fonts.c

GTK+-2.0源码之pango-1.15.6.tar.gz

  FIELD (style,   PANGO_FONT_MASK_STYLE);
  FIELD (variant, PANGO_FONT_MASK_VARIANT);
  FIELD (weight,  PANGO_FONT_MASK_WEIGHT);
  FIELD (stretch, PANGO_FONT_MASK_STRETCH);
  FIELD (gravity, PANGO_FONT_MASK_GRAVITY);

#undef FIELD

  return found;
}

static const char *
getword (const char *str, const char *last, size_t *wordlen)
{
  const char *result;

  while (last > str && g_ascii_isspace (*(last - 1)))
    last--;

  result = last;
  while (result > str && !g_ascii_isspace (*(result - 1)))
    result--;

  *wordlen = last - result;

  return result;
}

static gboolean
parse_size (const char *word,
	    size_t      wordlen,
	    int        *pango_size,
	    gboolean   *size_is_absolute)
{
  char *end;
  double size = g_ascii_strtod (word, &end);

  if (end != word &&
      (end == word + wordlen ||
       (end + 2 == word + wordlen && !strncmp (end, "px", 2))
      ) && size >= 0 && size <= 1000000) /* word is a valid float */
    {
      if (pango_size)
	*pango_size = (int)(size * PANGO_SCALE + 0.5);

      if (size_is_absolute)
	*size_is_absolute = end < word + wordlen;

      return TRUE;
    }

  return FALSE;
}

/**
 * pango_font_description_from_string:
 * @str: string representation of a font description.
 *
 * Creates a new font description from a string representation in the
 * form "[FAMILY-LIST] [STYLE-OPTIONS] [SIZE]", where FAMILY-LIST is a
 * comma separated list of families optionally terminated by a comma,
 * STYLE_OPTIONS is a whitespace separated list of words where each WORD
 * describes one of style, variant, weight, stretch, or gravity, and SIZE
 * is a decimal number (size in points) or optionally followed by the
 * unit modifier "px" for absolute size. Any one of the options may
 * be absent.  If FAMILY-LIST is absent, then the family_name field of
 * the resulting font description will be initialized to %NULL.  If
 * STYLE-OPTIONS is missing, then all style options will be set to the
 * default values. If SIZE is missing, the size in the resulting font
 * description will be set to 0.
 *
 * Return value: a new #PangoFontDescription.
 **/
PangoFontDescription *
pango_font_description_from_string (const char *str)
{
  PangoFontDescription *desc;
  const char *p, *last;
  size_t len, wordlen;

  g_return_val_if_fail (str != NULL, NULL);

  desc = pango_font_description_new ();

  desc->mask = PANGO_FONT_MASK_STYLE |
	       PANGO_FONT_MASK_WEIGHT |
	       PANGO_FONT_MASK_VARIANT |
	       PANGO_FONT_MASK_STRETCH;

  len = strlen (str);
  last = str + len;
  p = getword (str, last, &wordlen);

  /* Look for a size at the end of the string
   */
  if (wordlen != 0)
    {
      gboolean size_is_absolute;
      if (parse_size (p, wordlen, &desc->size, &size_is_absolute))
	{
	  desc->size_is_absolute = size_is_absolute;
	  desc->mask |= PANGO_FONT_MASK_SIZE;
	  last = p;
	}
    }

  /* Now parse style words
   */
  p = getword (str, last, &wordlen);
  while (wordlen != 0)
    {
      if (!find_field_any (p, wordlen, desc))
	break;
      else
	{
	  last = p;
	  p = getword (str, last, &wordlen);
	}
    }

  /* Remainder (str => p) is family list. Trim off trailing commas and leading and trailing white space
   */

  while (last > str && g_ascii_isspace (*(last - 1)))
    last--;

  if (last > str && *(last - 1) == ',')
    last--;

  while (last > str && g_ascii_isspace (*(last - 1)))
    last--;

  while (last > str && g_ascii_isspace (*str))
    str++;

  if (str != last)
    {
      desc->family_name = g_strndup (str, last - str);
      desc->mask |= PANGO_FONT_MASK_FAMILY;
    }

  return desc;
}

static void
append_field (GString *str, const FieldMap *map, int n_elements, int val)
{
  int i;
  for (i=0; i<n_elements; i++)
    {
      if (map[i].value == val)
	{
	  if (map[i].str && map[i].str[0])
	    {
	      if (str->len > 0 && str->str[str->len -1] != ' ')
		g_string_append_c (str, ' ');
	      g_string_append (str, map[i].str);
	    }
	  return;
	}
    }

  if (str->len > 0 || str->str[str->len -1] != ' ')
    g_string_append_c (str, ' ');
  g_string_append_printf (str, "%d", val);
}

