## BtSequence

BtSequence — class for the event timeline of a BtSong instance

## Synopsis

    #include <libbtcore/core.h>

    struct              BtSequence;
    gboolean            bt_sequence_add_track               (const BtSequence * const self,
                                                             const BtMachine * const machine,
                                                             const glong ix);
    void                bt_sequence_delete_full_rows        (const BtSequence * const self,
                                                             const gulong time,
                                                             const gulong rows);
    void                bt_sequence_delete_rows             (const BtSequence * const self,
                                                             const gulong time,
                                                             const glong track,
                                                             const gulong rows);
    GstClockTime        bt_sequence_get_bar_time            (const BtSequence * const self);
    gchar *             bt_sequence_get_label               (const BtSequence * const self,
                                                             const gulong time);
    GstClockTime        bt_sequence_get_loop_time           (const BtSequence * const self);
    BtMachine *         bt_sequence_get_machine             (const BtSequence * const self,
                                                             const gulong track);
    BtPattern *         bt_sequence_get_pattern             (const BtSequence * const self,
                                                             const gulong time,
                                                             const gulong track);
    glong               bt_sequence_get_tick_by_pattern     (const BtSequence * const self,
                                                             gulong track,
                                                             const BtPattern * const pattern,
                                                             gulong tick);
    glong               bt_sequence_get_track_by_machine    (const BtSequence * const self,
                                                             const BtMachine * const machine,
                                                             gulong track);
    void                bt_sequence_insert_full_rows        (const BtSequence * const self,
                                                             const gulong time,
                                                             const gulong rows);
    void                bt_sequence_insert_rows             (const BtSequence * const self,
                                                             const gulong time,
                                                             const glong track,
                                                             const gulong rows);
    gboolean            bt_sequence_is_pattern_used         (const BtSequence * const self,
                                                             const BtPattern * const pattern);
    gulong              bt_sequence_limit_play_pos          (const BtSequence * const self,
                                                             const gulong play_pos);
    gboolean            bt_sequence_move_track_left         (const BtSequence * const self,
                                                             const gulong track);
    gboolean            bt_sequence_move_track_right        (const BtSequence * const self,
                                                             const gulong track);
    BtSequence *        bt_sequence_new                     (const BtSong * const song);
    gboolean            bt_sequence_remove_track_by_ix      (const BtSequence * const self,
                                                             const gulong ix);
    gboolean            bt_sequence_remove_track_by_machine (const BtSequence * const self,
                                                             const BtMachine * const machine);
    void                bt_sequence_repair_damage           (const BtSequence * const self);
    void                bt_sequence_set_label               (const BtSequence * const self,
                                                             const gulong time,
                                                             const gchar * const label);
    void                bt_sequence_set_pattern             (const BtSequence * const self,
                                                             const gulong time,
                                                             const gulong track,
                                                             const BtPattern * const pattern);
    gboolean            bt_sequence_set_pattern_quick       (const BtSequence * const self,
                                                             const gulong time,
                                                             const gulong track,
                                                             const BtPattern * const pattern);
    void                bt_sequence_update_tempo            (const BtSequence * const self);

## Object Hierarchy

      GObject
       +----BtSequence

## Implemented Interfaces

BtSequence implements

## Properties

      "length"                   gulong                : Read / Write
      "loop"                     gboolean              : Read / Write
      "loop-end"                 glong                 : Read / Write
      "loop-start"               glong                 : Read / Write
      "properties"               gpointer              : Read
      "song"                     BtSong*               : Read / Write / Construct Only
      "tracks"                   gulong                : Read / Write

## Signals

      "pattern-added"                                  : No Hooks
      "pattern-removed"                                : No Hooks
      "rows-changed"                                   : No Hooks
      "track-added"                                    : No Hooks
      "track-removed"                                  : No Hooks

## Description

A sequence holds grid of BtPatterns, with labels on the time axis and BtMachine instances on the track axis. It tracks first and last use of patterns and provides two signals for notification - "pattern-added" and "pattern-removed".

