fonts.c

GTK+-2.0源码之pango-1.15.6.tar.gz

  desc->gravity = gravity;
  desc->mask |= PANGO_FONT_MASK_GRAVITY;
}

/**
 * pango_font_description_get_gravity:
 * @desc: a #PangoFontDescription
 *
 * Gets the gravity field of a font description. See
 * pango_font_description_set_gravity().
 *
 * Return value: the gravity field for the font description. Use
 *   pango_font_description_get_set_fields() to find out if
 *   the field was explicitly set or not.
 *
 * Since: 1.16
 **/
PangoGravity
pango_font_description_get_gravity (const PangoFontDescription *desc)
{
  g_return_val_if_fail (desc != NULL, pfd_defaults.gravity);

  return desc->gravity;
}

/**
 * pango_font_description_get_set_fields:
 * @desc: a #PangoFontDescription
 *
 * Determines which fields in a font description have been set.
 *
 * Return value: a bitmask with bits set corresponding to the
 *   fields in @desc that have been set.
 **/
PangoFontMask
pango_font_description_get_set_fields (const PangoFontDescription *desc)
{
  g_return_val_if_fail (desc != NULL, pfd_defaults.mask);

  return desc->mask;
}

/**
 * pango_font_description_unset_fields:
 * @desc: a #PangoFontDescription
 * @to_unset: bitmask of fields in the @desc to unset.
 *
 * Unsets some of the fields in a #PangoFontDescription.  The unset
 * fields will get back to their default values.
 **/
void
pango_font_description_unset_fields (PangoFontDescription *desc,
				     PangoFontMask         to_unset)
{
  PangoFontDescription unset_desc;

  g_return_if_fail (desc != NULL);

  unset_desc = pfd_defaults;
  unset_desc.mask = to_unset;

  pango_font_description_merge_static (desc, &unset_desc, TRUE);

  desc->mask &= ~to_unset;
}

/**
 * pango_font_description_merge:
 * @desc: a #PangoFontDescription
 * @desc_to_merge: the #PangoFontDescription to merge from
 * @replace_existing: if %TRUE, replace fields in @desc with the
 *   corresponding values from @desc_to_merge, even if they
 *   are already exist.
 *
 * Merges the fields that are set in @desc_to_merge into the fields in
 * @desc.  If @replace_existing is %FALSE, only fields in @desc that
 * are not already set are affected. If %TRUE, then fields that are
 * already set will be replaced as well.
 **/
void
pango_font_description_merge (PangoFontDescription       *desc,
			      const PangoFontDescription *desc_to_merge,
			      gboolean                    replace_existing)
{
  gboolean family_merged = desc_to_merge->family_name && (replace_existing || !desc->family_name);

  pango_font_description_merge_static (desc, desc_to_merge, replace_existing);

  if (family_merged)
    {
      desc->family_name = g_strdup (desc->family_name);
      desc->static_family = FALSE;
    }
}

/**
 * pango_font_description_merge_static:
 * @desc: a #PangoFontDescription
 * @desc_to_merge: the #PangoFontDescription to merge from
 * @replace_existing: if %TRUE, replace fields in @desc with the
 *   corresponding values from @desc_to_merge, even if they
 *   are already exist.
 *
 * Like pango_font_description_merge(), but only a shallow copy is made
 * of the family name and other allocated fields. @desc can only be
 * used until @desc_to_merge is modified or freed. This is meant
 * to be used when the merged font description is only needed temporarily.
 **/
void
pango_font_description_merge_static (PangoFontDescription       *desc,
				     const PangoFontDescription *desc_to_merge,
				     gboolean                    replace_existing)
{
  PangoFontMask new_mask;

  g_return_if_fail (desc != NULL);

  if (replace_existing)
    new_mask = desc_to_merge->mask;
  else
    new_mask = desc_to_merge->mask & ~desc->mask;

  if (new_mask & PANGO_FONT_MASK_FAMILY)
    pango_font_description_set_family_static (desc, desc_to_merge->family_name);
  if (new_mask & PANGO_FONT_MASK_STYLE)
    desc->style = desc_to_merge->style;
  if (new_mask & PANGO_FONT_MASK_VARIANT)
    desc->variant = desc_to_merge->variant;
  if (new_mask & PANGO_FONT_MASK_WEIGHT)
    desc->weight = desc_to_merge->weight;
  if (new_mask & PANGO_FONT_MASK_STRETCH)
    desc->stretch = desc_to_merge->stretch;
  if (new_mask & PANGO_FONT_MASK_SIZE)
    {
      desc->size = desc_to_merge->size;
      desc->size_is_absolute = desc_to_merge->size_is_absolute;
    }
  if (new_mask & PANGO_FONT_MASK_GRAVITY)
    desc->gravity = desc_to_merge->gravity;

  desc->mask |= new_mask;
}

static gint
compute_distance (const PangoFontDescription *a,
		  const PangoFontDescription *b)
{
  if (a->style == b->style)
    {
      return abs(a->weight - b->weight);
    }
  else if (a->style != PANGO_STYLE_NORMAL &&
	   b->style != PANGO_STYLE_NORMAL)
    {
      /* Equate oblique and italic, but with a big penalty
       */
      return 1000000 + abs (a->weight - b->weight);
    }
  else
    return G_MAXINT;
}

