Aegisub/aegisub/libass/ass.h

/*
 * Copyright (C) 2006 Evgeniy Stepanov <eugeni.stepanov@gmail.com>
 *
 * This file is part of libass.
 *
 * libass 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.
 *
 * libass 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 libass; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef LIBASS_ASS_H
#define LIBASS_ASS_H

#include <stdio.h>
#include "ass_types.h"

/// Libass renderer object. Contents are private.
typedef struct ass_renderer_s ass_renderer_t;

/// a linked list of images produced by ass renderer
typedef struct ass_image_s {
    int w, h;                   // bitmap width/height
    int stride;                 // bitmap stride
    unsigned char *bitmap;      // 1bpp stride*h alpha buffer
    uint32_t color;             // RGBA
    int dst_x, dst_y;           // bitmap placement inside the video frame

    struct ass_image_s *next;   // linked list
} ass_image_t;

/// Hinting type
typedef enum { ASS_HINTING_NONE = 0,
    ASS_HINTING_LIGHT,
    ASS_HINTING_NORMAL,
    ASS_HINTING_NATIVE
} ass_hinting_t;

/**
 * \brief initialize the library
 * \return library handle or NULL if failed
 */
ass_library_t *ass_library_init(void);

/**
 * \brief finalize the library
 * \param priv library handle
 */
void ass_library_done(ass_library_t *);

/**
 * \brief set private font directory
 * It is used for saving embedded fonts and also in font lookup.
 */
void ass_set_fonts_dir(ass_library_t *priv, const char *fonts_dir);

void ass_set_extract_fonts(ass_library_t *priv, int extract);

void ass_set_style_overrides(ass_library_t *priv, char **list);

void ass_process_force_style(ass_track_t *track);

/**
 * \brief initialize the renderer
 * \param priv library handle
 * \return renderer handle or NULL if failed
 */
ass_renderer_t *ass_renderer_init(ass_library_t *);

/**
 * \brief finalize the renderer
 * \param priv renderer handle
 */
void ass_renderer_done(ass_renderer_t *priv);

void ass_set_frame_size(ass_renderer_t *priv, int w, int h);
void ass_set_margins(ass_renderer_t *priv, int t, int b, int l, int r);
void ass_set_use_margins(ass_renderer_t *priv, int use);
void ass_set_aspect_ratio(ass_renderer_t *priv, double ar, double par);
void ass_set_font_scale(ass_renderer_t *priv, double font_scale);
void ass_set_hinting(ass_renderer_t *priv, ass_hinting_t ht);
void ass_set_line_spacing(ass_renderer_t *priv, double line_spacing);

/**
 * \brief set font lookup defaults
 * \param fc bool, use fontconfig?
 * \param config path to fontconfig configuration file, or NULL. Only matters
 * if fontconfig is used
 */
int ass_set_fonts(ass_renderer_t *priv, const char *default_font,
                  const char *default_family, int fc, const char *config);

/**
 * \brief render a frame, producing a list of ass_image_t
 * \param priv library
 * \param track subtitle track
 * \param now video timestamp in milliseconds
 */
ass_image_t *ass_render_frame(ass_renderer_t *priv, ass_track_t *track,
                              long long now, int *detect_change);


// The following functions operate on track objects and do not need an ass_renderer //

/**
 * \brief allocate a new empty track object
 * \return pointer to empty track
 */
ass_track_t *ass_new_track(ass_library_t *);

/**
 * \brief deallocate track and all its child objects (styles and events)
 * \param track track to deallocate
 */
void ass_free_track(ass_track_t *track);

/**
 * \brief allocate new style
 * \param track track
 * \return newly allocated style id
 */
int ass_alloc_style(ass_track_t *track);

/**
 * \brief allocate new event
 * \param track track
 * \return newly allocated event id
 */
int ass_alloc_event(ass_track_t *track);

/**
 * \brief delete a style
 * \param track track
 * \param sid style id
 * Deallocates style data. Does not modify track->n_styles.
 */
void ass_free_style(ass_track_t *track, int sid);

/**
 * \brief delete an event
 * \param track track
 * \param eid event id
 * Deallocates event data. Does not modify track->n_events.
 */
void ass_free_event(ass_track_t *track, int eid);

/**
 * \brief Parse a chunk of subtitle stream data.
 * \param track track
 * \param data string to parse
 * \param size length of data
 */
void ass_process_data(ass_track_t *track, char *data, int size);

/**
 * \brief Parse Codec Private section of subtitle stream
 * \param track target track
 * \param data string to parse
 * \param size length of data
 */
void ass_process_codec_private(ass_track_t *track, char *data, int size);

/**
 * \brief Parse a chunk of subtitle stream data. In Matroska, this contains exactly 1 event (or a commentary).
 * \param track track
 * \param data string to parse
 * \param size length of data
 * \param timecode starting time of the event (milliseconds)
 * \param duration duration of the event (milliseconds)
*/
void ass_process_chunk(ass_track_t *track, char *data, int size,
                       long long timecode, long long duration);

/**
 * \brief Read subtitles from file.
 * \param fname file name
 * \return newly allocated track
*/
ass_track_t *ass_read_file(ass_library_t *library, char *fname,
                           char *codepage);

/**
 * \brief Read subtitles from memory.
 * \param library libass library object
 * \param buf pointer to subtitles text
 * \param bufsize size of buffer
 * \param codepage recode buffer contents from given codepage
 * \return newly allocated track
*/
ass_track_t *ass_read_memory(ass_library_t *library, char *buf,
                             size_t bufsize, char *codepage);
/**
 * \brief read styles from file into already initialized track
 * \return 0 on success
 */
int ass_read_styles(ass_track_t *track, char *fname, char *codepage);

/**
 * \brief Add a memory font.
 * \param name attachment name
 * \param data binary font data
 * \param data_size data size
*/
void ass_add_font(ass_library_t *library, char *name, char *data,
                  int data_size);

/**
 * \brief Remove all fonts stored in ass_library object
 */
void ass_clear_fonts(ass_library_t *library);

/**
 * \brief Calculates timeshift from now to the start of some other subtitle event, depending on movement parameter
 * \param track subtitle track
 * \param now current time, ms
 * \param movement how many events to skip from the one currently displayed
 * +2 means "the one after the next", -1 means "previous"
 * \return timeshift, ms
 */
long long ass_step_sub(ass_track_t *track, long long now, int movement);

#endif                          /* LIBASS_ASS_H */