BtSong

BtSong — class of a song project object (contains BtSongInfo, BtSetup, BtSequence and BtWavetable)

Synopsis

#include <libbtcore/core.h>

                    BtSong;
                    BtSongClass;
BtSong *            bt_song_new                         (const BtApplication * const app);
void                bt_song_set_unsaved                 (const BtSong * const self,
                                                         const gboolean unsaved);
gboolean            bt_song_play                        (const BtSong * const self);
gboolean            bt_song_stop                        (const BtSong * const self);
gboolean            bt_song_pause                       (const BtSong * const self);
gboolean            bt_song_continue                    (const BtSong * const self);
gboolean            bt_song_update_playback_position    (const BtSong * const self);
void                bt_song_write_to_xml_file           (const BtSong * const self);
void                bt_song_write_to_highlevel_dot_file (const BtSong * const self);
void                bt_song_write_to_lowlevel_dot_file  (const BtSong * const self);

Object Hierarchy

  GObject
   +----BtSong

Implemented Interfaces

BtSong implements BtPersistence.

Properties

  "app"                      BtApplication*        : Read / Write / Construct Only
  "bin"                      GstBin*               : Read
  "is-idle"                  gboolean              : Read / Write
  "is-playing"               gboolean              : Read
  "master"                   BtSinkMachine*        : Read / Write
  "play-pos"                 gulong                : Read / Write
  "play-rate"                gdouble               : Read / Write
  "sequence"                 BtSequence*           : Read
  "setup"                    BtSetup*              : Read
  "song-info"                BtSongInfo*           : Read
  "song-io"                  BtSongIO*             : Read / Write
  "unsaved"                  gboolean              : Read / Write
  "wavetable"                BtWavetable*          : Read

Description

A song is the top-level container object to manage all song-related objects.

To load or save a song, use a BtSongIO object. These implement loading and saving for different file-formats.

Details

BtSong

typedef struct _BtSong BtSong;

Song project object (contains BtSongInfo, BtSetup and BtSequence)


BtSongClass

typedef struct {
  const GObjectClass parent;
} BtSongClass;

Base class for songs

const GObjectClass parent;

parent class type

bt_song_new ()

BtSong *            bt_song_new                         (const BtApplication * const app);

Create a new instance. The new song instance automatically has one instance of BtSetup, BtSequence and BtSongInfo. These instances can be retrieved via the respecting properties.

For example use following code to retrive a BtSequence from the song class:

BtSequence *sequence;
...
g_object_get(BT_SONG(song), "sequence", &sequence, NULL);

app :

the application object the songs belongs to.

Returns :

the new instance or NULL in case of an error

bt_song_set_unsaved ()

void                bt_song_set_unsaved                 (const BtSong * const self,
                                                         const gboolean unsaved);

Use this method instead of directly setting the state via g_object_set() to avoid double notifies, if the state is unchanged.

self :

the song that should be changed

unsaved :

the new state of the songs unsaved flag

bt_song_play ()

gboolean            bt_song_play                        (const BtSong * const self);

Starts to play the specified song instance from beginning. This methods emits the "play" signal.

self :

the song that should be played

Returns :

TRUE for success

bt_song_stop ()

gboolean            bt_song_stop                        (const BtSong * const self);

Stops the playback of the specified song instance.

self :

the song that should be stopped

Returns :

TRUE for success

bt_song_pause ()

gboolean            bt_song_pause                       (const BtSong * const self);

Pauses the playback of the specified song instance.

self :

the song that should be paused

Returns :

TRUE for success

bt_song_continue ()

gboolean            bt_song_continue                    (const BtSong * const self);

Continues the playback of the specified song instance.

self :

the song that should be paused

Returns :

TRUE for success

bt_song_update_playback_position ()

gboolean            bt_song_update_playback_position    (const BtSong * const self);

Updates the playback-position counter to fire all notify::playback-pos handlers.

self :

the song that should update its playback-pos counter

Returns :

FALSE if the song is not playing

bt_song_write_to_xml_file ()

void                bt_song_write_to_xml_file           (const BtSong * const self);

To aid debugging applications one can use this method to write out the whole network of gstreamer elements that form the song into an XML file. The file will be written to '/tmp' and will be named according the 'name' property of the BtSongInfo. This XML file can be loaded into gst-editor.

self :

the song that should be written

bt_song_write_to_highlevel_dot_file ()

void                bt_song_write_to_highlevel_dot_file (const BtSong * const self);

To aid debugging applications one can use this method to write out the whole network of gstreamer elements from the songs perspective into an dot file. The file will be written to '/tmp' and will be named according the 'name' property of the BtSongInfo. This file can be processed with graphviz to get an image.

 dot -Tpng -oimage.png graph_highlevel.dot

self :

the song that should be written

bt_song_write_to_lowlevel_dot_file ()

void                bt_song_write_to_lowlevel_dot_file  (const BtSong * const self);

To aid debugging applications one can use this method to write out the whole network of gstreamer elements that form the song into an dot file. The file will be written to '/tmp' and will be named according the 'name' property of the BtSongInfo. This file can be processed with graphviz to get an image.

 dot -Tpng -oimage.png graph_lowlevel.dot

self :

the song that should be written

Property Details

The "app" property

  "app"                      BtApplication*        : Read / Write / Construct Only

set application object, the song belongs to.


The "bin" property

  "bin"                      GstBin*               : Read

songs top-level GstElement container.


The "is-idle" property

  "is-idle"                  gboolean              : Read / Write

request that the song should idle-loop if not playing.

Default value: FALSE


The "is-playing" property

  "is-playing"               gboolean              : Read

tell whether the song is playing right now or not.

Default value: FALSE


The "master" property

  "master"                   BtSinkMachine*        : Read / Write

songs audio_sink.


The "play-pos" property

  "play-pos"                 gulong                : Read / Write

position of the play cursor of the sequence in timeline bars.

Allowed values: <= G_MAXLONG


The "play-rate" property

  "play-rate"                gdouble               : Read / Write

playback rate of the sequence.

Allowed values: [-5,5]

Default value: 1


The "sequence" property

  "sequence"                 BtSequence*           : Read

songs sequence sub object.


The "setup" property

  "setup"                    BtSetup*              : Read

songs setup sub object.


The "song-info" property

  "song-info"                BtSongInfo*           : Read

songs metadata sub object.


The "song-io" property

  "song-io"                  BtSongIO*             : Read / Write

the song-io plugin during i/o operations.


The "unsaved" property

  "unsaved"                  gboolean              : Read / Write

tell whether the current state of the song has been saved.

Default value: TRUE


The "wavetable" property

  "wavetable"                BtWavetable*          : Read

songs wavetable sub object.