subfont.c

/*
    Lowest-level interface to FreeType font rendering. Assumes all text
    to be rendered is UTF-8-encoded.
*/
/* Copyright (C) 2000 - 2003 various authors of the MPLAYER project
 * This module uses various parts of the MPLAYER project (http://www.mplayerhq.hu)
 * With many changes by Sjef van Gool (svangool@hotmail.com) November 2003
 *
 * 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.
 */

/*
 * Renders antialiased fonts for mplayer using freetype library.
 * Should work with TrueType, Type1 and any other font supported by libfreetype.
 *
 * Artur Zaprzala <zybi@fanthom.irc.pl>
 *
 * ported inside mplayer by Jindrich Makovicka
 * <makovick@kmlinux.fjfi.cvut.cz>
 *
 * Major rework by Lawrence D'Oliveiro <ldo@geek-central.gen.nz>.
 *
 */

#include "config.h"


#ifdef HAVE_FREETYPE

#include "compat.h"

#include <math.h>

#include <netinet/in.h>

#include "subglobals.h"
#include "subfont.h"

#include FT_GLYPH_H

#if (FREETYPE_MAJOR > 2) || (FREETYPE_MAJOR == 2 && FREETYPE_MINOR >= 1)
#define HAVE_FREETYPE21
#endif

#if HAVE_FONTCONFIG
#include <fontconfig/fontconfig.h>
#endif /* HAVE_FONTCONFIG */

font_desc_t* vo_font = NULL;

static bool freetype_inited = false;

//// constants
static unsigned int const nr_colors = 256;
static unsigned int const maxcolor = 255;
static unsigned const first_char = 33; /* first non-printable, non-whitespace character */
#define MAX_CHARSET_SIZE 60000 /* hope this is enough! */

static FT_Library library;

#define f266ToInt(x)        (((x)+32)>>6)   // round fractional fixed point number to integer
                        // coordinates are in 26.6 pixels (i.e. 1/64th of pixels)
#define f266CeilToInt(x)    (((x)+63)>>6)   // ceiling
#define f266FloorToInt(x)   ((x)>>6)    // floor
#define f1616ToInt(x)       (((x)+0x8000)>>16)  // 16.16
#define floatTof266(x)      ((int)((x)*(1<<6)+0.5))

#define ALIGN_8BYTES(x)                (((x)+7)&~7)    // 8 byte align

#define WARNING(msg, args...)      fprintf(stderr,"WARN:" msg "\n", ## args)

#define DEBUG 0

//static double ttime;

enum
  { /* predefined colour-table indexes--note can't have more than 4 */
    COLIDX_TRANSPARENT, /* always transparent to let background video through */
    COLIDX_FILL, /* text fill colour */
    COLIDX_OUTLINE, /* text outline colour */
    COLIDX_SHADOW /* text shadow colour */
  };
static int const font_load_flags = FT_LOAD_MONOCHROME | FT_LOAD_RENDER;
  /* worth adding FT_LOAD_TARGET_MONO as well? */
float text_font_scale_factor = 28.0; /* font size in font units */
float subtitle_font_thickness = 3.0;  /*2.0*/
colorspec
    subtitle_fill_color = {255, 255, 255, 255}, /* default opaque white */
    subtitle_outline_color = {0, 0, 0, 255}, /* default opaque black */
    subtitle_shadow_color = {0, 0, 0, 255}; /* default opaque black */
int
    subtitle_shadow_dx = 0,
    subtitle_shadow_dy = 0;

int subtitle_autoscale = AUTOSCALE_NONE;
char *sub_font = /* Name of true type font, windows OS apps will look in \windows\fonts others in home dir */
#if HAVE_FONTCONFIG
    "arial"
#else
    "arial.ttf"
#endif
;

