pango-utils.c

Pango is a library for layout and rendering of text, with an emphasis on internationalization. Pang

 * @mirrored_ch: location to store the mirrored character
 *
 * If @ch has the Unicode mirrored property and there is another Unicode
 * character that typically has a glyph that is the mirror image of @ch's
 * glyph, puts that character in the address pointed to by @mirrored_ch.
 *
 * Use g_unichar_get_mirror_char() instead; the docs for that function
 * provide full details.
 *
 * Return value: %TRUE if @ch has a mirrored character and @mirrored_ch is
 * filled in, %FALSE otherwise
 **/
gboolean
pango_get_mirror_char (gunichar        ch,
		       gunichar       *mirrored_ch)
{
  return g_unichar_get_mirror_char (ch, mirrored_ch);
}


static guint
alias_hash (struct PangoAlias *alias)
{
  return g_str_hash (alias->alias);
}

static gboolean
alias_equal (struct PangoAlias *alias1,
	     struct PangoAlias *alias2)
{
  return g_str_equal (alias1->alias,
		      alias2->alias);
}


static void
alias_free (struct PangoAlias *alias)
{
  int i;
  g_free (alias->alias);

  for (i = 0; i < alias->n_families; i++)
    g_free (alias->families[i]);

  g_free (alias->families);

  g_slice_free (struct PangoAlias, alias);
}

static void
handle_alias_line (GString  *line_buffer,
		   char    **errstring)
{
  GString *tmp_buffer1;
  GString *tmp_buffer2;
  const char *pos;
  struct PangoAlias alias_key;
  struct PangoAlias *alias;
  gboolean append = FALSE;
  char **new_families;
  int n_new;
  int i;

  tmp_buffer1 = g_string_new (NULL);
  tmp_buffer2 = g_string_new (NULL);


  pos = line_buffer->str;
  if (!pango_skip_space (&pos))
    return;

  if (!pango_scan_string (&pos, tmp_buffer1) ||
      !pango_skip_space (&pos))
    {
      *errstring = g_strdup ("Line is not of the form KEY=VALUE or KEY+=VALUE");
      goto error;
    }

  if (*pos == '+')
    {
      append = TRUE;
      pos++;
    }

  if (*(pos++) != '=')
    {
      *errstring = g_strdup ("Line is not of the form KEY=VALUE or KEY+=VALUE");
      goto error;
    }

  if (!pango_scan_string (&pos, tmp_buffer2))
    {
      *errstring = g_strdup ("Error parsing value string");
      goto error;
    }
  if (pango_skip_space (&pos))
    {
      *errstring = g_strdup ("Junk after value string");
      goto error;
    }

  alias_key.alias = g_ascii_strdown (tmp_buffer1->str, -1);

  /* Remove any existing values */
  alias = g_hash_table_lookup (pango_aliases_ht, &alias_key);

  if (!alias)
    {
      alias = g_slice_new0 (struct PangoAlias);
      alias->alias = alias_key.alias;
      
      g_hash_table_insert (pango_aliases_ht,
			   alias, alias);
    }
  else
    g_free (alias_key.alias);

  new_families = g_strsplit (tmp_buffer2->str, ",", -1);

  n_new = 0;
  while (new_families[n_new])
    n_new++;

  if (alias->families && append)
    {
      alias->families = g_realloc (alias->families,
				   sizeof (char *) *(n_new + alias->n_families));
      for (i = 0; i < n_new; i++)
	alias->families[alias->n_families + i] = new_families[i];
      g_free (new_families);
      alias->n_families += n_new;
    }
  else
    {
      for (i = 0; i < alias->n_families; i++)
	g_free (alias->families[i]);
      g_free (alias->families);
      
      alias->families = new_families;
      alias->n_families = n_new;
    }

 error:
  
