pango-glyph-item.c

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

/* Pango
 * pango-glyph-item.c: Pair of PangoItem and a glyph string
 *
 * Copyright (C) 2002 Red Hat Software
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include <config.h>
#include <string.h>

#include "pango-glyph-item.h"
#include "pango-glyph-item-private.h"
#include "pango-impl-utils.h"

#define LTR(glyph_item) (((glyph_item)->item->analysis.level % 2) == 0)

/**
 * pango_glyph_item_split:
 * @orig: a #PangoItem
 * @text: text to which positions in @orig apply
 * @split_index: byte index of position to split item, relative to the start of the item
 *
 * Modifies @orig to cover only the text after @split_index, and
 * returns a new item that covers the text before @split_index that
 * used to be in @orig. You can think of @split_index as the length of
 * the returned item. @split_index may not be 0, and it may not be
 * greater than or equal to the length of @orig (that is, there must
 * be at least one byte assigned to each item, you can't create a
 * zero-length item).
 *
 * This function is similar in function to pango_item_split() (and uses
 * it internally.)
 *
 * Return value: the newly allocated item representing text before
 *               @split_index, which should be freed
 *               with pango_glyph_item_free().
 *
 * Since: 1.2
 **/
PangoGlyphItem *
pango_glyph_item_split (PangoGlyphItem *orig,
			const char     *text,
			int             split_index)
{
  PangoGlyphItem *new;
  int i;
  int num_glyphs;
  int num_remaining;
  int split_offset;

  g_return_val_if_fail (orig != NULL, NULL);
  g_return_val_if_fail (orig->item->length > 0, NULL);
  g_return_val_if_fail (split_index > 0, NULL);
  g_return_val_if_fail (split_index < orig->item->length, NULL);

  if (LTR (orig))
    {
      for (i = 0; i < orig->glyphs->num_glyphs; i++)
	{
	  if (orig->glyphs->log_clusters[i] >= split_index)
	    break;
	}

      if (i == orig->glyphs->num_glyphs) /* No splitting necessary */
	return NULL;

      split_index = orig->glyphs->log_clusters[i];
      num_glyphs = i;
    }
  else
    {
      for (i = orig->glyphs->num_glyphs - 1; i >= 0; i--)
	{
	  if (orig->glyphs->log_clusters[i] >= split_index)
	    break;
	}

      if (i < 0) /* No splitting necessary */
	return NULL;

      split_index = orig->glyphs->log_clusters[i];
      num_glyphs = orig->glyphs->num_glyphs - 1 - i;
    }

  num_remaining = orig->glyphs->num_glyphs - num_glyphs;

  new = g_slice_new (PangoGlyphItem);
  split_offset = g_utf8_pointer_to_offset (text + orig->item->offset,
					   text + orig->item->offset + split_index);
  new->item = pango_item_split (orig->item, split_index, split_offset);

  new->glyphs = pango_glyph_string_new ();
  pango_glyph_string_set_size (new->glyphs, num_glyphs);

  if (LTR (orig))
    {
      memcpy (new->glyphs->glyphs, orig->glyphs->glyphs, num_glyphs * sizeof (PangoGlyphInfo));
      memcpy (new->glyphs->log_clusters, orig->glyphs->log_clusters, num_glyphs * sizeof (int));

      memmove (orig->glyphs->glyphs, orig->glyphs->glyphs + num_glyphs,
	       num_remaining * sizeof (PangoGlyphInfo));
      for (i = num_glyphs; i < orig->glyphs->num_glyphs; i++)
	orig->glyphs->log_clusters[i - num_glyphs] = orig->glyphs->log_clusters[i] - split_index;
    }
  else
    {
      memcpy (new->glyphs->glyphs, orig->glyphs->glyphs + num_remaining, num_glyphs * sizeof (PangoGlyphInfo));
      memcpy (new->glyphs->log_clusters, orig->glyphs->log_clusters + num_remaining, num_glyphs * sizeof (int));

      for (i = 0; i < num_remaining; i++)
	orig->glyphs->log_clusters[i] = orig->glyphs->log_clusters[i] - split_index;
    }

  pango_glyph_string_set_size (orig->glyphs, orig->glyphs->num_glyphs - num_glyphs);

  return new;
}

/**
 * pango_glyph_item_copy:
 * @orig: a #PangoGlyphItem, may be %NULL
 *
 * Make a deep copy an existing #PangoGlyphItem structure.
 *
 * Return value: the newly allocated #PangoGlyphItem, which should
 *               be freed with pango_glyph_item_free(), or %NULL
 *               if @orig was %NULL.
 *
 * Since: 1.20
 **/
PangoGlyphItem *
pango_glyph_item_copy  (PangoGlyphItem *orig)
{
  PangoGlyphItem *result;

  if (orig == NULL)
    return NULL;

  result = g_slice_new (PangoGlyphItem);

  result->item = pango_item_copy (orig->item);
  result->glyphs = pango_glyph_string_copy (orig->glyphs);

  return result;
}

/**
 * pango_glyph_item_free:
 * @glyph_item: a #PangoGlyphItem, may be %NULL
 *
 * Frees a #PangoGlyphItem and memory to which it points.
 *
 * Since: 1.6
 **/
void
pango_glyph_item_free  (PangoGlyphItem *glyph_item)
{
  if (glyph_item == NULL)
    return;

  if (glyph_item->item)
    pango_item_free (glyph_item->item);
  if (glyph_item->glyphs)
    pango_glyph_string_free (glyph_item->glyphs);

  g_slice_free (PangoGlyphItem, glyph_item);
}

GType
pango_glyph_item_get_type (void)
{
  static GType our_type = 0;

  if (G_UNLIKELY (our_type == 0))
    our_type = g_boxed_type_register_static (I_("PangoGlyphItem"),
					     (GBoxedCopyFunc) pango_glyph_item_copy,
					     (GBoxedFreeFunc) pango_glyph_item_free);
  return our_type;
}