/**
 * pango_font_description_better_match:
 * @desc: a #PangoFontDescription
 * @old_match: a #PangoFontDescription, or %NULL
 * @new_match: a #PangoFontDescription
 *
 * Determines if the style attributes of @new_match are a closer match
 * for @desc than @old_match, or if @old_match is %NULL, determines if
 * @new_match is a match at all. Approximate matching is done for
 * weight and style; other attributes must match exactly.
 *
 * Return value: %TRUE if @new_match is a better match
 **/
gboolean
pango_font_description_better_match (const PangoFontDescription *desc,
				     const PangoFontDescription *old_match,
				     const PangoFontDescription *new_match)
{
  g_return_val_if_fail (desc != NULL, G_MAXINT);
  g_return_val_if_fail (new_match != NULL, G_MAXINT);

  if (new_match->variant == desc->variant &&
      new_match->stretch == desc->stretch &&
      new_match->gravity == desc->gravity)
    {
      int old_distance = old_match ? compute_distance (desc, old_match) : G_MAXINT;
      int new_distance = compute_distance (desc, new_match);

      if (new_distance < old_distance)
	return TRUE;
    }

  return FALSE;
}

/**
 * pango_font_description_copy:
 * @desc: a #PangoFontDescription
 *
 * Make a copy of a #PangoFontDescription.
 *
 * Return value: the newly allocated #PangoFontDescription, which should
 *               be freed with pango_font_description_free().
 **/
PangoFontDescription *
pango_font_description_copy  (const PangoFontDescription  *desc)
{
  PangoFontDescription *result = g_slice_new (PangoFontDescription);

  *result = *desc;

  if (result->family_name)
    {
      result->family_name = g_strdup (result->family_name);
      result->static_family = FALSE;
    }

  return result;
}

/**
 * pango_font_description_copy_static:
 * @desc: a #PangoFontDescription
 *
 * Like pango_font_description_copy(), but only a shallow copy is made
 * of the family name and other allocated fields. The result can only
 * be used until @desc is modified or freed. This is meant to be used
 * when the copy is only needed temporarily.
 *
 * Return value: the newly allocated #PangoFontDescription, which should
 *               be freed with pango_font_description_free().
 **/
PangoFontDescription *
pango_font_description_copy_static (const PangoFontDescription *desc)
{
  PangoFontDescription *result = g_slice_new (PangoFontDescription);

  *result = *desc;
  if (result->family_name)
    result->static_family = TRUE;

  return result;
}

/**
 * pango_font_description_equal:
 * @desc1: a #PangoFontDescription
 * @desc2: another #PangoFontDescription
 *
 * Compares two font descriptions for equality. Two font descriptions
 * are considered equal if the fonts they describe are provably identical.
 * This means that their masks do not have to match, as long as other fields
 * are all the same. (Two font descriptions may result in identical fonts
 * being loaded, but still compare %FALSE.)
 *
 * Return value: %TRUE if the two font descriptions are identical,
 *		 %FALSE otherwise.
 **/
gboolean
pango_font_description_equal (const PangoFontDescription  *desc1,
			      const PangoFontDescription  *desc2)
{
  g_return_val_if_fail (desc1 != NULL, FALSE);
  g_return_val_if_fail (desc2 != NULL, FALSE);

  return desc1->style == desc2->style &&
	 desc1->variant == desc2->variant &&
	 desc1->weight == desc2->weight &&
	 desc1->stretch == desc2->stretch &&
	 desc1->size == desc2->size &&
	 desc1->size_is_absolute == desc2->size_is_absolute &&
	 desc1->gravity == desc2->gravity &&
	 (desc1->family_name == desc2->family_name ||
	  (desc1->family_name && desc2->family_name && g_ascii_strcasecmp (desc1->family_name, desc2->family_name) == 0));
}

