie can be instructed to cache frames of an animation by calling setCacheMode ().
调用 supportedFormats () for a list of formats that QMovie 支持。
另请参阅 QLabel , QImageReader ，和 影片范例 .
此枚举描述不同缓存模式，为 QMovie .
| 常量 | 值 | 描述 |
|---|---|---|
QMovie::CacheNone
|
0
|
没有帧被缓存 (默认)。 |
QMovie::CacheAll
|
1
|
所有帧都被缓存。 |
此枚举描述不同状态为 QMovie .
| 常量 | 值 | 描述 |
|---|---|---|
QMovie::NotRunning
|
0
|
The movie is not running. This is QMovie 's initial state, and the state it enters after stop () has been called or the movie is finished. |
QMovie::Paused
|
1
|
The movie is paused, and QMovie stops emitting updated () 或 resized (). This state is entered after calling pause() or setPaused (true). The current frame number it kept, and the movie will continue with the next frame when unpause() or setPaused (false) 被调用。 |
QMovie::Running
|
2
|
The movie is running. |
此特性保持影片的缓存模式
Caching frames can be useful when the underlying animation format handler that QMovie relies on to decode the animation data does not support jumping to particular frames in the animation, or even "rewinding" the animation to the beginning (for looping). Furthermore, if the image data comes from a sequential device, it is not possible for the underlying animation handler to seek back to frames whose data has already been read (making looping altogether impossible).
To aid in such situations, a QMovie object can be instructed to cache the frames, at the added memory cost of keeping the frames in memory for the lifetime of the object.
默认情况下，此特性被设为 CacheNone .
访问函数：
| QMovie::CacheMode | cacheMode () const |
| void | setCacheMode (QMovie::CacheMode mode ) |
另请参阅 QMovie::CacheMode .
此特性保持影片的速度
The speed is measured in percentage of the original movie speed. The default speed is 100%. Example:
QMovie movie("racecar.gif"); movie.setSpeed(200); // 2x speed
访问函数：
| int | speed () const |
| void | setSpeed (int percentSpeed ) |
构造 QMovie object, passing the parent 对象到 QObject 的构造函数。
另请参阅 setFileName (), setDevice ()，和 setFormat ().
构造 QMovie 对象。 QMovie will use read image data from device , which it assumes is open and readable. If format is not empty, QMovie will use the image format format for decoding the image data. Otherwise, QMovie will attempt to guess the format.
The parent 对象被传递给 QObject 的构造函数。
构造 QMovie 对象。 QMovie will use read image data from fileName 。若 format is not empty, QMovie will use the image format format for decoding the image data. Otherwise, QMovie will attempt to guess the format.
The parent 对象被传递给 QObject 的构造函数。
[虚拟]
QMovie::
~QMovie
()
销毁 QMovie 对象。
Returns the background color of the movie. If no background color has been assigned, an invalid QColor 被返回。
另请参阅 setBackgroundColor ().
Returns the sequence number of the current frame. The number of the first frame in the movie is 0.
返回当前帧，作为 QImage .
另请参阅 currentPixmap () 和 updated ().
返回当前帧，作为 QPixmap .
另请参阅 currentImage () 和 updated ().
Returns the device QMovie reads image data from. If no device has currently been assigned, 0 is returned.
另请参阅 setDevice () 和 fileName ().
[signal]
void
QMovie::
error
(
QImageReader::ImageReaderError
error
)
此信号被发射由 QMovie when the error error occurred during playback. QMovie will stop the movie, and enter QMovie::NotRunning 状态。
另请参阅 lastError () 和 lastErrorString ().
Returns the name of the file that QMovie reads image data from. If no file name has been assigned, or if the assigned device is not a file, an empty QString 被返回。
另请参阅 setFileName () 和 device ().
[signal]
void
QMovie::
finished
()
This signal is emitted when the movie has finished.
另请参阅 QMovie::stop ().
Returns the format that QMovie uses when decoding image data. If no format has been assigned, an empty QByteArray() is returned.
另请参阅 setFormat ().
[signal]
void
QMovie::
frameChanged
(
int
frameNumber
)
This signal is emitted when the frame number has changed to frameNumber 。可以调用 currentImage () 或 currentPixmap () to get a copy of the frame.