static char *get_config_path(const char *filename)
  /* returns the path at which to find the config file named filename. If this is
    null, then just the config directory is returned. */
  {
    char *homedir;
    char *buff;
#if defined(__MINGW32__) || defined(__CYGWIN__)
    char exedir[260];
    static char *config_dir = "/spumux";
#else
    static char *config_dir = "/.spumux"; /* fixme: should perhaps use xdg base dir stuff in conffile.[ch] */
#endif
    int len;
#if defined(__MINGW32__) || defined(__CYGWIN__)
    if ((homedir = getenv("WINDIR")) != NULL)
        config_dir = "/fonts";
    else
#endif
    if ((homedir = getenv("HOME")) == NULL)
#if defined(__MINGW32__) || defined(__CYGWIN__) /*hack to get fonts etc. loaded outside of cygwin environment*/
      {
        extern int __stdcall GetModuleFileNameA(void* hModule, char* lpFilename, int nSize);
        int i, imax = 0;
        GetModuleFileNameA(NULL, exedir, sizeof exedir);
        for (i = 0; i<   strlen(exedir); i++)
            if (exedir[i] == '\\')
              {
                exedir[i] = '/'; /* translate path separator */
                imax = i;
              } /*if; for*/
        exedir[imax] = '\0'; /* terminate at rightmost path separator */
        homedir = exedir;
  /*    fprintf(stderr, "Homedir %s", homedir); */
      } /*if*/
#else
        return NULL;
#endif
    len = strlen(homedir) + strlen(config_dir) + 1;
    if (filename == NULL)
      {
        if ((buff = (char *)malloc(len)) == NULL)
            return NULL;
        sprintf(buff, "%s%s", homedir, config_dir);
      }
    else
      {
        len += strlen(filename) + 1;
        if ((buff = (char *)malloc(len)) == NULL)
            return NULL;
        sprintf(buff, "%s%s/%s", homedir, config_dir, filename);
      } /*if*/
/*  fprintf(stderr,"INFO: get_config_path('%s') -> '%s'\n",filename,buff); */
    return buff;
  } /*get_config_path*/

static void paste_bitmap
  (
    unsigned char *bbuffer,
    const FT_Bitmap *bitmap,
    int x, /* position from origin of bbuffer */
    int y, /* position from origin of bbuffer */
    int width, /* width of bbuffer */
    int height, /* height of area to copy */
    int bwidth /* width of area to copy */
  )
  /* copies pixels out of bitmap into bbuffer. Used to save glyph images as rendered
    by FreeType into my cache. */
  {
    int drow = x + y * width;
    int srow = 0;
    int sp, dp, w, h;
    if (bitmap->pixel_mode == FT_PIXEL_MODE_MONO)
      /* map one-bit-per-pixel source to indexed pixel */
        for
          (
            h = bitmap->rows;
            h > 0 && height > 0;
            --h, height--, drow += width, srow += bitmap->pitch
          )
            for (w = bwidth, sp = dp = 0; w > 0; --w, ++dp, ++sp)
                bbuffer[drow + dp] =
                    (bitmap->buffer[srow + sp / 8] & 0x80 >> sp % 8) != 0 ?
                        COLIDX_FILL
                    :
                        COLIDX_TRANSPARENT;
    else
      /* assume FT_PIXEL_MODE_GRAY */
        for
          (
            h = bitmap->rows;
            h > 0 && height > 0;
            --h, height--, drow += width, srow += bitmap->pitch
          )
            for (w = bwidth, sp = dp = 0; w > 0; --w, ++dp, ++sp)
                bbuffer[drow + dp] = bitmap->buffer[srow + sp] >= 128 ? COLIDX_FILL : COLIDX_TRANSPARENT;
  } /*paste_bitmap*/

static void add_outline
  (
    unsigned char * image,
    int width, /* dimensions of image */
    int height,
    int stride
  )
  /* puts an outline around the text. */
  {
    int x, y, x1, y1;
    const int maxradius = ceil(subtitle_font_thickness);
    for (y = 0; y < height; ++y)
      {
        for (x = 0; x < width; ++x)
          {
            if (image[y * stride + x] == COLIDX_FILL)
              {
                for
                  (
                    y1 = y >= maxradius ? y - maxradius : 0;
                    y1 < y + maxradius && y1 + maxradius < height;
                    ++y1
                  )
                  {
                    for
                      (
                        x1 = x >= maxradius ? x - maxradius : 0;
                        x1 < x + maxradius && x1 + maxradius < width;
                        ++x1
                      )
                      {
                        if
                          (
                                image[y1 * stride + x1] == COLIDX_TRANSPARENT
                            &&
                                    (y1 - y) * (y1 - y) + (x1 - x) * (x1 - x)
                                <
                                    subtitle_font_thickness * subtitle_font_thickness
                          )
                          {
                            image[y1 * stride + x1] = COLIDX_OUTLINE;
                          } /*if*/
                      } /*for*/
                  } /*for*/
              } /*if*/
          } /*for*/
      } /*for*/
  } /*add_outline*/

