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Diffstat (limited to 'trunk/pango/reorder-items.c')
-rw-r--r-- | trunk/pango/reorder-items.c | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/trunk/pango/reorder-items.c b/trunk/pango/reorder-items.c new file mode 100644 index 00000000..23ba5836 --- /dev/null +++ b/trunk/pango/reorder-items.c @@ -0,0 +1,114 @@ +/* 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: 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 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; +} |