view plugin/api/alsa/seq_midi_event.h @ 1196:c7b9c902642f spectrogram-minor-refactor

Fix threshold in spectrogram -- it wasn't working in the last release.
There is a new protocol for this. Formerly the threshold parameter had a
range from -50dB to 0 with the default at -50, and -50 treated internally
as "no threshold". However, there was a hardcoded, hidden internal threshold
for spectrogram colour mapping at -80dB with anything below this being rounded
to zero. Now the threshold parameter has range -81 to -1 with the default
at -80, -81 is treated internally as "no threshold", and there is no hidden
internal threshold. So the default behaviour is the same as before, an
effective -80dB threshold, but it is now possible to change this in both
directions. Sessions reloaded from prior versions may look slightly different
because, if the session says there should be no threshold, there will now
actually be no threshold instead of having the hidden internal one.

Still need to do something in the UI to make it apparent that the -81dB
setting removes the threshold entirely. This is at least no worse than the
previous, also obscured, magic -50dB setting.

/* DSSI ALSA compatibility library
 *
 * This library provides for Mac OS X the ALSA snd_seq_event_t handling
 * necessary to compile and run DSSI.  It was extracted from alsa-lib 1.0.8.
 */

/**
 * \file <alsa/seq_midi_event.h>
 * \brief Application interface library for the ALSA driver
 * \author Jaroslav Kysela <[e-mail]>
 * \author Abramo Bagnara <[e-mail]>
 * \author Takashi Iwai <[e-mail]>
 * \date 1998-2001
 *
 * Application interface library for the ALSA driver
 *
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as
 *   published by the Free Software Foundation; either version 2.1 of
 *   the License, or (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public
 *   License along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#ifndef __ALSA_SEQ_MIDI_EVENT_H
#define __ALSA_SEQ_MIDI_EVENT_H

#ifdef __cplusplus
extern "C" {
#endif

/**
 *  \defgroup MIDI_Event Sequencer event <-> MIDI byte stream coder
 *  \ingroup Sequencer
 *  Sequencer event <-> MIDI byte stream coder
 *  \{
 */

/** container for sequencer midi event parsers */
typedef struct snd_midi_event snd_midi_event_t;

int snd_midi_event_new(size_t bufsize, snd_midi_event_t **rdev);
/* int snd_midi_event_resize_buffer(snd_midi_event_t *dev, size_t bufsize); */
void snd_midi_event_free(snd_midi_event_t *dev);
/* void snd_midi_event_init(snd_midi_event_t *dev); */
void snd_midi_event_reset_encode(snd_midi_event_t *dev);
/* void snd_midi_event_reset_decode(snd_midi_event_t *dev); */
/* void snd_midi_event_no_status(snd_midi_event_t *dev, int on); */
/* encode from byte stream - return number of written bytes if success */
long snd_midi_event_encode(snd_midi_event_t *dev, const unsigned char *buf, long count, snd_seq_event_t *ev);
int snd_midi_event_encode_byte(snd_midi_event_t *dev, int c, snd_seq_event_t *ev);
/* decode from event to bytes - return number of written bytes if success */
/* long snd_midi_event_decode(snd_midi_event_t *dev, unsigned char *buf, long count, const snd_seq_event_t *ev); */

/** \} */

#ifdef __cplusplus
}
#endif

#endif /* __ALSA_SEQ_MIDI_EVENT_H */