Class: GdkPixbuf::PixbufAnimationIter

Inherits:
Object
  • Object
show all
Defined in:
(unknown)

Overview

Modules supporting animations must derive a type from
Gdk::PixbufAnimationIter, providing suitable implementations of the
virtual functions.

Direct Known Subclasses

PixbufSimpleAnimIter

Instance Method Summary collapse

Instance Method Details

#advance(current_time) ⇒ Boolean

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.

Parameters:

  • current_time (GLib::TimeVal) —

    current time

Returns:

  • (Boolean) —

    TRUE if the image may need updating

#delay_time ⇒ Integer

Gets the number of milliseconds the current pixbuf should be displayed,
or -1 if the current pixbuf should be displayed forever.

The g_timeout_add() function 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.

Returns:

  • (Integer) —

    delay time in milliseconds (thousandths of a second)

#on_currently_loading_frame ⇒ Boolean

Used to determine how to respond to the area_updated signal on
Gdk::PixbufLoader when loading an animation.

The ::area_updated signal is emitted for an area of the frame currently
streaming in to the loader. So if you're on the currently loading frame,
you will need to redraw the screen for the updated area.

Returns:

  • (Boolean) —

    TRUE if the frame we're on is partially loaded, or the last frame

#pixbuf ⇒ GdkPixbuf::Pixbuf

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.

Returns: