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/* Pango
* reorder-items.c:
*
* Copyright (C) 1999 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 "pango-glyph.h"
/*
* NB: The contents of the file implement the exact same algorithm
* pango-layout.c:pango_layout_line_reorder().
*/
static GList *reorder_items_recurse (GList *items, int n_items);
/**
* pango_reorder_items:
* @logical_items: (element-type Pango.Item): a #GList of #PangoItem in logical order.
*
* From a list of items in logical order and the associated
* directional levels, produce a list in visual order.
* The original list is unmodified.
*
* Returns: (transfer full) (element-type Pango.Item): a #GList
* of #PangoItem structures in visual order.
*
* (Please open a bug if you use this function.
* It is not a particularly convenient interface, and the code
* is duplicated elsewhere in Pango for that reason.)
*/
GList *
pango_reorder_items (GList *logical_items)
{
return reorder_items_recurse (logical_items, g_list_length (logical_items));
}
static GList *
reorder_items_recurse (GList *items, int n_items)
{
GList *tmp_list, *level_start_node;
int i, level_start_i;
int min_level = G_MAXINT;
GList *result = NULL;
if (n_items == 0)
return NULL;
tmp_list = items;
for (i=0; i<n_items; i++)
{
PangoItem *item = tmp_list->data;
min_level = MIN (min_level, item->analysis.level);
tmp_list = tmp_list->next;
}
level_start_i = 0;
level_start_node = items;
tmp_list = items;
for (i=0; i<n_items; i++)
{
PangoItem *item = tmp_list->data;
if (item->analysis.level == min_level)
{
if (min_level % 2)
{
if (i > level_start_i)
result = g_list_concat (reorder_items_recurse (level_start_node, i - level_start_i), result);
result = g_list_prepend (result, item);
}
else
{
if (i > level_start_i)
result = g_list_concat (result, reorder_items_recurse (level_start_node, i - level_start_i));
result = g_list_append (result, item);
}
level_start_i = i + 1;
level_start_node = tmp_list->next;
}
tmp_list = tmp_list->next;
}
if (min_level % 2)
{
if (i > level_start_i)
result = g_list_concat (reorder_items_recurse (level_start_node, i - level_start_i), result);
}
else
{
if (i > level_start_i)
result = g_list_concat (result, reorder_items_recurse (level_start_node, i - level_start_i));
}
return result;
}
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