  g_string_free (tmp_buffer1, TRUE);
  g_string_free (tmp_buffer2, TRUE);
}

#ifdef G_OS_WIN32

static const char *builtin_aliases[] = {
  "courier = \"courier new\"",
  "\"segoe ui\" = \"segoe ui,arial unicode ms,browallia new,mingliu,simhei,gulimche,ms gothic,sylfaen,kartika,latha,mangal,raavi\"",
  "tahoma = \"tahoma,arial unicode ms,browallia new,mingliu,simhei,gulimche,ms gothic,sylfaen,kartika,latha,mangal,raavi\"",
  /* It sucks to use the same GulimChe, MS Gothic, Sylfaen, Kartika,
   * Latha, Mangal and Raavi fonts for all three of sans, serif and
   * mono, but it isn't like there would be much choice. For most
   * non-Latin scripts that Windows includes any font at all for, it
   * has ony one. One solution is to install the free DejaVu fonts
   * that are popular on Linux. They are listed here first.
   */
  "sans = \"dejavu sans,tahoma,arial unicode ms,browallia new,mingliu,simhei,gulimche,ms gothic,sylfaen,kartika,latha,mangal,raavi\"",
  "sans-serif = \"dejavu sans,tahoma,arial unicode ms,browallia new,mingliu,simhei,gulimche,ms gothic,sylfaen,kartika,latha,mangal,raavi\"",
  "serif = \"dejavu serif,georgia,angsana new,mingliu,simsun,gulimche,ms gothic,sylfaen,kartika,latha,mangal,raavi\"",
  "mono = \"dejavu sans mono,courier new,courier monothai,mingliu,simsun,gulimche,ms gothic,sylfaen,kartika,latha,mangal,raavi\"",
  "monospace = \"dejavu sans mono,courier new,courier monothai,mingliu,simsun,gulimche,ms gothic,sylfaen,kartika,latha,mangal,raavi\""
};

static void
read_builtin_aliases (void)
{

  GString *line_buffer;
  char *errstring = NULL;
  int line;

  line_buffer = g_string_new (NULL);

  for (line = 0; line < G_N_ELEMENTS (builtin_aliases) && errstring == NULL; line++)
    {
      g_string_assign (line_buffer, builtin_aliases[line]);
      handle_alias_line (line_buffer, &errstring);
    }

  if (errstring)
    {
      g_error ("error in built-in aliases:%d: %s\n", line, errstring);
      g_free (errstring);
    }

  g_string_free (line_buffer, TRUE);
}

#endif

static void
read_alias_file (const char *filename)
{
  FILE *file;

  GString *line_buffer;
  char *errstring = NULL;
  int line = 0;

  file = g_fopen (filename, "r");
  if (!file)
    return;

  line_buffer = g_string_new (NULL);

  while (pango_read_line (file, line_buffer) &&
	 errstring == NULL)
    {
      line++;
      handle_alias_line (line_buffer, &errstring);
    }

  if (errstring == NULL && ferror (file))
    errstring = g_strdup (g_strerror(errno));

  if (errstring)
    {
      g_warning ("error reading alias file: %s:%d: %s\n", filename, line, errstring);
      g_free (errstring);
    }

  g_string_free (line_buffer, TRUE);

  fclose (file);
}

static void
pango_load_aliases (void)
{
  char *filename;
  const char *home;

  pango_aliases_ht = g_hash_table_new_full ((GHashFunc)alias_hash,
					    (GEqualFunc)alias_equal,
					    (GDestroyNotify)alias_free,
					    NULL);

#ifdef G_OS_WIN32
  read_builtin_aliases ();
#endif

  filename = g_strconcat (pango_get_sysconf_subdirectory (),
			  G_DIR_SEPARATOR_S "pango.aliases",
			  NULL);
  read_alias_file (filename);
  g_free (filename);

  home = g_get_home_dir ();
  if (home && *home)
    {
      filename = g_strconcat (home,
			      G_DIR_SEPARATOR_S ".pango.aliases",
			      NULL);
      read_alias_file (filename);
      g_free (filename);
    }
}


/**
 * pango_lookup_aliases:
 * @fontname: an ascii string
 * @families: will be set to an array of font family names.
 *    this array is owned by pango and should not be freed.
 * @n_families: will be set to the length of the @families array.
 *
 * Look up all user defined aliases for the alias @fontname.
 * The resulting font family names will be stored in @families,
 * and the number of families in @n_families.
 **/
void
pango_lookup_aliases (const char   *fontname,
		      char       ***families,
		      int          *n_families)
{
  struct PangoAlias alias_key;
  struct PangoAlias *alias;

  if (pango_aliases_ht == NULL)
    pango_load_aliases ();

  alias_key.alias = g_ascii_strdown (fontname, -1);
  alias = g_hash_table_lookup (pango_aliases_ht, &alias_key);
  g_free (alias_key.alias);

  if (alias)
    {
      *families = alias->families;
      *n_families = alias->n_families;
    }
  else
    {
      *families = NULL;
      *n_families = 0;
    }
}