#define TOLOWER(c) \
  (((c) >= 'A' && (c) <= 'Z') ? (c) - 'A' + 'a' : (c))

static guint
case_insensitive_hash (const char *key)
{
  const char *p = key;
  guint h = TOLOWER (*p);

  if (h)
    {
      for (p += 1; *p != '\0'; p++)
	h = (h << 5) - h + TOLOWER (*p);
    }

  return h;
}

/**
 * pango_font_description_hash:
 * @desc: a #PangoFontDescription
 *
 * Computes a hash of a #PangoFontDescription structure suitable
 * to be used, for example, as an argument to g_hash_table_new().
 * The hash value is independent of @desc->mask.
 *
 * Return value: the hash value.
 **/
guint
pango_font_description_hash (const PangoFontDescription *desc)
{
  guint hash = 0;

  if (desc->family_name)
    hash = case_insensitive_hash (desc->family_name);
  hash ^= desc->size;
  hash ^= desc->size_is_absolute ? 0xc33ca55a : 0;
  hash ^= desc->style << 16;
  hash ^= desc->variant << 18;
  hash ^= desc->weight << 16;
  hash ^= desc->stretch << 26;
  hash ^= desc->gravity << 28;

  return hash;
}

/**
 * pango_font_description_free:
 * @desc: a #PangoFontDescription
 *
 * Frees a font description.
 **/
void
pango_font_description_free  (PangoFontDescription  *desc)
{
  if (desc)
    {
      if (desc->family_name && !desc->static_family)
	g_free (desc->family_name);

      g_slice_free (PangoFontDescription, desc);
    }
}

/**
 * pango_font_descriptions_free:
 * @descs: a pointer to an array of #PangoFontDescription
 * @n_descs: number of font descriptions in @descs
 *
 * Frees a list of font descriptions from pango_font_map_list_fonts()
 **/
void
pango_font_descriptions_free (PangoFontDescription **descs,
			      int                    n_descs)
{
  int i;

  if (descs)
    {
      for (i = 0; i<n_descs; i++)
	pango_font_description_free (descs[i]);
      g_free (descs);
    }
}

typedef struct
{
  int value;
  const char str[16];
} FieldMap;

static const FieldMap style_map[] = {
  { PANGO_STYLE_NORMAL, "" },
  { PANGO_STYLE_OBLIQUE, "Oblique" },
  { PANGO_STYLE_ITALIC, "Italic" }
};

static const FieldMap variant_map[] = {
  { PANGO_VARIANT_NORMAL, "" },
  { PANGO_VARIANT_SMALL_CAPS, "Small-Caps" }
};

static const FieldMap weight_map[] = {
  { PANGO_WEIGHT_ULTRALIGHT, "Ultra-Light" },
  { PANGO_WEIGHT_LIGHT, "Light" },
  { PANGO_WEIGHT_NORMAL, "" },
  { 500, "Medium" },
  { PANGO_WEIGHT_SEMIBOLD, "Semi-Bold" },
  { PANGO_WEIGHT_BOLD, "Bold" },
  { PANGO_WEIGHT_ULTRABOLD, "Ultra-Bold" },
  { PANGO_WEIGHT_HEAVY, "Heavy" }
};

static const FieldMap stretch_map[] = {
  { PANGO_STRETCH_ULTRA_CONDENSED, "Ultra-Condensed" },
  { PANGO_STRETCH_EXTRA_CONDENSED, "Extra-Condensed" },
  { PANGO_STRETCH_CONDENSED,       "Condensed" },
  { PANGO_STRETCH_SEMI_CONDENSED,  "Semi-Condensed" },
  { PANGO_STRETCH_NORMAL,          "" },
  { PANGO_STRETCH_SEMI_EXPANDED,   "Semi-Expanded" },
  { PANGO_STRETCH_EXPANDED,        "Expanded" },
  { PANGO_STRETCH_EXTRA_EXPANDED,  "Extra-Expanded" },
  { PANGO_STRETCH_ULTRA_EXPANDED,  "Ultra-Expanded" }
};

static const FieldMap gravity_map[] = {
  { PANGO_GRAVITY_SOUTH, "Not-Rotated" },
  { PANGO_GRAVITY_SOUTH, "South" },
  { PANGO_GRAVITY_SOUTH, "Upside-Down" },
  { PANGO_GRAVITY_NORTH, "North" },
  { PANGO_GRAVITY_EAST,  "Rotated-Left" },
  { PANGO_GRAVITY_EAST,  "East" },
  { PANGO_GRAVITY_WEST,  "Rotated-Right" },
  { PANGO_GRAVITY_WEST,  "West" }
};

static gboolean
find_field (const FieldMap *map, int n_elements, const char *str, int len, int *val)
{
  int i;

  for (i=0; i<n_elements; i++)
    {
      if (map[i].str[0] && g_ascii_strncasecmp (map[i].str, str, len) == 0 &&
	  map[i].str[len] == '\0')
	{
	  if (val)
	    *val = map[i].value;
	  return TRUE;
	}
    }

  return FALSE;
}

static gboolean
find_field_any (const char *str, int len, PangoFontDescription *desc)
{
  gboolean found = FALSE;

  if (g_ascii_strcasecmp (str, "Normal") == 0)
    return TRUE;

#define FIELD(NAME, MASK) \
  G_STMT_START { \
  if (find_field (NAME##_map, G_N_ELEMENTS (NAME##_map), str, len, \
		  desc ? (int *)&desc->NAME : NULL)) \
    { \
      found = TRUE; \
      if (desc) \
	desc->mask |= MASK; \
    } \
  } G_STMT_END