pango-ot-ruleset.c

linux

/**
 * pango_ot_ruleset_maybe_add_feature:
 * @ruleset: a #PangoOTRuleset.
 * @table_type: the table type to add a feature to.
 * @feature_tag: the tag of the feature to add.
 * @property_bit: the property bit to use for this feature. Used to identify
 *                the glyphs that this feature should be applied to, or
 *                %PANGO_OT_ALL_GLYPHS if it should be applied to all glyphs.
 *
 * This is a convenience function that first tries to find the feature
 * using pango_ot_info_find_feature() and the ruleset script and language
 * passed to pango_ot_ruleset_new_for(),
 * and if the feature is found, adds it to the ruleset.
 *
 * If @ruleset was not created using pango_ot_ruleset_new_for(), this function
 * does nothing.
 *
 * Return value: %TRUE if the feature was found and added to ruleset,
 *               %FALSE otherwise.
 *
 * Since: 1.18
 **/
gboolean
pango_ot_ruleset_maybe_add_feature (PangoOTRuleset          *ruleset,
				    PangoOTTableType         table_type,
				    PangoOTTag               feature_tag,
				    gulong                   property_bit)
{
  guint feature_index;

  g_return_val_if_fail (PANGO_IS_OT_RULESET (ruleset), FALSE);
  g_return_val_if_fail (ruleset->info != NULL, FALSE);

  pango_ot_info_find_feature (ruleset->info, table_type,
			      feature_tag,
			      ruleset->script_index[table_type],
			      ruleset->language_index[table_type],
			      &feature_index);

  if (feature_index != PANGO_OT_NO_FEATURE)
    {
      pango_ot_ruleset_add_feature (ruleset, table_type,
				    feature_index, property_bit);
      return TRUE;
    }

  return FALSE;
}

/**
 * pango_ot_ruleset_maybe_add_features:
 * @ruleset: a #PangoOTRuleset.
 * @table_type: the table type to add features to.
 * @features: array of feature name and property bits to add.
 * @n_features: number of feature records in @features array.
 *
 * This is a convenience function that 
 * for each feature in the feature map array @features
 * converts the feature name to a #PangoOTTag feature tag using FT_MAKE_TAG()
 * and calls pango_ot_ruleset_maybe_add_feature() on it.
 *
 * Return value: The number of features in @features that were found
 *               and added to @ruleset.
 *
 * Since: 1.18
 **/
guint
pango_ot_ruleset_maybe_add_features (PangoOTRuleset          *ruleset,
				     PangoOTTableType         table_type,
				     const PangoOTFeatureMap *features,
				     guint                    n_features)
{
  guint i, n_found_features = 0;

  g_return_val_if_fail (PANGO_IS_OT_RULESET (ruleset), 0);
  g_return_val_if_fail (ruleset->info != NULL, 0);

  for (i = 0; i < n_features; i++)
    {
      PangoOTTag feature_tag = FT_MAKE_TAG (features[i].feature_name[0],
					    features[i].feature_name[1],
					    features[i].feature_name[2],
					    features[i].feature_name[3]);

      n_found_features += pango_ot_ruleset_maybe_add_feature (ruleset,
							      table_type,
							      feature_tag,
							      features[i].property_bit);
    }

  return n_found_features;
}

/**
 * pango_ot_ruleset_get_feature_count:
 * @ruleset: a #PangoOTRuleset.
 * @n_gsub_features: location to store number of GSUB features, or %NULL.
 * @n_gpos_features: location to store number of GPOS features, or %NULL.
 *
 * Gets the number of GSUB and GPOS features in the ruleset.
 *
 * Return value: Total number of features in the @ruleset.
 *
 * Since: 1.18
 **/
guint
pango_ot_ruleset_get_feature_count (const PangoOTRuleset   *ruleset,
				    guint                  *n_gsub_features,
				    guint                  *n_gpos_features)
{
  g_return_val_if_fail (PANGO_IS_OT_RULESET (ruleset), 0);
  
  if (n_gsub_features)
    *n_gsub_features = ruleset->n_features[PANGO_OT_TABLE_GSUB];

  if (n_gpos_features)
    *n_gpos_features = ruleset->n_features[PANGO_OT_TABLE_GPOS];

  return ruleset->n_features[PANGO_OT_TABLE_GSUB] + ruleset->n_features[PANGO_OT_TABLE_GPOS];
}

/**
 * pango_ot_ruleset_substitute:
 * @ruleset: a #PangoOTRuleset.
 * @buffer: a #PangoOTBuffer.
 *
 * Performs the OpenType GSUB substitution on @buffer using the features
 * in @ruleset
 *
 * Since: 1.4
 **/
void
pango_ot_ruleset_substitute  (const PangoOTRuleset *ruleset,
			      PangoOTBuffer        *buffer)
{
  unsigned int i;

  HB_GSUB gsub = NULL;

  g_return_if_fail (PANGO_IS_OT_RULESET (ruleset));
  g_return_if_fail (ruleset->info != NULL);

  for (i = 0; i < ruleset->rules->len; i++)
    {
      PangoOTRule *rule = &g_array_index (ruleset->rules, PangoOTRule, i);

      if (rule->table_type != PANGO_OT_TABLE_GSUB)
	continue;

      if (!gsub)
	{
	  gsub = pango_ot_info_get_gsub (ruleset->info);

	  if (gsub)
	    HB_GSUB_Clear_Features (gsub);
	  else
	    return;
	}

      HB_GSUB_Add_Feature (gsub, rule->feature_index, rule->property_bit);
    }

  HB_GSUB_Apply_String (gsub, buffer->buffer);
}

/**
 * pango_ot_ruleset_position:
 * @ruleset: a #PangoOTRuleset.
 * @buffer: a #PangoOTBuffer.
 *
 * Performs the OpenType GPOS positioning on @buffer using the features
 * in @ruleset
 *
 * Since: 1.4
 **/
void
pango_ot_ruleset_position (const PangoOTRuleset *ruleset,
			   PangoOTBuffer        *buffer)
{
  unsigned int i;