static void add_shadow
  (
    unsigned char * image,
    int width, /* dimensions of image */
    int height,
    int stride
  )
  /* adds a shadow to the text. */
  {
    int x, y;
    for
      (
        y = subtitle_shadow_dy < 0 ? -subtitle_shadow_dy : 0;
        y < (subtitle_shadow_dy > 0 ? height - subtitle_shadow_dy : height);
        ++y
      )
      {
        for
          (
            x = subtitle_shadow_dx < 0 ? -subtitle_shadow_dx : 0;
            x < (subtitle_shadow_dx > 0 ? width - subtitle_shadow_dx : width);
            ++x
          )
          {
            const int dstpix = (y + subtitle_shadow_dy) * stride + (x + subtitle_shadow_dx);
            if
              (
                    (
                        image[y * stride + x] == COLIDX_FILL
                    ||
                        image[y * stride + x] == COLIDX_OUTLINE
                    )
                &&
                    image[dstpix] == COLIDX_TRANSPARENT
              )
              {
                image[dstpix] = COLIDX_SHADOW;
              } /*if*/
          } /*for*/
      } /*for*/
  } /*add_shadow*/

void render_one_glyph(font_desc_t *desc, int c)
  /* renders the glyph corresponding to Unicode character code c and saves the
    image in desc, if it is not there already. */
  {
    FT_GlyphSlot slot;
    FT_UInt glyph_index;
    FT_Glyph oglyph;
    FT_BitmapGlyph glyph;
    int width, height, stride, maxw, off;
    unsigned char *bbuffer;
    int pen_xa;
    const int font = desc->font[c];
    raw_file * const pic_b = desc->pic_b[font];
    int error;
//  fprintf(stderr, "render_one_glyph %d\n", c);
    if (desc->width[c] != -1) /* already rendered */
        return;
    if (desc->font[c] == -1) /* can't render without a font face */
        return;
    glyph_index = desc->glyph_index[c];
    // load glyph into the face's glyph slot
    error = FT_Load_Glyph(desc->faces[font], glyph_index, font_load_flags);
    if (error)
      {
        WARNING("FT_Load_Glyph 0x%02x (char 0x%04x) failed.", glyph_index, c);
        desc->font[c] = -1;
        return;
      } /*if*/
    slot = desc->faces[font]->glyph;
    // render glyph
    if (slot->format != FT_GLYPH_FORMAT_BITMAP)
      {
      /* make it a bitmap */
        error = FT_Render_Glyph(slot, FT_RENDER_MODE_NORMAL);
        if (error)
          {
            WARNING("FT_Render_Glyph 0x%04x (char 0x%04x) failed.", glyph_index, c);
            desc->font[c] = -1;
            return;
          } /*if*/
      } /*if*/
    // extract glyph image
    error = FT_Get_Glyph(slot, &oglyph);
    if (error)
      {
        WARNING("FT_Get_Glyph 0x%04x (char 0x%04x) failed.", glyph_index, c);
        desc->font[c] = -1;
        return;
      } /*if*/
    if (oglyph->format != FT_GLYPH_FORMAT_BITMAP)
      {
        WARNING("FT_Get_Glyph did not return a bitmap glyph.");
        desc->font[c] = -1;
        return;
      } /*if*/
    glyph = (FT_BitmapGlyph)oglyph;
//  fprintf(stderr, "glyph generated\n");
    maxw = pic_b->charwidth;
    if (glyph->bitmap.width > maxw)
      {
        fprintf(stderr, "WARN: glyph too wide!\n");
      } /*if*/
    // allocate new memory, if needed
//  fprintf(stderr, "\n%d %d %d\n", pic_b->charwidth, pic_b->charheight, pic_b->current_alloc);
    off =
            pic_b->current_count
        *
            pic_b->charwidth
        *
            pic_b->charheight;
    if (pic_b->current_count == pic_b->current_alloc)
      { /* filled allocated space for bmp blocks, need more */
        const size_t ALLOC_INCR = 32; /* grow in steps of this */
        const int newsize =
                pic_b->charwidth
            *
                pic_b->charheight
            *
                (pic_b->current_alloc + ALLOC_INCR);
        const int increment =
                pic_b->charwidth
            *
                pic_b->charheight
            *
                ALLOC_INCR;
        pic_b->current_alloc += ALLOC_INCR;
    //  fprintf(stderr, "\nns = %d inc = %d\n", newsize, increment);
        pic_b->bmp = realloc(pic_b->bmp, newsize);
      /* initialize newly-added pixels to transparent: */
        memset(pic_b->bmp + off, COLIDX_TRANSPARENT, increment);
      } /*if*/
    bbuffer = pic_b->bmp + off;
    paste_bitmap /* copy glyph into next available space in pic_b->bmp */
      (
        /*bbuffer =*/ bbuffer,
        /*bitmap =*/ &glyph->bitmap,
        /*x =*/ pic_b->padding + glyph->left,
        /*y =*/ pic_b->baseline - glyph->top,
        /*width =*/ pic_b->charwidth,
        /*height =*/ pic_b->charheight,
        /*bwidth =*/ glyph->bitmap.width <= maxw ? glyph->bitmap.width : maxw
      );
//  fprintf(stderr, "glyph pasted\n");
    FT_Done_Glyph((FT_Glyph)glyph);
  /* advance pen */
    pen_xa = f266ToInt(slot->advance.x) + 3 * pic_b->padding;
    if (pen_xa > maxw)
        pen_xa = maxw;
    desc->start[c] = off;
    width = desc->width[c] = pen_xa;
    height = pic_b->charheight;
    stride = pic_b->w;
    add_outline(bbuffer, width, height, stride);
    if (subtitle_shadow_dx != 0 || subtitle_shadow_dy != 0)
      {
        add_shadow(bbuffer, width, height, stride);
      } /*if*/
//  fprintf(stderr, "fg: outline & shadow t = %lf\n", GetTimer()-t);
    pic_b->current_count++;
  } /*render_one_glyph*/