该函数在 Qt 4.1 引入。
Returns the number of frames in the movie.
Certain animation formats do not support this feature, in which case 0 is returned.
Returns the rect of the last frame. If no frame has yet been updated, an invalid QRect 被返回。
另请参阅 currentImage () 和 currentPixmap ().
返回
true
if the movie is valid (e.g., the image data is readable and the image format is supported); otherwise returns
false
.
For information about why the movie is not valid, see lastError ().
Jumps to frame number
frameNumber
。返回
true
当成功时；否则返回
false
.
[slot]
bool
QMovie::
jumpToNextFrame
()
Jumps to the next frame. Returns
true
当成功时；否则返回
false
.
Returns the most recent error that occurred while attempting to read image data.
另请参阅 lastErrorString ().
Returns a human-readable representation of the most recent error that occurred while attempting to read image data.
另请参阅 lastError ().
Returns the number of times the movie will loop before it finishes. If the movie will only play once (no looping), loopCount returns 0. If the movie loops forever, loopCount returns -1.
Note that, if the image data comes from a sequential device (e.g. a socket), QMovie can only loop the movie if the cacheMode 被设为 QMovie::CacheAll .
Returns the number of milliseconds QMovie will wait before updating the next frame in the animation.
[signal]
void
QMovie::
resized
(const
QSize
&
size
)
This signal is emitted when the current frame has been resized to size . This effect is sometimes used in animations as an alternative to replacing the frame. You can call currentImage () 或 currentPixmap () to get a copy of the updated frame.
Returns the scaled size of frames.
该函数在 Qt 4.1 引入。
另请参阅 setScaledSize () 和 QImageReader::scaledSize ().
For image formats that support it, this function sets the background color to color .
另请参阅 backgroundColor ().
把当前设备设为 device . QMovie will read image data from this device when the movie is running.
另请参阅 device () 和 setFormat ().
Sets the name of the file that QMovie reads image data from, to fileName .
另请参阅 fileName (), setDevice ()，和 setFormat ().
Sets the format that QMovie will use when decoding image data, to format 。默认情况下， QMovie will attempt to guess the format of the image data.
可以调用 supportedFormats () 了解完整格式列表 QMovie 支持。
另请参阅 format () 和 QImageReader::supportedImageFormats ().
[slot]
void
QMovie::
setPaused
(
bool
paused
)
若 paused 为 True， QMovie 将进入 Paused state and emit stateChanged (Paused); otherwise it will enter 运行 state and emit stateChanged (Running).
另请参阅 state ().
Sets the scaled frame size to size .
该函数在 Qt 4.1 引入。
另请参阅 scaledSize () 和 QImageReader::setScaledSize ().
[slot]
void
QMovie::
start
()
Starts the movie. QMovie 将进入 运行 state, and start emitting updated () 和 resized () as the movie progresses.
若 QMovie is in the Paused state, this function is equivalent to calling setPaused (false). If QMovie is already in the 运行 state, this function does nothing.
[signal]
void
QMovie::
started
()
此信号发射后于 QMovie::start () has been called, and QMovie has entered QMovie::Running 状态。
返回当前状态，为 QMovie .
另请参阅 MovieState and stateChanged ().
[signal]
void
QMovie::
stateChanged
(
QMovie::MovieState
state
)
This signal is emitted every time the state of the movie changes. The new state is specified by state .
另请参阅 QMovie::state ().
[slot]
void
QMovie::
stop
()
停止影片。 QMovie 进入 NotRunning state, and stops emitting updated () 和 resized ()。若 start () is called again, the movie will restart from the beginning.
若 QMovie is already in the NotRunning state, this function does nothing.
[static]
QList
<
QByteArray
> QMovie::
supportedFormats
()
返回图像格式列表支持通过 QMovie .
该函数在 Qt 4.1 引入。
另请参阅 QImageReader::supportedImageFormats ().
[signal]
void
QMovie::
updated
(const
QRect
&
rect
)
This signal is emitted when the rect rect in the current frame has been updated. You can call currentImage () 或 currentPixmap () to get a copy of the updated frame.