=head1 NAME

Tk::Animation - Display sequence of Tk::Photo images

=for pm Tk/Animation.pm

=for category Tk Image Classes


  use Tk::Animation
  my $img = $widget->Animation('-format' => 'gif', -file => 'somefile.gif');


  $img->start_animation( $period );

  $img->set_image( 0 .. $#frames );

  $img->resume_animation( $period );

  $img->fast_forward( $multiplier );
  $img->fast_reverse( $multiplier );


  $img->set_disposal_method( $boolean );


In the simple case when C<Animation> is passed a GIF89 style GIF with
multiple 'frames', it will build an internal array of C<Photo> images.

The C<add_frame> method adds images to the sequence. It is provided
to allow animations to be constructed from separate images.
All images must be C<Photo>s and should all be the same size.

C<start_animation($period)> then initiates a C<repeat> with specified
I<$period> to sequence through these images. As for raw C<repeat>
I<$period> is in milliseconds, for a 50Hz monitor it should be at
least 20ms. If I<$period> is omitted it is determined from the GIF
metadata (see below), or if this is not possible it defaults to 100

C<stop_animation> cancels the C<repeat> and resets the image to the first
image in the sequence.

For fine-grained control C<next_image> and C<prev_image> move one frame forward
or backward.  C<set_image> randomly positions the animation to a particular frame.

C<pause_animation> pauses the movie and C<resume_animation> continues from the
pause point.

C<fast_forward> and C<fast_reverse> speed through the movie either
forwards or backwards.  $multiplier specifies how much faster the
animation moves.

If L<Image::Info> is installed, then the repeat period time and
disposal method of GIF animations are determined from the GIF metadata
directly. Otherwise the disposal method must be set manually by using
C<set_disposal_method> (1 for blanking the previous images, 0 for
leaving the previous images as is). The repeat period time may be
given in the C<start_animation> method.

=head1 NOTES

C<set_disposal_method> was formerly known as C<blank> method, but the
naming of this method was a mistake.

If the disposal method is not set correctly, either by
C<set_disposal_method> or by determining from the GIF metadata, then
the following may happen: By default Animation leaves the previous
movie frame in the animation photo. Many times overlaying subsequent
frames produces a composite that looks blurred.

=head1 BUGS

This module should not depend on a module which is not declared as a
dependency (Image::Info).

The delays between images may vary in a GIF animation. This cannot be
handled by this module yet.

The handling of the various disposal methods is not correct.