/**
 * pango_find_base_dir:
 * @text:   the text to process
 * @length: length of @text in bytes (may be -1 if @text is nul-terminated)
 *
 * Searches a string the first character that has a strong
 * direction, according to the Unicode bidirectional algorithm.
 *
 * Return value: The direction corresponding to the first strong character.
 * If no such character is found, then %PANGO_DIRECTION_NEUTRAL is returned.
 *
 * Since: 1.4
 */
PangoDirection
pango_find_base_dir (const gchar *text,
		     gint         length)
{
  PangoDirection dir = PANGO_DIRECTION_NEUTRAL;
  const gchar *p;

  g_return_val_if_fail (text != NULL || length == 0, PANGO_DIRECTION_NEUTRAL);

  p = text;
  while ((length < 0 || p < text + length) && *p)
    {
      gunichar wc = g_utf8_get_char (p);

      dir = pango_unichar_direction (wc);

      if (dir != PANGO_DIRECTION_NEUTRAL)
	break;

      p = g_utf8_next_char (p);
    }

  return dir;
}

/**
 * pango_is_zero_width:
 * @ch: a Unicode character
 *
 * Checks @ch to see if it is a character that should not be
 * normally rendered on the screen.  This includes all Unicode characters
 * with "ZERO WIDTH" in their name, as well as <firstterm>bidi</firstterm> formatting characters, and
 * a few other ones.  This is totally different from g_unichar_iszerowidth()
 * and is at best misnamed.
 *
 * Return value: %TRUE if @ch is a zero-width character, %FALSE otherwise
 *
 * Since: 1.10
 */
gboolean
pango_is_zero_width (gunichar ch)
{
/* Zero Width characters:
 *
 *  00AD  SOFT HYPHEN
 *  034F  COMBINING GRAPHEME JOINER
 *
 *  200B  ZERO WIDTH SPACE
 *  200C  ZERO WIDTH NON-JOINER
 *  200D  ZERO WIDTH JOINER
 *  200E  LEFT-TO-RIGHT MARK
 *  200F  RIGHT-TO-LEFT MARK
 *
 *  2028  LINE SEPARATOR
 *
 *  202A  LEFT-TO-RIGHT EMBEDDING
 *  202B  RIGHT-TO-LEFT EMBEDDING
 *  202C  POP DIRECTIONAL FORMATTING
 *  202D  LEFT-TO-RIGHT OVERRIDE
 *  202E  RIGHT-TO-LEFT OVERRIDE
 *
 *  2060  WORD JOINER
 *  2061  FUNCTION APPLICATION
 *  2062  INVISIBLE TIMES
 *  2063  INVISIBLE SEPARATOR
 *
 *  FEFF  ZERO WIDTH NO-BREAK SPACE
 */
  return ((ch & ~(gunichar)0x007F) == 0x2000 && (
		(ch >= 0x200B && ch <= 0x200F) ||
		(ch >= 0x202A && ch <= 0x202E) ||
		(ch >= 0x2060 && ch <= 0x2063) ||
		(ch == 0x2028)
	 )) || G_UNLIKELY (ch == 0x00AD
			|| ch == 0x034F
			|| ch == 0xFEFF);
}

/**
 * pango_quantize_line_geometry:
 * @thickness: pointer to the thickness of a line, in Pango units
 * @position: corresponding position
 *
 * Quantizes the thickness and position of a line, typically an
 * underline or strikethrough, to whole device pixels, that is integer
 * multiples of %PANGO_SCALE. The purpose of this function is to avoid
 * such lines looking blurry.
 *
 * Care is taken to make sure @thickness is at least one pixel when this
 * function returns, but returned @position may become zero as a result
 * of rounding.
 *
 * Since: 1.12
 */
void
pango_quantize_line_geometry (int *thickness,
			      int *position)
{
  int thickness_pixels = (*thickness + PANGO_SCALE / 2) / PANGO_SCALE;
  if (thickness_pixels == 0)
    thickness_pixels = 1;

  if (thickness_pixels & 1)
    {
      int new_center = ((*position - *thickness / 2) & ~(PANGO_SCALE - 1)) + PANGO_SCALE / 2;
      *position = new_center + (PANGO_SCALE * thickness_pixels) / 2;
    }
  else
    {
      int new_center = ((*position - *thickness / 2 + PANGO_SCALE / 2) & ~(PANGO_SCALE - 1));
      *position = new_center + (PANGO_SCALE * thickness_pixels) / 2;
    }

  *thickness = thickness_pixels * PANGO_SCALE;
}

/**
 * pango_units_from_double:
 * @d: double floating-point value
 *
 * Converts a floating-point number to Pango units: multiplies
 * it by %PANGO_SCALE and rounds to nearest integer.
 *
 * Return value: the value in Pango units.
 *
 * Since: 1.16
 */
int
pango_units_from_double (double d)
{
  return (int)floor (d * PANGO_SCALE + 0.5);
}

