The gdk-pixbuf library provides a simple mechanism to load and represent animations.
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Inherits Glib::Object.
The gdk-pixbuf library provides a simple mechanism to load and represent animations.
An animation is conceptually a series of frames to be displayed over time. Each frame is the same size. The animation may not be represented as a series of frames internally; for example, it may be stored as a sprite and instructions for moving the sprite around a background. To display an animation you don't need to understand its representation, however; you just ask gdk-pixbuf what should be displayed at a given point in time.
| G_GNUC_BEGIN_IGNORE_DEPRECATIONS Glib::RefPtr< PixbufAnimationIter > Gdk::PixbufAnimation::get_iter |
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const GTimeVal * |
start_time | ) |
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Get an iterator for displaying an animation.
The iterator provides the frames that should be displayed at a given time. It should be freed after use with Glib::object_unref().
start_time would normally come from Glib::get_current_time(), and marks the beginning of animation playback. After creating an iterator, you should immediately display the pixbuf returned by Gdk::PixbufAnimationIter::get_pixbuf(). Then, you should install a timeout (with Glib::timeout_add()) or by some other mechanism ensure that you'll update the image after Gdk::PixbufAnimationIter::get_delay_time() milliseconds. Each time the image is updated, you should reinstall the timeout with the new, possibly-changed delay time.
As a shortcut, if start_time is nullptr, the result of Glib::get_current_time() will be used automatically.
To update the image (i.e. possibly change the result of Gdk::PixbufAnimationIter::get_pixbuf() to a new frame of the animation), call Gdk::PixbufAnimationIter::advance().
If you're using Gdk::PixbufLoader, in addition to updating the image after the delay time, you should also update it whenever you receive the area_updated signal and Gdk::PixbufAnimationIter::on_currently_loading_frame() returns true. In this case, the frame currently being fed into the loader has received new data, so needs to be refreshed. The delay time for a frame may also be modified after an area_updated signal, for example if the delay time for a frame is encoded in the data after the frame itself. So your timeout should be reinstalled after any area_updated signal.
A delay time of -1 is possible, indicating "infinite."
- Parameters
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| start_time | Time when the animation starts playing. |
- Returns
- An iterator to move over the animation.
| Glib::RefPtr< Pixbuf > Gdk::PixbufAnimation::get_static_image |
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| ) |
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If an animation is really just a plain image (has only one frame), this function returns that image.
If the animation is an animation, this function returns a reasonable thing to display as a static unanimated image, which might be the first frame, or something more sophisticated. If an animation hasn't loaded any frames yet, this function will return nullptr.
- Returns
- Unanimated image representing the animation.