static int check_font
  (
    font_desc_t *desc,
    float ppem,
    int padding, /* extra space to allow between characters */
    int pic_idx, /* which face to select from desc->faces */
    int charset_size, /* length of charset array */
    const FT_ULong *charset /* character codes to get glyphs for */
  )
  /* computes various information about the specified font and puts it into desc. */
  {
    FT_Error error;
    const FT_Face face = desc->faces[pic_idx];
    raw_file * const pic_b = desc->pic_b[pic_idx];
    int ymin = INT_MAX, ymax = INT_MIN;
    int space_advance = 20;
    int width, height;
    int i;
    error = FT_Select_Charmap(face, FT_ENCODING_UNICODE);
//  fprintf(stderr, "select unicode charmap: %d\n", error);
    if (error != 0 || face->charmap == NULL || face->charmap->encoding != FT_ENCODING_UNICODE)
      {
        WARNING("Unicode charmap not available for this font. Very bad!");
      /* fallback to whatever encoding is available */
        error = FT_Set_Charmap(face, face->charmaps[0]);
        if (error)
            WARNING("No charmaps! Strange.");
      } /*if*/
  /* set size */
    if (FT_IS_SCALABLE(face))
      {
        const int horiz_resolution =
            widescreen ?
                54 /* = 72 * (4 / 3) / (16 / 9) */
            :
                72;
        const int vert_resolution =
            default_video_format == VF_NTSC ?
                64 /* = 72 * 480 / 540 */
            : /* default_video_format == VF_PAL ? */
                77; /* = 72 * 576 / 540 */
        error = FT_Set_Char_Size
          (
            /*face =*/ face,
            /*char_width =*/ 0, /* use height */
            /*char_height =*/ floatTof266(ppem),
            /*horiz_resolution =*/ horiz_resolution,
            /*vert_resolution =*/ vert_resolution
          );
        if (error)
            WARNING("FT_Set_Char_Size failed.");
      /* fixme: should I take nonsquare pixels into account in outline
        and shadow rendering as well? */
      }
    else
      {
        int j = 0;
        int jppem = face->available_sizes[0].height;
      /* find closest size */
        for (i = 0; i < face->num_fixed_sizes; ++i)
          {
            if
              (
                    fabs(face->available_sizes[i].height - ppem)
                <
                    abs(face->available_sizes[i].height - jppem)
              )
              {
                j = i;
                jppem = face->available_sizes[i].height;
              } /*if*/
          } /*for*/
        WARNING("Selected font is not scalable. Using ppem=%i.", face->available_sizes[j].height);
        error = FT_Set_Pixel_Sizes
          (
            /*face =*/ face,
            /*pixel_width =*/ face->available_sizes[j].width,
            /*pixel_height =*/ face->available_sizes[j].height
          );
        if (error)
            WARNING("FT_Set_Pixel_Sizes failed.");
      } /*if*/
    if (FT_IS_FIXED_WIDTH(face))
        WARNING("Selected font is fixed-width.");
  /* compute space advance */
    error = FT_Load_Char(face, ' ', font_load_flags);
    if (error)
        WARNING("spacewidth set to default.");
    else
        space_advance = f266ToInt(face->glyph->advance.x);
    if (!desc->spacewidth)
        desc->spacewidth = 2 * padding + space_advance;
    if (!desc->charspace)
        desc->charspace = -2 * padding;
    if (!desc->height)
        desc->height = f266ToInt(face->size->metrics.height);
    for (i = 0; i < charset_size; ++i)
      {
        const FT_ULong character = charset[i];
        FT_UInt glyph_index;
        desc->font[character] = pic_idx;
        // get glyph index
        if (character == 0)
            glyph_index = 0;
        else
          {
            glyph_index = FT_Get_Char_Index(face, character);
            if (glyph_index == 0)
              {
                WARNING("Glyph for char U+%04X|%c not found.",
                    (unsigned int)character,
                    character < ' ' || character > 255 ? '.' : (unsigned int)character);
                desc->font[character] = -1;
                continue;
              } /*if*/
          } /*if*/
        desc->glyph_index[character] = glyph_index;
      } /*for*/
//  fprintf(stderr, "font height: %lf\n", (double)(face->bbox.yMax - face->bbox.yMin) / (double)face->units_per_EM * ppem);
//  fprintf(stderr, "font width: %lf\n", (double)(face->bbox.xMax - face->bbox.xMin)/(double)face - >units_per_EM * ppem);
    ymax = (double)face->bbox.yMax / (double)face->units_per_EM * ppem + 1;
    ymin = (double)face->bbox.yMin / (double)face->units_per_EM * ppem - 1;
    width = ppem * (face->bbox.xMax - face->bbox.xMin) / face->units_per_EM + 3 + 2 * padding;
    if (desc->max_width < width)
        desc->max_width = width;
    width = ALIGN_8BYTES(width);
    pic_b->charwidth = width;
    if (width <= 0)
      {
        fprintf(stderr, "ERR:  Wrong bounding box, width <= 0 !\n");
        return -1;
      } /*if*/
    if (ymax <= ymin)
      {
        fprintf(stderr, "ERR:  Something went wrong. Use the source!\n");
        return -1;
      } /*if*/
    height = ymax - ymin + 2 * padding;
    if (height <= 0)
      {
        fprintf(stderr, "ERR:  Wrong bounding box, height <= 0 !\n");
        return -1;
      } /*if*/
    if (desc->max_height < height)
        desc->max_height = height;
    pic_b->charheight = height;
//  fprintf(stderr, "font height2: %d\n", height);
    pic_b->baseline = ymax + padding;
    pic_b->padding = padding;
    pic_b->current_alloc = 0;
    pic_b->current_count = 0;
    pic_b->w = width;
    pic_b->h = height;
    pic_b->bmp = NULL;
    pic_b->pen = 0;
    return 0;
  } /*check_font*/

