Top |
Functions
Object Hierarchy
GObject ├── GdkPixbufAnimation │ ╰── GdkPixbufSimpleAnim ╰── GdkPixbufAnimationIter
Description
The GdkPixBuf library provides a simple mechanism to load and represent animations. An animation is conceptually a series of frames to be displayed over time. 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 GdkPixBuf what should be displayed at a given point in time.
Functions
gdk_pixbuf_animation_new_from_file ()
GdkPixbufAnimation * gdk_pixbuf_animation_new_from_file (const char *filename
,GError **error
);
Creates a new animation by loading it from a file. The file format is detected automatically. If the file's format does not support multi-frame images, then an animation with a single frame will be created. Possible errors are in the GDK_PIXBUF_ERROR and G_FILE_ERROR domains.
gdk_pixbuf_animation_new_from_resource ()
GdkPixbufAnimation * gdk_pixbuf_animation_new_from_resource (const char *resource_path
,GError **error
);
Creates a new pixbuf animation by loading an image from an resource.
The file format is detected automatically. If NULL
is returned, then
error
will be set.
Returns
A newly-created animation, or NULL
if any of several error
conditions occurred: the file could not be opened, the image format is
not supported, there was not enough memory to allocate the image buffer,
the stream contained invalid data, or the operation was cancelled.
Since: 2.28
gdk_pixbuf_animation_new_from_stream ()
GdkPixbufAnimation * gdk_pixbuf_animation_new_from_stream (GInputStream *stream
,GCancellable *cancellable
,GError **error
);
Creates a new animation by loading it from an input stream.
The file format is detected automatically. If NULL
is returned, then
error
will be set. The cancellable
can be used to abort the operation
from another thread. If the operation was cancelled, the error
G_IO_ERROR_CANCELLED
will be returned. Other possible errors are in
the GDK_PIXBUF_ERROR and G_IO_ERROR
domains.
The stream is not closed.
Parameters
stream |
a GInputStream to load the pixbuf from |
|
cancellable |
optional GCancellable object, |
[allow-none] |
error |
Return location for an error |
Returns
A newly-created pixbuf, or NULL
if any of several error
conditions occurred: the file could not be opened, the image format is
not supported, there was not enough memory to allocate the image buffer,
the stream contained invalid data, or the operation was cancelled.
Since: 2.28
gdk_pixbuf_animation_new_from_stream_async ()
void gdk_pixbuf_animation_new_from_stream_async (GInputStream *stream
,GCancellable *cancellable
,GAsyncReadyCallback callback
,gpointer user_data
);
Creates a new animation by asynchronously loading an image from an input stream.
For more details see gdk_pixbuf_new_from_stream()
, which is the synchronous
version of this function.
When the operation is finished, callback
will be called in the main thread.
You can then call gdk_pixbuf_animation_new_from_stream_finish()
to get the
result of the operation.
Parameters
stream |
a GInputStream from which to load the animation |
|
cancellable |
optional GCancellable object, |
[allow-none] |
callback |
a GAsyncReadyCallback to call when the pixbuf is loaded |
|
user_data |
the data to pass to the callback function |
Since: 2.28
gdk_pixbuf_animation_new_from_stream_finish ()
GdkPixbufAnimation * gdk_pixbuf_animation_new_from_stream_finish (GAsyncResult *async_result
,GError **error
);
Finishes an asynchronous pixbuf animation creation operation started with
gdk_pixbuf_animation_new_from_stream_async()
.
Since: 2.28
gdk_pixbuf_animation_ref ()
GdkPixbufAnimation *
gdk_pixbuf_animation_ref (GdkPixbufAnimation *animation
);
gdk_pixbuf_animation_ref
has been deprecated since version 2.0 and should not be used in newly-written code.
Use g_object_ref()
.
Adds a reference to an animation.
[skip]
gdk_pixbuf_animation_unref ()
void
gdk_pixbuf_animation_unref (GdkPixbufAnimation *animation
);
gdk_pixbuf_animation_unref
has been deprecated since version 2.0 and should not be used in newly-written code.
Use g_object_unref()
.
Removes a reference from an animation.
[skip]
gdk_pixbuf_animation_get_width ()
int
gdk_pixbuf_animation_get_width (GdkPixbufAnimation *animation
);
Queries the width of the bounding box of a pixbuf animation.
gdk_pixbuf_animation_get_height ()
int
gdk_pixbuf_animation_get_height (GdkPixbufAnimation *animation
);
Queries the height of the bounding box of a pixbuf animation.
gdk_pixbuf_animation_get_iter ()
GdkPixbufAnimationIter * gdk_pixbuf_animation_get_iter (GdkPixbufAnimation *animation
,const GTimeVal *start_time
);
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 g_object_unref()
.
start_time
would normally come from g_get_current_time()
, and marks
the beginning of animation playback. After creating an iterator, you
should immediately display the pixbuf returned by
gdk_pixbuf_animation_iter_get_pixbuf()
. Then, you should install
a timeout (with g_timeout_add()
) or by some other mechanism ensure
that you'll update the image after
gdk_pixbuf_animation_iter_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 NULL
, the result of
g_get_current_time()
will be used automatically.