/**
 * _pango_glyph_item_iter_next_cluster:
 * @iter: a #PangoGlyphItemIter
 *
 * Advances the iterator to the next cluster in the glyph item.
 *
 * Return value: %TRUE if the iterator was advanced, %FALSE if we were already on the
 *  last cluster.
 **/
gboolean
_pango_glyph_item_iter_next_cluster (PangoGlyphItemIter *iter)
{
  int glyph_index = iter->end_glyph;
  PangoGlyphString *glyphs = iter->glyph_item->glyphs;
  int cluster;
  PangoItem *item = iter->glyph_item->item;

  if (LTR (iter->glyph_item))
    {
      if (glyph_index == glyphs->num_glyphs)
	return FALSE;
    }
  else
    {
      if (glyph_index < 0)
	return FALSE;
    }

  iter->start_glyph = iter->end_glyph;
  iter->start_index = iter->end_index;
  iter->start_char = iter->end_char;

  if (LTR (iter->glyph_item))
    {
      cluster = glyphs->log_clusters[glyph_index];
      while (TRUE)
	{
	  glyph_index++;

	  if (glyph_index == glyphs->num_glyphs)
	    {
	      iter->end_index = item->offset + item->length;
	      iter->end_char = item->num_chars;
	      break;
	    }

	  if (glyphs->log_clusters[glyph_index] != cluster)
	    {
	      iter->end_index = item->offset + glyphs->log_clusters[glyph_index];
	      iter->end_char += g_utf8_strlen (iter->text + iter->start_index,
					       iter->end_index - iter->start_index);
	      break;
	    }
	}
    }
  else			/* RTL */
    {
      cluster = glyphs->log_clusters[glyph_index];
      while (TRUE)
	{
	  glyph_index--;

	  if (glyph_index < 0)
	    {
	      iter->end_index = item->offset + item->length;
	      iter->end_char = item->num_chars;
	      break;
	    }

	  if (glyphs->log_clusters[glyph_index] != cluster)
	    {
	      iter->end_index = item->offset + glyphs->log_clusters[glyph_index];
	      iter->end_char += g_utf8_strlen (iter->text + iter->start_index,
					       iter->end_index - iter->start_index);
	      break;
	    }
	}
    }

  iter->end_glyph = glyph_index;
  return TRUE;
}

/**
 * _pango_glyph_item_iter_prev_cluster:
 * @iter: a #PangoGlyphItemIter
 *
 * Moves the iterator to the preceding cluster in the glyph item.
 *
 * Return value: %TRUE if the iterator was moved, %FALSE if we were already on the
 *  first cluster.
 **/
gboolean
_pango_glyph_item_iter_prev_cluster (PangoGlyphItemIter *iter)
{
  int glyph_index = iter->start_glyph;
  PangoGlyphString *glyphs = iter->glyph_item->glyphs;
  int cluster;
  PangoItem *item = iter->glyph_item->item;

  if (LTR (iter->glyph_item))
    {
      if (glyph_index == 0)
	return FALSE;
    }
  else
    {
      if (glyph_index == glyphs->num_glyphs - 1)
	return FALSE;

    }

  iter->end_glyph = iter->start_glyph;
  iter->end_index = iter->start_index;
  iter->end_char = iter->start_char;

  if (LTR (iter->glyph_item))
    {
      cluster = glyphs->log_clusters[glyph_index - 1];
      while (TRUE)
	{
	  glyph_index--;

	  if (glyph_index == 0)
	    {
	      iter->start_index = item->offset;
	      iter->start_char = 0;
	      break;
	    }

	  if (glyphs->log_clusters[glyph_index] != cluster)
	    {
	      glyph_index++;
	      iter->start_index = item->offset + glyphs->log_clusters[glyph_index];
	      iter->start_char -= g_utf8_strlen (iter->text + iter->start_index,
						 iter->end_index - iter->start_index);
	      break;
	    }
	}
    }
  else			/* RTL */
    {
      cluster = glyphs->log_clusters[glyph_index + 1];
      while (TRUE)
	{
	  glyph_index++;

	  if (glyph_index == glyphs->num_glyphs - 1)
	    {
	      iter->start_index = item->offset;
	      iter->start_char = 0;
	      break;
	    }

	  if (glyphs->log_clusters[glyph_index] != cluster)
	    {
	      glyph_index--;
	      iter->start_index = item->offset + glyphs->log_clusters[glyph_index];
	      iter->start_char -= g_utf8_strlen (iter->text + iter->start_index,
						 iter->end_index - iter->start_index);
	      break;
	    }