/**
 * pango_units_to_double:
 * @i: value in Pango units
 *
 * Converts a number in Pango units to floating-point: divides
 * it by %PANGO_SCALE.
 *
 * Return value: the double value.
 *
 * Since: 1.16
 */
double
pango_units_to_double (int i)
{
  return (double)i / PANGO_SCALE;
}

/**
 * pango_extents_to_pixels:
 * @inclusive: rectangle to round to pixels inclusively, or %NULL.
 * @nearest: rectangle to round to nearest pixels, or %NULL.
 *
 * Converts extents from Pango units to device units, dividing by the
 * %PANGO_SCALE factor and performing rounding.
 *
 * The @inclusive rectangle is converted by flooring the x/y coordinates and extending
 * width/height, such that the final rectangle completely includes the original
 * rectangle.
 *
 * The @nearest rectangle is converted by rounding the coordinates
 * of the rectangle to the nearest device unit (pixel).
 *
 * The rule to which argument to use is: if you want the resulting device-space
 * rectangle to completely contain the original rectangle, pass it in as @inclusive.
 * If you want two touching-but-not-overlapping rectangles stay
 * touching-but-not-overlapping after rounding to device units, pass them in
 * as @nearest.
 *
 * Since: 1.16
 **/
void
pango_extents_to_pixels (PangoRectangle *inclusive,
			 PangoRectangle *nearest)
{
  if (inclusive)
    {
      int orig_x = inclusive->x;
      int orig_y = inclusive->y;

      inclusive->x = PANGO_PIXELS_FLOOR (inclusive->x);
      inclusive->y = PANGO_PIXELS_FLOOR (inclusive->y);

      inclusive->width  = PANGO_PIXELS_CEIL (orig_x + inclusive->width ) - inclusive->x;
      inclusive->height = PANGO_PIXELS_CEIL (orig_y + inclusive->height) - inclusive->y;
    }

  if (nearest)
    {
      int orig_x = nearest->x;
      int orig_y = nearest->y;

      nearest->x = PANGO_PIXELS (nearest->x);
      nearest->y = PANGO_PIXELS (nearest->y);

      nearest->width  = PANGO_PIXELS (orig_x + nearest->width ) - nearest->x;
      nearest->height = PANGO_PIXELS (orig_y + nearest->height) - nearest->y;
    }
}





/*********************************************************
 * Some internal functions for handling PANGO_ATTR_SHAPE *
 ********************************************************/

void
_pango_shape_shape (const char       *text,
		    gint              n_chars,
		    PangoRectangle   *shape_ink,
		    PangoRectangle   *shape_logical,
		    PangoGlyphString *glyphs)
{
  int i;
  const char *p;

  pango_glyph_string_set_size (glyphs, n_chars);

  for (i=0, p = text; i < n_chars; i++, p = g_utf8_next_char (p))
    {
      glyphs->glyphs[i].glyph = PANGO_GLYPH_EMPTY;
      glyphs->glyphs[i].geometry.x_offset = 0;
      glyphs->glyphs[i].geometry.y_offset = 0;
      glyphs->glyphs[i].geometry.width = shape_logical->width;
      glyphs->glyphs[i].attr.is_cluster_start = 1;

      glyphs->log_clusters[i] = p - text;
    }
}

void
_pango_shape_get_extents (gint              n_chars,
			  PangoRectangle   *shape_ink,
			  PangoRectangle   *shape_logical,
			  PangoRectangle   *ink_rect,
			  PangoRectangle   *logical_rect)
{
  if (n_chars > 0)
    {
      if (ink_rect)
	{
	  ink_rect->x = MIN (shape_ink->x, shape_ink->x + shape_logical->width * (n_chars - 1));
	  ink_rect->width = MAX (shape_ink->width, shape_ink->width + shape_logical->width * (n_chars - 1));
	  ink_rect->y = shape_ink->y;
	  ink_rect->height = shape_ink->height;
	}
      if (logical_rect)
	{
	  logical_rect->x = MIN (shape_logical->x, shape_logical->x + shape_logical->width * (n_chars - 1));
	  logical_rect->width = MAX (shape_logical->width, shape_logical->width + shape_logical->width * (n_chars - 1));
	  logical_rect->y = shape_logical->y;
	  logical_rect->height = shape_logical->height;
	}
    }
  else
    {
      if (ink_rect)
	{
	  ink_rect->x = 0;
	  ink_rect->y = 0;
	  ink_rect->width = 0;
	  ink_rect->height = 0;
	}

      if (logical_rect)
	{
	  logical_rect->x = 0;
	  logical_rect->y = 0;
	  logical_rect->width = 0;
	  logical_rect->height = 0;
	}
    }
}