It supports looping a section of the sequence (see "loop", "loop-start", "loop-end").

The BtSequence manages the GstController event queues for the BtMachines and BtWires. It uses a damage-repair based two phase algorithm to update the controller queues whenever patterns or the sequence changes.

## Details

### struct BtSequence

    struct BtSequence;

Starting point for the BtSong timeline data-structures. Holds a series of array of BtPatterns for time and tracks, which define the events that are sent to a BtMachine at a time.

### bt_sequence_add_track ()

    gboolean            bt_sequence_add_track               (const BtSequence * const self,
                                                             const BtMachine * const machine,
                                                             const glong ix);

Adds a new track with the `machine` at `ix` or the end.

`self` : | the BtSequence that holds the tracks
`machine` : | the BtMachine
`ix` : | position to add the track at, use -1 to append
Returns : | `TRUE` for success

### bt_sequence_delete_full_rows ()

    void                bt_sequence_delete_full_rows        (const BtSequence * const self,
                                                             const gulong time,
                                                             const gulong rows);

Delete row for all tracks.

`self` : | the sequence
`time` : | the postion to delete
`rows` : | the number of rows to remove

Since 0.3

### bt_sequence_delete_rows ()

    void                bt_sequence_delete_rows             (const BtSequence * const self,
                                                             const gulong time,
                                                             const glong track,
                                                             const gulong rows);

Delete row for given `track`.

`self` : | the sequence
`time` : | the postion to delete
`track` : | the track
`rows` : | the number of rows to remove

Since 0.3

### bt_sequence_get_bar_time ()

    GstClockTime        bt_sequence_get_bar_time            (const BtSequence * const self);

Calculates the length of one sequence bar in microseconds. Divide it by `G_USEC_PER_SEC` to get it in milliseconds.

`self` : | the BtSequence of the song
Returns : | the length of one sequence bar in microseconds

### bt_sequence_get_label ()

    gchar *             bt_sequence_get_label               (const BtSequence * const self,
                                                             const gulong time);

Fetches the label for the given `time` position. Free when done.

`self` : | the BtSequence that holds the labels
`time` : | the requested time position
Returns : | a copy of the label or `NULL` in case of an error

### bt_sequence_get_loop_time ()

    GstClockTime        bt_sequence_get_loop_time           (const BtSequence * const self);

Calculates the length of the song loop in microseconds. Divide it by `G_USEC_PER_SEC` to get it in milliseconds.

`self` : | the BtSequence of the song
Returns : | the length of the song loop in microseconds

### bt_sequence_get_machine ()

    BtMachine *         bt_sequence_get_machine             (const BtSequence * const self,
                                                             const gulong track);

Fetches the BtMachine for the given `track`. Unref when done.

`self` : | the BtSequence that holds the tracks
`track` : | the requested track index
Returns : | a reference to the BtMachine pointer or `NULL` in case of an error

### bt_sequence_get_pattern ()

    BtPattern *         bt_sequence_get_pattern             (const BtSequence * const self,
                                                             const gulong time,
                                                             const gulong track);

Fetches the pattern for the given `time` and `track` position. Unref when done.

`self` : | the BtSequence that holds the patterns
`time` : | the requested time position
`track` : | the requested track index
Returns : | a reference to the BtPattern or `NULL` when empty

### bt_sequence_get_tick_by_pattern ()

    glong               bt_sequence_get_tick_by_pattern     (const BtSequence * const self,
                                                             gulong track,
                                                             const BtPattern * const pattern,
                                                             gulong tick);

Gets the next tick position >= `tick` this `pattern` is on.

`self` : | the sequence to search in
`track` : | the track to search in
`pattern` : | the pattern to find the next track for
`tick` : | the tick position to start the search from
Returns : | the tick position or -1 if there is no further tick for this `pattern`.

Since 0.6

### bt_sequence_get_track_by_machine ()

    glong               bt_sequence_get_track_by_machine    (const BtSequence * const self,
                                                             const BtMachine * const machine,
                                                             gulong track);

Gets the next track >= `track` this `machine` is on.

