The gdk-pixbuf Library | ||||
---|---|---|---|---|
#include <gdk-pixbuf/gdk-pixbuf.h> GdkPixbufAnimation; GdkPixbufAnimationIter; GdkPixbufAnimation* gdk_pixbuf_animation_new_from_file (const char *filename, GError **error); GdkPixbufAnimation* gdk_pixbuf_animation_ref (GdkPixbufAnimation *animation); void gdk_pixbuf_animation_unref (GdkPixbufAnimation *animation); int gdk_pixbuf_animation_get_width (GdkPixbufAnimation *animation); int gdk_pixbuf_animation_get_height (GdkPixbufAnimation *animation); GdkPixbufAnimationIter* gdk_pixbuf_animation_get_iter (GdkPixbufAnimation *animation, const GTimeVal *start_time); gboolean gdk_pixbuf_animation_is_static_image (GdkPixbufAnimation *animation); GdkPixbuf* gdk_pixbuf_animation_get_static_image (GdkPixbufAnimation *animation); gboolean gdk_pixbuf_animation_iter_advance (GdkPixbufAnimationIter *iter, const GTimeVal *current_time); int gdk_pixbuf_animation_iter_get_delay_time (GdkPixbufAnimationIter *iter); gboolean gdk_pixbuf_animation_iter_on_currently_loading_frame (GdkPixbufAnimationIter *iter); GdkPixbuf* gdk_pixbuf_animation_iter_get_pixbuf (GdkPixbufAnimationIter *iter); GdkPixbufSimpleAnim; GdkPixbufSimpleAnim* gdk_pixbuf_simple_anim_new (gint width, gint height, gfloat rate); void gdk_pixbuf_simple_anim_add_frame (GdkPixbufSimpleAnim *animation, GdkPixbuf *pixbuf);
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.
typedef struct _GdkPixbufAnimation GdkPixbufAnimation;
And opaque struct representing an animation.
typedef struct _GdkPixbufAnimationIter GdkPixbufAnimationIter;
And opaque struct representing an iterator which points to a certain position in an animation.
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.
filename : |
Name of file to load, in the GLib file name encoding |
error : |
return location for error |
Returns : | A newly-created animation with a reference count of 1, or NULL
if any of several error conditions ocurred: the file could not be opened,
there was no loader for the file's format, there was not enough memory to
allocate the image buffer, or the image file contained invalid data.
|
GdkPixbufAnimation* gdk_pixbuf_animation_ref (GdkPixbufAnimation *animation);
gdk_pixbuf_animation_ref
is deprecated and should not be used in newly-written code. Use g_object_ref()
.
Adds a reference to an animation.
animation : |
An animation. |
Returns : | The same as the animation argument.
|
void gdk_pixbuf_animation_unref (GdkPixbufAnimation *animation);
gdk_pixbuf_animation_unref
is deprecated and should not be used in newly-written code. Use g_object_unref()
.
Removes a reference from an animation.
animation : |
An animation. |
int gdk_pixbuf_animation_get_width (GdkPixbufAnimation *animation);
Queries the width of the bounding box of a pixbuf animation.
animation : |
An animation. |
Returns : | Width of the bounding box of the animation. |
int gdk_pixbuf_animation_get_height (GdkPixbufAnimation *animation);
Queries the height of the bounding box of a pixbuf animation.
animation : |
An animation. |
Returns : | Height of the bounding box of the animation. |
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."
animation : |
a GdkPixbufAnimation |
start_time : |
time when the animation starts playing |
Returns : | an iterator to move over the animation |
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.
animation : |
a GdkPixbufAnimation |
Returns : | TRUE if the "animation" was really just an 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
.
animation : |
a GdkPixbufAnimation |
Returns : | unanimated image representing the animation |
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_animation_iter_get_pixbuf()
and update the
display with the new pixbuf.
iter : |
a GdkPixbufAnimationIter |
current_time : |
current time |
Returns : | TRUE if the image may need updating
|
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.
iter : |
an animation iterator |
Returns : | delay time in milliseconds (thousandths of a second) |
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.
iter : |
a GdkPixbufAnimationIter |
Returns : | TRUE if the frame we're on is partially loaded, or the last frame
|
GdkPixbuf* gdk_pixbuf_animation_iter_get_pixbuf (GdkPixbufAnimationIter *iter);
Gets the current pixbuf which should be displayed; the pixbuf will
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.
iter : |
an animation iterator |
Returns : | the pixbuf to be displayed |
GdkPixbufSimpleAnim* gdk_pixbuf_simple_anim_new (gint width, gint height, gfloat rate);
Creates a new, empty animation.
width : |
the width of the animation |
height : |
the height of the animation |
rate : |
the speed of the animation, in frames per second |
Returns : | a newly allocated GdkPixbufSimpleAnim |
Since 2.8
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.
animation : |
a GdkPixbufSimpleAnim |
pixbuf : |
the pixbuf to add |
Since 2.8