To update the image (i.e. possibly change the result of
gdk_pixbuf_animation_iter_get_pixbuf()
to a new frame of the animation),
call gdk_pixbuf_animation_iter_advance()
.
If you're using GdkPixbufLoader, in addition to updating the image
after the delay time, you should also update it whenever you
receive the area_updated signal and
gdk_pixbuf_animation_iter_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."
gdk_pixbuf_animation_is_static_image ()
gboolean
gdk_pixbuf_animation_is_static_image (GdkPixbufAnimation *animation
);
If you load a file with gdk_pixbuf_animation_new_from_file()
and it
turns out to be a plain, unanimated image, then this function will
return TRUE
. Use gdk_pixbuf_animation_get_static_image()
to retrieve
the image.
gdk_pixbuf_animation_get_static_image ()
GdkPixbuf *
gdk_pixbuf_animation_get_static_image (GdkPixbufAnimation *animation
);
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 NULL
.
gdk_pixbuf_animation_iter_advance ()
gboolean gdk_pixbuf_animation_iter_advance (GdkPixbufAnimationIter *iter
,const GTimeVal *current_time
);
Possibly advances an animation to a new frame. Chooses the frame based
on the start time passed to gdk_pixbuf_animation_get_iter()
.
current_time
would normally come from g_get_current_time()
, and
must be greater than or equal to the time passed to
gdk_pixbuf_animation_get_iter()
, and must increase or remain
unchanged each time gdk_pixbuf_animation_iter_get_pixbuf()
is
called. That is, you can't go backward in time; animations only
play forward.
As a shortcut, pass NULL
for the current time and g_get_current_time()
will be invoked on your behalf. So you only need to explicitly pass
current_time
if you're doing something odd like playing the animation
at double speed.
If this function returns FALSE
, there's no need to update the animation
display, assuming the display had been rendered prior to advancing;
if TRUE
, you need to call gdk_pixbuf_animation_iter_get_pixbuf()
and update the display with the new pixbuf.
gdk_pixbuf_animation_iter_get_delay_time ()
int
gdk_pixbuf_animation_iter_get_delay_time
(GdkPixbufAnimationIter *iter
);
Gets the number of milliseconds the current pixbuf should be displayed,
or -1 if the current pixbuf should be displayed forever. g_timeout_add()
conveniently takes a timeout in milliseconds, so you can use a timeout
to schedule the next update.
Note that some formats, like GIF, might clamp the timeout values in the image file to avoid updates that are just too quick. The minimum timeout for GIF images is currently 20 milliseconds.
gdk_pixbuf_animation_iter_on_currently_loading_frame ()
gboolean
gdk_pixbuf_animation_iter_on_currently_loading_frame
(GdkPixbufAnimationIter *iter
);
Used to determine how to respond to the area_updated signal on GdkPixbufLoader when loading an animation. area_updated is emitted for an area of the frame currently streaming in to the loader. So if you're on the currently loading frame, you need to redraw the screen for the updated area.
gdk_pixbuf_animation_iter_get_pixbuf ()
GdkPixbuf *
gdk_pixbuf_animation_iter_get_pixbuf (GdkPixbufAnimationIter *iter
);
Gets the current pixbuf which should be displayed; the pixbuf might not
be the same size as the animation itself
(gdk_pixbuf_animation_get_width()
, gdk_pixbuf_animation_get_height()
).
This pixbuf should be displayed for
gdk_pixbuf_animation_iter_get_delay_time()
milliseconds. The caller
of this function does not own a reference to the returned pixbuf;
the returned pixbuf will become invalid when the iterator advances
to the next frame, which may happen anytime you call
gdk_pixbuf_animation_iter_advance()
. Copy the pixbuf to keep it
(don't just add a reference), as it may get recycled as you advance
the iterator.
gdk_pixbuf_simple_anim_new ()
GdkPixbufSimpleAnim * gdk_pixbuf_simple_anim_new (gint width
,gint height
,gfloat rate
);
Creates a new, empty animation.
Parameters
width |
the width of the animation |
|
height |
the height of the animation |
|
rate |
the speed of the animation, in frames per second |
Since: 2.8
gdk_pixbuf_simple_anim_add_frame ()
void gdk_pixbuf_simple_anim_add_frame (GdkPixbufSimpleAnim *animation
,GdkPixbuf *pixbuf
);
Adds a new frame to animation
. The pixbuf
must
have the dimensions specified when the animation
was constructed.
Since: 2.8
gdk_pixbuf_simple_anim_set_loop ()
void gdk_pixbuf_simple_anim_set_loop (GdkPixbufSimpleAnim *animation
,gboolean loop
);
Sets whether animation
should loop indefinitely when it reaches the end.
Since: 2.18
gdk_pixbuf_simple_anim_get_loop ()
gboolean
gdk_pixbuf_simple_anim_get_loop (GdkPixbufSimpleAnim *animation
);
Gets whether animation
should loop indefinitely when it reaches the end.
Since: 2.18
Types and Values
struct GdkPixbufAnimationIter
struct GdkPixbufAnimationIter;
An opaque struct representing an iterator which points to a certain position in an animation.
Property Details
The “loop”
property
“loop” gboolean
Whether the animation should loop when it reaches the end.
Owner: GdkPixbufSimpleAnim
Flags: Read / Write
Default value: FALSE
Since: 2.18