`self` : | the sequence to search in
`machine` : | the machine to find the next track for
`track` : | the track to start the search from
Returns : | the track-index or -1 if there is no further track for this `machine`.

Since 0.6

### bt_sequence_insert_full_rows ()

    void                bt_sequence_insert_full_rows        (const BtSequence * const self,
                                                             const gulong time,
                                                             const gulong rows);

Insert one empty row for all tracks.

`self` : | the sequence
`time` : | the postion to insert at
`rows` : | the number of rows to insert

Since 0.3

### bt_sequence_insert_rows ()

    void                bt_sequence_insert_rows             (const BtSequence * const self,
                                                             const gulong time,
                                                             const glong track,
                                                             const gulong rows);

Insert one empty row for given `track`.

`self` : | the sequence
`time` : | the postion to insert at
`track` : | the track
`rows` : | the number of rows to insert

Since 0.3

### bt_sequence_is_pattern_used ()

    gboolean            bt_sequence_is_pattern_used         (const BtSequence * const self,
                                                             const BtPattern * const pattern);

Checks if the `pattern` is used in the sequence.

`self` : | the sequence to check for pattern use
`pattern` : | the pattern to check for
Returns : | `TRUE` if `pattern` is used.

### bt_sequence_limit_play_pos ()

    gulong              bt_sequence_limit_play_pos          (const BtSequence * const self,
                                                             const gulong play_pos);

Enforce the playback position to be within loop start and end or the song bounds if there is no loop.

`self` : | the sequence to trim the play position of
`play_pos` : | the time position to lock inbetween loop-boundaries
Returns : | the new `play_pos`

### bt_sequence_move_track_left ()

    gboolean            bt_sequence_move_track_left         (const BtSequence * const self,
                                                             const gulong track);

Move the selected track on column left.

`self` : | the BtSequence that holds the tracks
`track` : | the track to move
Returns : | `TRUE` for success

### bt_sequence_move_track_right ()

    gboolean            bt_sequence_move_track_right        (const BtSequence * const self,
                                                             const gulong track);

Move the selected track on column left.

`self` : | the BtSequence that holds the tracks
`track` : | the track to move
Returns : | `TRUE` for success

### bt_sequence_new ()

    BtSequence *        bt_sequence_new                     (const BtSong * const song);

Create a new instance. One would not call this directly, but rather get this from a BtSong instance.

`song` : | the song the new instance belongs to
Returns : | the new instance or `NULL` in case of an error

### bt_sequence_remove_track_by_ix ()

    gboolean            bt_sequence_remove_track_by_ix      (const BtSequence * const self,
                                                             const gulong ix);

Removes the specified `track`.

`self` : | the BtSequence that holds the tracks
`ix` : | the requested track index
Returns : | `TRUE` for success

### bt_sequence_remove_track_by_machine ()

    gboolean            bt_sequence_remove_track_by_machine (const BtSequence * const self,
                                                             const BtMachine * const machine);

Removes all tracks that belong the the given `machine`.

`self` : | the BtSequence that holds the tracks
`machine` : | the BtMachine
Returns : | `TRUE` for success

### bt_sequence_repair_damage ()

    void                bt_sequence_repair_damage           (const BtSequence * const self);

Works through the repair queue and rebuilds controller queues, where needed.

There is usualy no need to call that manualy. Only call after soing mass updates using `bt_sequence_set_pattern_quick()` functions.

`self` : | the BtSequence

Since 0.5

### bt_sequence_set_label ()

    void                bt_sequence_set_label               (const BtSequence * const self,
                                                             const gulong time,
                                                             const gchar * const label);

Sets a new label for the respective `time` position.

`self` : | the BtSequence that holds the labels
`time` : | the requested time position
`label` : | the new label

### bt_sequence_set_pattern ()

    void                bt_sequence_set_pattern             (const BtSequence * const self,
                                                             const gulong time,
                                                             const gulong track,
                                                             const BtPattern * const pattern);

Sets the BtPattern for the respective `time` and `track` position.

`self` : | the BtSequence that holds the patterns
`time` : | the requested time position
`track` : | the requested track index
`pattern` : | the BtPattern or `NULL` to unset

### bt_sequence_set_pattern_quick ()

    gboolean            bt_sequence_set_pattern_quick       (const BtSequence * const self,
                                                             const gulong time,
                                                             const gulong track,
                                                             const BtPattern * const pattern);

A quick version of `bt_sequence_set_pattern()` that does not repair damaged area. Useful when doing mass updates.

`self` : | the BtSequence that holds the patterns
`time` : | the requested time position
`track` : | the requested track index
`pattern` : | the BtPattern or `NULL` to unset
Returns : | `TRUE` if a change has been made. One should call `bt_sequence_repair_damage()` in that case.

Since 0.5

### bt_sequence_update_tempo ()

    void                bt_sequence_update_tempo            (const BtSequence * const self);

Refresh sequence after tempo changes. Called from BtSongInfo.

`self` : | the sequence

## Property Details

### The `"length"` property

      "length"                   gulong                : Read / Write

length of the sequence in timeline bars.

Allowed values: <= G_MAXLONG

### The `"loop"` property

      "loop"                     gboolean              : Read / Write

is loop activated.

Default value: FALSE

### The `"loop-end"` property

      "loop-end"                 glong                 : Read / Write

end of the repeat sequence on the timeline.

Allowed values: >= -1

Default value: -1

### The `"loop-start"` property

      "loop-start"               glong                 : Read / Write

start of the repeat sequence on the timeline.

Allowed values: >= -1

Default value: -1

### The `"properties"` property

      "properties"               gpointer              : Read

hashtable of sequence properties.

### The `"song"` property

      "song"                     BtSong*               : Read / Write / Construct Only

Set song object, the sequence belongs to.

### The `"tracks"` property

      "tracks"                   gulong                : Read / Write

number of tracks in the sequence.

## Signal Details

### The `"pattern-added"` signal

    void                user_function                      (BtSequence *self,
                                                            BtPattern  *pattern,
                                                            gpointer    user_data)      : No Hooks

A pattern has been used in the sequence for the first time.

`self` : | the sequence object that emitted the signal
`pattern` : | the new pattern
`user_data` : | user data set when the signal handler was connected.

### The `"pattern-removed"` signal

    void                user_function                      (BtSequence *self,
                                                            BtPattern  *pattern,
                                                            gpointer    user_data)      : No Hooks

The last occurance of pattern has been removed from the sequence.

`self` : | the sequence object that emitted the signal
`pattern` : | the old pattern
`user_data` : | user data set when the signal handler was connected.

### The `"rows-changed"` signal

    void                user_function                      (BtSequence *self,
                                                            gulong      begin,
                                                            gulong      end,
                                                            gpointer    user_data)      : No Hooks

The content of the given rows in the sequence has changed.

`self` : | the sequence object that emitted the signal
`begin` : | start row that changed
`end` : | last row that changed
`user_data` : | user data set when the signal handler was connected.

Since 0.6

### The `"track-added"` signal

    void                user_function                      (BtSequence *self,
                                                            BtMachine  *machine,
                                                            gulong      track,
                                                            gpointer    user_data)      : No Hooks

A new track for `machine` has been added with the `track` index.

`self` : | the sequence object that emitted the signal
`machine` : | the machine for the track
`track` : | the track index
`user_data` : | user data set when the signal handler was connected.

Since 0.6

### The `"track-removed"` signal

    void                user_function                      (BtSequence *self,
                                                            BtMachine  *machine,
                                                            gulong      track,
                                                            gpointer    user_data)      : No Hooks

A track for `machine` has been removed at the `track` index.

`self` : | the sequence object that emitted the signal
`machine` : | the machine for the track
`track` : | the track index
`user_data` : | user data set when the signal handler was connected.

Since 0.6