static int prepare_font
  (
    font_desc_t *desc,
    FT_Face face,
    float ppem,
    int pic_idx, /* which entry in desc->faces to set up */
    int charset_size, /* length of charset array */
    const FT_ULong *charset, /* character codes to get glyphs for */
    double thickness /* only to compute inter-character padding */
  )
  /* fills in parts of desc indexed by pic_idx with face and related information. */
  {
    int err;
    const int padding = ceil(thickness);
    raw_file * pic_b;
    desc->faces[pic_idx] = face;
    pic_b = (raw_file *)malloc(sizeof(raw_file));
    if (pic_b == NULL)
        return -1;
    desc->pic_b[pic_idx] = pic_b;
    pic_b->bmp = NULL;
    memset(pic_b->pal, 0, sizeof pic_b->pal);
    pic_b->pal[COLIDX_FILL] = subtitle_fill_color;
    pic_b->pal[COLIDX_OUTLINE] = subtitle_outline_color;
    pic_b->pal[COLIDX_SHADOW] = subtitle_shadow_color;
//  ttime = GetTimer();
    err = check_font(desc, ppem, padding, pic_idx, charset_size, charset);
//  ttime = GetTimer() - ttime;
//  printf("render:   %7lf us\n", ttime);
    if (err)
        return -1;
//  fprintf(stderr, "fg: render t = %lf\n", GetTimer() - t);
    pic_b->bmp = NULL;
//  fprintf(stderr, "fg: w = %d, h = %d\n", pic_b->w, pic_b->h);
    return 0;
  } /*prepare_font*/

static int prepare_charset_unicode
  (
    FT_Face face,
    FT_ULong *charset
  )
  /* fills in charset with all the character codes for which glyphs are defined in the font. */
  {
#ifdef HAVE_FREETYPE21
    FT_ULong charcode;
#else
    int j;
#endif
    FT_UInt gindex;
    int i;
    if (face->charmap == NULL || face->charmap->encoding != FT_ENCODING_UNICODE)
      {
        WARNING("Unicode charmap not available for this font. Very bad!");
        return -1;
      } /*if*/
#ifdef HAVE_FREETYPE21
    i = 0;
    charcode = FT_Get_First_Char(face, &gindex);
    while (gindex != 0)
      {
        if (charcode < 65536 && charcode >= 33) // sanity check
          {
            charset[i] = charcode;
            i++;
          } /*if*/
        charcode = FT_Get_Next_Char(face, charcode, &gindex);
      } /*while*/
#else
  // for FT < 2.1 we have to use brute force enumeration
    i = 0;
    for (j = 33; j < 65536; j++)
      {
        gindex = FT_Get_Char_Index(face, j);
        if (gindex > 0)
          {
            charset[i] = j;
            i++;
          } /*if*/
      } /*for*/
#endif
    fprintf(stderr, "INFO: Unicode font: %d glyphs.\n", i);
    return i;
  } /*prepare_charset_unicode*/

static font_desc_t* init_font_desc()
  /* allocates and initializes a new font_desc_t structure. */
  {
    font_desc_t *desc;
    int i;
    desc = malloc(sizeof(font_desc_t));
    if (!desc)
        return NULL;
    memset(desc, 0, sizeof(font_desc_t));
  /* setup sane defaults, mark all associated storage as unallocated */
    desc->face_cnt = 0;
    desc->charspace = 0;
    desc->spacewidth = 0;
    desc->height = 0;
    desc->max_width = 0;
    desc->max_height = 0;
    for (i = 0; i < 65536; i++)
        desc->start[i] = desc->width[i] = desc->font[i] = -1; /* indicate no glyph images cached */
    for (i = 0; i < 16; i++)
        desc->pic_b[i] = NULL;
    return desc;
  } /*init_font_desc*/

static void free_font_desc(font_desc_t *desc)
  /* disposes of all storage allocated for a font_desc_t structure. */
  {
    int i;
    if (!desc)
        return; /* nothing to do */
    for (i = 0; i < 16; i++)
      {
        if (desc->pic_b[i])
          {
            free(desc->pic_b[i]->bmp);
          } /*if*/
        free(desc->pic_b[i]);
      } /*for*/
    for (i = 0; i < desc->face_cnt; i++)
      {
        FT_Done_Face(desc->faces[i]);
      } /*for*/
    free(desc);
  } /*free_font_desc*/

static void load_sub_face(const char *name, FT_Face *face)
  /* loads the font with the specified name and returns it in face. */
  {
    int err = -1;
#if HAVE_FONTCONFIG
    FcPattern *searchpattern, *foundpattern;
    FcResult result = FcResultMatch;
    FcChar8 *foundfilename;
#endif /* HAVE_FONTCONFIG */
#if HAVE_FONTCONFIG
    searchpattern = NULL;
    foundpattern = NULL;
#endif /*HAVE_FONTCONFIG*/
    do /*once*/
      {
      /* fixme: would be good to try interpreting relative path as relative to
        XML control file */
        err = FT_New_Face(library, name, 0, face);
        if (err == 0 || strchr(name, '/') != NULL)
            break;
#if HAVE_FONTCONFIG
        if (strchr(name, '.') != NULL) /* only try this if it looks like a file name */
#endif /*HAVE_FONTCONFIG*/
          {
          /* see if it can be found in config_path */
            const char * const fontpath = get_config_path(name);
            err = FT_New_Face(library, fontpath, 0, face);
            free((void *)fontpath);
            if (err == 0)
                break;
          } /*if*/
#if HAVE_FONTCONFIG
    /* adaptation of patch by Nicolas George: add support for fontconfig. */
        if (!FcInit())
          {
            fprintf(stderr, "ERR:  cannot initialize fontconfig.\n");
            break;
          } /*if*/
        searchpattern = FcNameParse((const FcChar8 *)name);
        if (searchpattern == NULL)
          {
            fprintf(stderr, "ERR:  cannot parse font name.\n");
            break;
          } /*if*/
        if (!FcConfigSubstitute(NULL, searchpattern, FcMatchPattern))
          {
            fprintf(stderr, "ERR:  cannot substitute font configuration.\n");
            break;
          } /*if*/
        FcDefaultSubstitute(searchpattern);
        foundpattern = FcFontMatch(NULL, searchpattern, &result);
        if (foundpattern == NULL || result != FcResultMatch)
          {
            fprintf(stderr, "ERR:  cannot match font name.\n");
            break;
          } /*if*/
        if (FcPatternGetString(foundpattern, FC_FILE, 0, &foundfilename) != FcResultMatch)
          {
            fprintf(stderr, "ERR:  cannot get the font name.\n");
            break;
          } /*if*/
        fprintf(stderr, "INFO: font name \"%s\" matches font file %s\n", name, foundfilename);
        err = FT_New_Face(library, (const char *)foundfilename, 0, face);
        if (err == 0)
            break;
#endif /*HAVE_FONTCONFIG*/
      }
    while (false);
#if HAVE_FONTCONFIG
    if (searchpattern != NULL)
      {
        FcPatternDestroy(searchpattern);
      } /*if*/
    if (foundpattern != NULL)
      {
        FcPatternDestroy(foundpattern);
      } /*if*/
#endif /*HAVE_FONTCONFIG*/
    if (err != 0)
      {
        fprintf
          (
            stderr,
            "ERR:  New_Face failed. Maybe the font path is wrong.\n"
                "ERR:  Please supply the text font file (%s).\n",
            name
          );
        exit(1);
      } /*if*/
  } /*load_sub_face*/

int kerning(font_desc_t *desc, int prevc, int c)
  /* returns the amount of kerning to apply between character c and previous character prevc. */
  {
    FT_Vector kern;
    if (prevc < 0 || c < 0) /* need 2 characters to kern */
        return 0;
    if (desc->font[prevc] != desc->font[c]) /* font change => don't kern */
        return 0;
    if (desc->font[prevc] == -1 /* <=> desc->font[c] == -1 */)
        return 0;
    FT_Get_Kerning
      (
        /*face =*/ desc->faces[desc->font[c]],
        /*left_glyph =*/ desc->glyph_index[prevc],
        /*right_glyph =*/ desc->glyph_index[c],
        /*kern_mode =*/ FT_KERNING_DEFAULT,
        /*akerning =*/ &kern
      );
//  fprintf(stderr, "kern: %c %c %d\n", prevc, c, f266ToInt(kern.x));
    return f266ToInt(kern.x);
  } /*kerning*/

