/* * Copyright (C) 2003-2011 The Music Player Daemon Project * http://www.musicpd.org * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 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 General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ /** \file * * This header declares the mixer_plugin class. It should not be * included directly; use mixer_api.h instead in mixer * implementations. */ #ifndef MPD_MIXER_PLUGIN_H #define MPD_MIXER_PLUGIN_H #include <glib.h> #include <stdbool.h> struct config_param; struct mixer; struct mixer_plugin { /** * Alocates and configures a mixer device. * * @param ao the pointer returned by audio_output_plugin.init * @param param the configuration section, or NULL if there is * no configuration * @param error_r location to store the error occurring, or * NULL to ignore errors * @return a mixer object, or NULL on error */ struct mixer *(*init)(void *ao, const struct config_param *param, GError **error_r); /** * Finish and free mixer data */ void (*finish)(struct mixer *data); /** * Open mixer device * * @param error_r location to store the error occurring, or * NULL to ignore errors * @return true on success, false on error */ bool (*open)(struct mixer *data, GError **error_r); /** * Close mixer device */ void (*close)(struct mixer *data); /** * Reads the current volume. * * @param error_r location to store the error occurring, or * NULL to ignore errors * @return the current volume (0..100 including) or -1 if * unavailable or on error (error_r set, mixer will be closed) */ int (*get_volume)(struct mixer *mixer, GError **error_r); /** * Sets the volume. * * @param error_r location to store the error occurring, or * NULL to ignore errors * @param volume the new volume (0..100 including) * @return true on success, false on error */ bool (*set_volume)(struct mixer *mixer, unsigned volume, GError **error_r); /** * If true, then the mixer is automatically opened, even if * its audio output is not open. If false, then the mixer is * disabled as long as its audio output is closed. */ bool global; }; #endif