/**
 * pango_font_description_to_string:
 * @desc: a #PangoFontDescription
 *
 * Creates a string representation of a font description. See
 * pango_font_description_from_string() for a description of the
 * format of the string representation. The family list in the
 * string description will only have a terminating comma if the
 * last word of the list is a valid style option.
 *
 * Return value: a new string that must be freed with g_free().
 **/
char *
pango_font_description_to_string (const PangoFontDescription  *desc)
{
  GString *result = g_string_new (NULL);

  if (desc->family_name && desc->mask & PANGO_FONT_MASK_FAMILY)
    {
      const char *p;
      size_t wordlen;

      g_string_append (result, desc->family_name);

      /* We need to add a trailing comma if the family name ends
       * in a keyword like "Bold", or if the family name ends in
       * a number and no keywords will be added.
       */
      p = getword (desc->family_name, desc->family_name + strlen(desc->family_name), &wordlen);
      if (wordlen != 0 &&
	  (find_field_any (p, wordlen, NULL) ||
	   (parse_size (p, wordlen, NULL, NULL) &&
	    desc->weight == PANGO_WEIGHT_NORMAL &&
	    desc->style == PANGO_STYLE_NORMAL &&
	    desc->stretch == PANGO_STRETCH_NORMAL &&
	    desc->variant == PANGO_VARIANT_NORMAL &&
	    (desc->mask & (PANGO_FONT_MASK_GRAVITY | PANGO_FONT_MASK_SIZE)) == 0)))
	g_string_append_c (result, ',');
    }

  append_field (result, weight_map, G_N_ELEMENTS (weight_map), desc->weight);
  append_field (result, style_map, G_N_ELEMENTS (style_map), desc->style);
  append_field (result, stretch_map, G_N_ELEMENTS (stretch_map), desc->stretch);
  append_field (result, variant_map, G_N_ELEMENTS (variant_map), desc->variant);
  if (desc->mask & PANGO_FONT_MASK_GRAVITY)
    append_field (result, gravity_map, G_N_ELEMENTS (gravity_map), desc->gravity);

  if (result->len == 0)
    g_string_append (result, "Normal");

  if (desc->mask & PANGO_FONT_MASK_SIZE)
    {
      char buf[G_ASCII_DTOSTR_BUF_SIZE];

      if (result->len > 0 || result->str[result->len -1] != ' ')
	g_string_append_c (result, ' ');

      g_ascii_dtostr (buf, sizeof (buf), (double)desc->size / PANGO_SCALE);
      g_string_append (result, buf);

      if (desc->size_is_absolute)
	g_string_append (result, "px");
    }

  return g_string_free (result, FALSE);
}

/**
 * pango_font_description_to_filename:
 * @desc: a #PangoFontDescription
 *
 * Creates a filename representation of a font description. The
 * filename is identical to the result from calling
 * pango_font_description_to_string(), but with underscores instead of
 * characters that are untypical in filenames, and in lower case only.
 *
 * Return value: a new string that must be freed with g_free().
 **/
char *
pango_font_description_to_filename (const PangoFontDescription  *desc)
{
  char *result = pango_font_description_to_string (desc);
  char *p;

  p = result;
  while (*p)
    {
      if (strchr ("-+_.", *p) == NULL && !g_ascii_isalnum (*p))
	*p = '_';
      else
	*p = g_ascii_tolower (*p);
      p++;
    }

  return result;
}

G_DEFINE_TYPE (PangoFont, pango_font, G_TYPE_OBJECT)

static void
pango_font_class_init (PangoFontClass *class)
{
}

static void
pango_font_init (PangoFont *font)
{
}

/**
 * pango_font_describe:
 * @font: a #PangoFont
 *
 * Returns a description of the font, with font size set in points.
 * Use pango_font_describe_with_absolute_size() if you want the font
 * size in device units.
 *
 * Return value: a newly-allocated #PangoFontDescription object.
 **/
PangoFontDescription *
pango_font_describe (PangoFont      *font)
{
  g_return_val_if_fail (font != NULL, NULL);

  return PANGO_FONT_GET_CLASS (font)->describe (font);
}

/**
 * pango_font_describe_with_absolute_size:
 * @font: a #PangoFont
 *
 * Returns a description of the font, with absolute font size set
 * (in device units). Use pango_font_describe() if you want the font
 * size in points.
 *
 * Return value: a newly-allocated #PangoFontDescription object.
 *
 * Since: 1.14
 **/
PangoFontDescription *
pango_font_describe_with_absolute_size (PangoFont      *font)
{
  g_return_val_if_fail (font != NULL, NULL);

  if (G_UNLIKELY (!PANGO_FONT_GET_CLASS (font)->describe_absolute))
    {
      g_warning ("describe_absolute not implemented for this font class, report this as a bug");
      return pango_font_describe (font);
    }

  return PANGO_FONT_GET_CLASS (font)->describe_absolute (font);
}

/**
 * pango_font_get_coverage:
 * @font: a #PangoFont
 * @language: the language tag
 *
 * Computes the coverage map for a given font and language tag.
 *
 * Return value: a newly-allocated #PangoCoverage object.
 **/
PangoCoverage *
pango_font_get_coverage (PangoFont     *font,
			 PangoLanguage *language)
{
  g_return_val_if_fail (font != NULL, NULL);

