Aegisub/aegisub/libass/ass.h

375 lines
11 KiB
C

/*
* 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 <stdarg.h>
#include "ass_types.h"
#define LIBASS_VERSION 0x00908000
/*
* A linked list of images produced by an ass renderer.
*
* These images have to be rendered in-order for the correct screen
* composition. The libass renderer clips these bitmaps to the frame size.
* w/h can be zero, in this case the bitmap should not be rendered at all.
* The last bitmap row is not guaranteed to be padded up to stride size,
* e.g. in the worst case a bitmap has the size stride * (h - 1) + w.
*/
typedef struct ass_image {
int w, h; // Bitmap width/height
int stride; // Bitmap stride
unsigned char *bitmap; // 1bpp stride*h alpha buffer
// Note: the last row may not be padded to
// bitmap stride!
uint32_t color; // Bitmap color and alpha, RGBA
int dst_x, dst_y; // Bitmap placement inside the video frame
struct ass_image *next; // Next image, or NULL
} ASS_Image;
/*
* Hinting type. (see ass_set_hinting below)
*
* FreeType's native hinter is still buggy sometimes and it is recommended
* to use the light autohinter, ASS_HINTING_LIGHT, instead. For best
* compatibility with problematic fonts, disable hinting.
*/
typedef enum {
ASS_HINTING_NONE = 0,
ASS_HINTING_LIGHT,
ASS_HINTING_NORMAL,
ASS_HINTING_NATIVE
} ASS_Hinting;
/**
* \brief Initialize the library.
* \return library handle or NULL if failed
*/
ASS_Library *ass_library_init(void);
/**
* \brief Finalize the library
* \param priv library handle
*/
void ass_library_done(ASS_Library *priv);
/**
* \brief Set private font directory.
* It is used for saving embedded fonts and also in font lookup.
*
* \param priv library handle
* \param fonts_dir private directory for font extraction
*/
void ass_set_fonts_dir(ASS_Library *priv, const char *fonts_dir);
/**
* \brief Whether fonts should be extracted from track data.
* \param priv library handle
* \param extract whether to extract fonts
*/
void ass_set_extract_fonts(ASS_Library *priv, int extract);
/**
* \brief Register style overrides with a library instance.
* The overrides should have the form [Style.]Param=Value, e.g.
* SomeStyle.Font=Arial
* ScaledBorderAndShadow=yes
*
* \param priv library handle
* \param list NULL-terminated list of strings
*/
void ass_set_style_overrides(ASS_Library *priv, char **list);
/**
* \brief Explicitly process style overrides for a track.
* \param track track handle
*/
void ass_process_force_style(ASS_Track *track);
/**
* \brief Register a callback for debug/info messages.
* If a callback is registered, it is called for every message emitted by
* libass. The callback receives a format string and a list of arguments,
* to be used for the printf family of functions. Additionally, a log level
* from 0 (FATAL errors) to 7 (verbose DEBUG) is passed. Usually, level 5
* should be used by applications.
* If no callback is set, all messages level < 5 are printed to stderr,
* prefixed with [ass].
*
* \param priv library handle
* \param msg_cb pointer to callback function
* \param data additional data, will be passed to callback
*/
void ass_set_message_cb(ASS_Library *priv, void (*msg_cb)
(int level, const char *fmt, va_list args, void *data),
void *data);
/**
* \brief Initialize the renderer.
* \param priv library handle
* \return renderer handle or NULL if failed
*/
ASS_Renderer *ass_renderer_init(ASS_Library *);
/**
* \brief Finalize the renderer.
* \param priv renderer handle
*/
void ass_renderer_done(ASS_Renderer *priv);
/**
* \brief Set the frame size in pixels, including margins.
* \param priv renderer handle
* \param w width
* \param h height
*/
void ass_set_frame_size(ASS_Renderer *priv, int w, int h);
/**
* \brief Set frame margins. These values may be negative if pan-and-scan
* is used.
* \param priv renderer handle
* \param t top margin
* \param b bottom margin
* \param l left margin
* \param r right margin
*/
void ass_set_margins(ASS_Renderer *priv, int t, int b, int l, int r);
/**
* \brief Whether margins should be used for placing regular events.
* \param priv renderer handle
* \param use whether to use the margins
*/
void ass_set_use_margins(ASS_Renderer *priv, int use);
/**
* \brief Set aspect ratio parameters.
* \param priv renderer handle
* \param dar display aspect ratio (DAR), prescaled for output PAR
* \param sar storage aspect ratio (SAR)
*/
void ass_set_aspect_ratio(ASS_Renderer *priv, double dar, double sar);
/**
* \brief Set a fixed font scaling factor.
* \param priv renderer handle
* \param font_scale scaling factor, default is 1.0
*/
void ass_set_font_scale(ASS_Renderer *priv, double font_scale);
/**
* \brief Set font hinting method.
* \param priv renderer handle
* \param ht hinting method
*/
void ass_set_hinting(ASS_Renderer *priv, ASS_Hinting ht);
/**
* \brief Set line spacing. Will not be scaled with frame size.
* \param priv renderer handle
* \param line_spacing line spacing in pixels
*/
void ass_set_line_spacing(ASS_Renderer *priv, double line_spacing);
/**
* \brief Set font lookup defaults.
* \param default_font path to default font to use. Must be supplied if
* fontconfig is disabled or unavailable.
* \param default_family fallback font family for fontconfig, or NULL
* \param fc whether to use fontconfig
* \param config path to fontconfig configuration file, or NULL. Only relevant
* if fontconfig is used.
* \param update whether fontconfig cache should be built/updated now. Only
* relevant if fontconfig is used.
*/
void ass_set_fonts(ASS_Renderer *priv, const char *default_font,
const char *default_family, int fc, const char *config,
int update);
/**
* \brief Update/build font cache. This needs to be called if it was
* disabled when ass_set_fonts was set.
*
* \param priv renderer handle
* \return success
*/
int ass_fonts_update(ASS_Renderer *priv);
/**
* \brief Set hard cache limits. Do not set, or set to zero, for reasonable
* defaults.
*
* \param priv renderer handle
* \param glyph_max maximum number of cached glyphs
* \param bitmap_max_size maximum bitmap cache size (in MB)
*/
void ass_set_cache_limits(ASS_Renderer *priv, int glyph_max,
int bitmap_max_size);
/**
* \brief Render a frame, producing a list of ASS_Image.
* \param priv renderer handle
* \param track subtitle track
* \param now video timestamp in milliseconds
* \param detect_change will be set to 1 if a change occured compared
* to the last invocation
*/
ASS_Image *ass_render_frame(ASS_Renderer *priv, ASS_Track *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.
* \param library handle
* \return pointer to empty track
*/
ASS_Track *ass_new_track(ASS_Library *);
/**
* \brief Deallocate track and all its child objects (styles and events).
* \param track track to deallocate
*/
void ass_free_track(ASS_Track *track);
/**
* \brief Allocate new style.
* \param track track
* \return newly allocated style id
*/
int ass_alloc_style(ASS_Track *track);
/**
* \brief Allocate new event.
* \param track track
* \return newly allocated event id
*/
int ass_alloc_event(ASS_Track *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 *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 *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 *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 *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 *track, char *data, int size,
long long timecode, long long duration);
/**
* \brief Read subtitles from file.
* \param library library handle
* \param fname file name
* \param codepage encoding (iconv format)
* \return newly allocated track
*/
ASS_Track *ass_read_file(ASS_Library *library, char *fname,
char *codepage);
/**
* \brief Read subtitles from memory.
* \param library library handle
* \param buf pointer to subtitles text
* \param bufsize size of buffer
* \param codepage encoding (iconv format)
* \return newly allocated track
*/
ASS_Track *ass_read_memory(ASS_Library *library, char *buf,
size_t bufsize, char *codepage);
/**
* \brief Read styles from file into already initialized track.
* \param fname file name
* \param codepage encoding (iconv format)
* \return 0 on success
*/
int ass_read_styles(ASS_Track *track, char *fname, char *codepage);
/**
* \brief Add a memory font.
* \param library library handle
* \param name attachment name
* \param data binary font data
* \param data_size data size
*/
void ass_add_font(ASS_Library *library, char *name, char *data,
int data_size);
/**
* \brief Remove all fonts stored in an ass_library object.
* \param library library handle
*/
void ass_clear_fonts(ASS_Library *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 in milliseconds
* \param movement how many events to skip from the one currently displayed
* +2 means "the one after the next", -1 means "previous"
* \return timeshift in milliseconds
*/
long long ass_step_sub(ASS_Track *track, long long now, int movement);
#endif /* LIBASS_ASS_H */