  HB_GPOS gpos = NULL;

  g_return_if_fail (PANGO_IS_OT_RULESET (ruleset));
  g_return_if_fail (ruleset->info != NULL);

  for (i = 0; i < ruleset->rules->len; i++)
    {
      PangoOTRule *rule = &g_array_index (ruleset->rules, PangoOTRule, i);

      if (rule->table_type != PANGO_OT_TABLE_GPOS)
	continue;

      if (!gpos)
	{
	  gpos = pango_ot_info_get_gpos (ruleset->info);

	  if (gpos)
	    HB_GPOS_Clear_Features (gpos);
	  else
	    return;
	}

      HB_GPOS_Add_Feature (gpos, rule->feature_index, rule->property_bit);
    }

  if (HB_GPOS_Apply_String (ruleset->info->face, gpos, 0, buffer->buffer,
			    FALSE /* enable device-dependant values */,
			    buffer->rtl) == FT_Err_Ok)
    buffer->applied_gpos = TRUE;
}

/* ruleset descriptions */

/**
 * pango_ot_ruleset_description_hash:
 * @desc: a ruleset description
 *
 * Computes a hash of a #PangoOTRulesetDescription structure suitable
 * to be used, for example, as an argument to g_hash_table_new().
 *
 * Return value: the hash value.
 *
 * Since: 1.18
 **/
guint
pango_ot_ruleset_description_hash  (const PangoOTRulesetDescription *desc)
{
  guint hash = 0;
  guint i;

  hash ^= desc->script;
  hash ^= GPOINTER_TO_UINT (desc->language);

  hash ^= desc->n_static_gsub_features << 8;
  hash ^= GPOINTER_TO_UINT (desc->static_gsub_features);

  hash ^= desc->n_static_gpos_features << 12;
  hash ^= GPOINTER_TO_UINT (desc->static_gpos_features);

  hash ^= desc->n_other_features << 16;
  for (i = 0; i < desc->n_other_features; i++)
    {
      hash ^= * (guint32 *) desc->other_features[i].feature_name;
      hash ^= desc->other_features[i].property_bit;
    }

  return hash;
}

/**
 * pango_ot_ruleset_description_equal:
 * @desc1: a ruleset description
 * @desc2: a ruleset description
 *
 * Compares two ruleset descriptions for equality.
 * Two ruleset descriptions are considered equal if the rulesets
 * they describe are provably identical.  This means that their
 * script, language, and all feature sets should be equal.  For static feature
 * sets, the array addresses are compared directly, while for other
 * features, the list of features is compared one by one.
 * (Two ruleset descriptions may result in identical rulesets
 * being created, but still compare %FALSE.)
 *
 * Return value: %TRUE if two ruleset descriptions are identical,
 *               %FALSE otherwise.
 *
 * Since: 1.18
 **/
gboolean
pango_ot_ruleset_description_equal (const PangoOTRulesetDescription *desc1,
				    const PangoOTRulesetDescription *desc2)
{
  guint i;

#undef CHECK
#define CHECK(x) if (desc1->x != desc2->x) return FALSE;
#define CHECK_FEATURE_NAME(x) if (*(guint32 *)desc1->x != *(guint32 *)desc2->x) return FALSE

  CHECK (script);
  CHECK (language);

  CHECK (static_gsub_features);
  CHECK (n_static_gsub_features);
  CHECK (static_gpos_features);
  CHECK (n_static_gpos_features);

  CHECK (n_other_features);

  for (i = 0; i < desc1->n_other_features; i++)
    {
      CHECK_FEATURE_NAME (other_features[i].feature_name);
      CHECK (other_features[i].property_bit);
    }

#undef CHECK

  return TRUE;
}

/**
 * pango_ot_ruleset_description_copy:
 * @desc: ruleset description to copy
 *
 * Creates a copy of @desc, which should be freed with
 * pango_ot_ruleset_description_free(). Primarily used internally
 * by pango_ot_ruleset_get_for_description() to cache rulesets for
 * ruleset descriptions.
 *
 * Return value: the newly allocated #PangoOTRulesetDescription, which
 *               should be freed with pango_ot_ruleset_description_free().
 *
 * Since: 1.18
 **/
PangoOTRulesetDescription *
pango_ot_ruleset_description_copy  (const PangoOTRulesetDescription *desc)
{
  PangoOTRulesetDescription *copy;

  g_return_val_if_fail (desc != NULL, NULL);

  copy = g_slice_new (PangoOTRulesetDescription);

  *copy = *desc;

  if (desc->n_other_features)
    {
      PangoOTFeatureMap *map = g_new (PangoOTFeatureMap, desc->n_other_features);
      memcpy (map, desc->other_features, desc->n_other_features * sizeof (PangoOTFeatureMap));
      copy->other_features = map;
    }
  else
    {
      copy->other_features = NULL;
    }

  return copy;
}

/**
 * pango_ot_ruleset_description_free:
 * @desc: an allocated #PangoOTRulesetDescription
 *
 * Frees a ruleset description allocated by 
 * pango_ot_ruleset_description_copy().
 *
 * Since: 1.18
 **/
void
pango_ot_ruleset_description_free  (PangoOTRulesetDescription *desc)
{
  g_return_if_fail (desc != NULL);

  free ((gpointer) desc->other_features);

  g_slice_free (PangoOTRulesetDescription, desc);
}