  return PANGO_FONT_GET_CLASS (font)->get_coverage (font, language);
}

/**
 * pango_font_find_shaper:
 * @font: a #PangoFont
 * @language: the language tag
 * @ch: a Unicode character.
 *
 * Finds the best matching shaper for a font for a particular
 * language tag and character point.
 *
 * Return value: the best matching shaper.
 **/
PangoEngineShape *
pango_font_find_shaper (PangoFont     *font,
			PangoLanguage *language,
			guint32        ch)
{
  PangoEngineShape* shaper;

  g_return_val_if_fail (font != NULL, NULL);

  shaper = PANGO_FONT_GET_CLASS (font)->find_shaper (font, language, ch);

  return shaper;
}

/**
 * pango_font_get_glyph_extents:
 * @font: a #PangoFont
 * @glyph: the glyph index
 * @ink_rect: rectangle used to store the extents of the glyph as drawn
 *            or %NULL to indicate that the result is not needed.
 * @logical_rect: rectangle used to store the logical extents of the glyph
 *            or %NULL to indicate that the result is not needed.
 *
 * Gets the logical and ink extents of a glyph within a font. The
 * coordinate system for each rectangle has its origin at the
 * base line and horizontal origin of the character with increasing
 * coordinates extending to the right and down. The macros PANGO_ASCENT(),
 * PANGO_DESCENT(), PANGO_LBEARING(), and PANGO_RBEARING() can be used to convert
 * from the extents rectangle to more traditional font metrics. The units
 * of the rectangles are in 1/PANGO_SCALE of a device unit.
 **/
void
pango_font_get_glyph_extents  (PangoFont      *font,
			       PangoGlyph      glyph,
			       PangoRectangle *ink_rect,
			       PangoRectangle *logical_rect)
{
  if (G_UNLIKELY (!font))
    {

      if (!_pango_warning_history.get_glyph_extents)
	{
	  _pango_warning_history.get_glyph_extents = TRUE;
	  g_warning (bad_font_warning, "pango_font_get_glyph_extents");
	}
      if (ink_rect)
	{
	  ink_rect->x = PANGO_SCALE;
	  ink_rect->y = - (PANGO_UNKNOWN_GLYPH_HEIGHT - 1) * PANGO_SCALE;
	  ink_rect->height = (PANGO_UNKNOWN_GLYPH_HEIGHT - 2) * PANGO_SCALE;
	  ink_rect->width = (PANGO_UNKNOWN_GLYPH_WIDTH - 2) * PANGO_SCALE;
	}
      if (logical_rect)
	{
	  logical_rect->x = logical_rect->y = 0;
	  logical_rect->y = - PANGO_UNKNOWN_GLYPH_HEIGHT * PANGO_SCALE;
	  logical_rect->height = PANGO_UNKNOWN_GLYPH_HEIGHT * PANGO_SCALE;
	  logical_rect->width = PANGO_UNKNOWN_GLYPH_WIDTH * PANGO_SCALE;
	}
      return;
    }

  PANGO_FONT_GET_CLASS (font)->get_glyph_extents (font, glyph, ink_rect, logical_rect);
}

/**
 * pango_font_get_metrics:
 * @font: a #PangoFont
 * @language: language tag used to determine which script to get the metrics
 *            for, or %NULL to indicate to get the metrics for the entire
 *            font.
 *
 * Gets overall metric information for a font. Since the metrics may be
 * substantially different for different scripts, a language tag can
 * be provided to indicate that the metrics should be retrieved that
 * correspond to the script(s) used by that language.
 *
 * Return value: a #PangoFontMetrics object. The caller must call pango_font_metrics_unref()
 *   when finished using the object.
 **/
PangoFontMetrics *
pango_font_get_metrics (PangoFont        *font,
			PangoLanguage    *language)
{
  if (G_UNLIKELY (!font))
    {
      PangoFontMetrics *metrics;

      if (!_pango_warning_history.get_metrics)
	{
	  _pango_warning_history.get_metrics = TRUE;
	  g_warning (bad_font_warning, "pango_font_get_metrics");
	}
      metrics = pango_font_metrics_new ();

      metrics->ascent = PANGO_SCALE * PANGO_UNKNOWN_GLYPH_HEIGHT;
      metrics->descent = 0;
      metrics->approximate_char_width = PANGO_SCALE * PANGO_UNKNOWN_GLYPH_WIDTH;
      metrics->approximate_digit_width = PANGO_SCALE * PANGO_UNKNOWN_GLYPH_WIDTH;
      metrics->underline_position = -PANGO_SCALE;
      metrics->underline_thickness = PANGO_SCALE;
      metrics->strikethrough_position = PANGO_SCALE * PANGO_UNKNOWN_GLYPH_HEIGHT / 2;