static font_desc_t * read_font_desc_ft
  (
    const char *fname,
    int movie_width,
    int movie_height
  )
  /* returns a font_desc_t structure that can be used to render glyphs with
    the font loaded from the specified file to make subtitles for a movie
    with the specified dimensions. */
  {
    font_desc_t *desc;
    FT_Face face;
    FT_ULong my_charset[MAX_CHARSET_SIZE]; /* characters we want to render; Unicode */
    int err;
    int charset_size;
    int i, j;
    float movie_size;
    float subtitle_font_ppem;
    switch (subtitle_autoscale)
      {
    case AUTOSCALE_MOVIE_HEIGHT:
        movie_size = movie_height;
    break;
    case AUTOSCALE_MOVIE_WIDTH:
        movie_size = movie_width;
    break;
    case AUTOSCALE_MOVIE_DIAGONAL:
        movie_size = sqrt(movie_height * movie_height + movie_width * movie_width);
    break;
    case AUTOSCALE_NONE:
    default:
        movie_size = 100;
    break;
      } /*switch*/
    subtitle_font_ppem = movie_size * text_font_scale_factor / 100.0;
    if (subtitle_font_ppem < 5)
        subtitle_font_ppem = 5; /* try to ensure it stays legible */
    if (subtitle_font_ppem > 128)
        subtitle_font_ppem = 128; /* don't go overboard--why not? */
    desc = init_font_desc();
    if (!desc)
        return NULL;
//  t = GetTimer();
  /* generate the subtitle font */
    load_sub_face(fname, &face);
    desc->face_cnt++; /* will always be 1, since I just created desc */
    charset_size = prepare_charset_unicode(face, my_charset);
    if (charset_size < 0)
      {
        fprintf(stderr, "ERR:  subtitle font: prepare_charset_unicode failed.\n");
        free_font_desc(desc);
        return NULL;
      } /*if*/
//  fprintf(stderr, "fg: prepare t = %lf\n", GetTimer() - t);
    err = prepare_font
      (
        /*desc =*/ desc,
        /*face =*/ face,
        /*ppem =*/ subtitle_font_ppem,
        /*pic_idx =*/ desc->face_cnt - 1,
        /*charset_size =*/ charset_size,
        /*charset =*/ my_charset,
        /*thickness =*/ subtitle_font_thickness
      );
    if (err)
      {
        fprintf(stderr, "ERR:  Cannot prepare subtitle font.\n");
        free_font_desc(desc);
        return NULL;
      } /*if*/
    // final cleanup
    desc->font[' '] = -1;
    desc->width[' '] = desc->spacewidth;
    j = '_';
    if (desc->font[j] < 0)
        j = '?';
    if (desc->font[j] < 0)
        j = ' ';
    render_one_glyph(desc, j);
    for (i = 0; i < 65536; i++)
      {
        if (i != ' ' && desc->font[i] < 0)
          {
            desc->start[i] = desc->start[j];
            desc->width[i] = desc->width[j];
            desc->font[i] = desc->font[j];
          } /*if*/
      } /*for*/
    return desc;
  } /*read_font_desc_ft*/

int init_freetype()
 /* initializes the FreeType library. */
  {
    int err;
    if (!freetype_inited)
      {
      /* initialize freetype */
        err = FT_Init_FreeType(&library);
        if (err)
          {
            fprintf(stderr, "ERR:  Init_FreeType failed.\n");
            return -1;
          } /*if*/
    /*  fprintf(stderr, "INFO: init_freetype\n"); */
        freetype_inited = true;
      } /*if*/
    return 0;
  } /*init_freetype*/

int done_freetype()
  /* called when finished with the FreeType library. */
  {
    int err;
    if (!freetype_inited)
        return 0;
    free_font_desc(vo_font);
    vo_font = NULL;
#if 0 /* don't bother */
    freetype_inited = false;
    err = FT_Done_FreeType(library);
    if (err)
      {
        fprintf(stderr, "ERR:  FT_Done_FreeType failed.\n");
        return -1;
      } /*if*/
#endif
    return 0;
  } /*done_freetype*/

void load_font_ft()
  /* sets up vo_font for rendering glyphs with the font named sub_font to
    make subtitles for a movie with the specified width and height. */
  {
    free_font_desc(vo_font);
    vo_font = read_font_desc_ft(sub_font, movie_width, movie_height);
  } /*load_font_ft*/

#endif /* HAVE_FREETYPE */