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Diffstat (limited to 'pango2/pango-glyph-iter-private.h')
| -rw-r--r-- | pango2/pango-glyph-iter-private.h | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/pango2/pango-glyph-iter-private.h b/pango2/pango-glyph-iter-private.h new file mode 100644 index 00000000..5321b33d --- /dev/null +++ b/pango2/pango-glyph-iter-private.h @@ -0,0 +1,110 @@ +/* + * Copyright (C) 2002 Red Hat Software + * + * SPDX-License-Identifier: LGPL-2.1-or-later + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see <http://www.gnu.org/licenses/>. + */ + +#pragma once + +#include "pango-glyph-item-private.h" + +G_BEGIN_DECLS + +/** + * Pango2GlyphItemIter: + * + * A `Pango2GlyphItemIter` is an iterator over the clusters in a + * `Pango2GlyphItem`. + * + * The *forward direction* of the iterator is the logical direction of text. + * That is, with increasing @start_index and @start_char values. If @glyph_item + * is right-to-left (that is, if `glyph_item->item->analysis.level` is odd), + * then @start_glyph decreases as the iterator moves forward. Moreover, + * in right-to-left cases, @start_glyph is greater than @end_glyph. + * + * An iterator should be initialized using either + * [method@Pango2.GlyphItemIter.init_start] or + * [method@Pango2.GlyphItemIter.init_end], for forward and backward iteration + * respectively, and walked over using any desired mixture of + * [method@Pango2.GlyphItemIter.next_cluster] and + * [method@Pango2.GlyphItemIter.prev_cluster]. + * + * A common idiom for doing a forward iteration over the clusters is: + * + * ``` + * Pango2GlyphItemIter cluster_iter; + * gboolean have_cluster; + * + * for (have_cluster = pango2_glyph_item_iter_init_start (&cluster_iter, + * glyph_item, text); + * have_cluster; + * have_cluster = pango2_glyph_item_iter_next_cluster (&cluster_iter)) + * { + * ... + * } + * ``` + * + * Note that @text is the start of the text for layout, which is then + * indexed by `glyph_item->item->offset` to get to the text of @glyph_item. + * The @start_index and @end_index values can directly index into @text. The + * @start_glyph, @end_glyph, @start_char, and @end_char values however are + * zero-based for the @glyph_item. For each cluster, the item pointed at by + * the start variables is included in the cluster while the one pointed at by + * end variables is not. + * + * None of the members of a `Pango2GlyphItemIter` should be modified manually. + */ +typedef struct _Pango2GlyphItemIter Pango2GlyphItemIter; + +struct _Pango2GlyphItemIter +{ + Pango2GlyphItem *glyph_item; + const char *text; + + int start_glyph; + int start_index; + int start_char; + + int end_glyph; + int end_index; + int end_char; +}; + +#define PANGO2_TYPE_GLYPH_ITEM_ITER (pango2_glyph_item_iter_get_type ()) + +PANGO2_AVAILABLE_IN_ALL +GType pango2_glyph_item_iter_get_type (void) G_GNUC_CONST; +PANGO2_AVAILABLE_IN_ALL +Pango2GlyphItemIter * pango2_glyph_item_iter_copy (Pango2GlyphItemIter *orig); +PANGO2_AVAILABLE_IN_ALL +void pango2_glyph_item_iter_free (Pango2GlyphItemIter *iter); + +PANGO2_AVAILABLE_IN_ALL +gboolean pango2_glyph_item_iter_init_start (Pango2GlyphItemIter *iter, + Pango2GlyphItem *glyph_item, + const char *text); +PANGO2_AVAILABLE_IN_ALL +gboolean pango2_glyph_item_iter_init_end (Pango2GlyphItemIter *iter, + Pango2GlyphItem *glyph_item, + const char *text); +PANGO2_AVAILABLE_IN_ALL +gboolean pango2_glyph_item_iter_next_cluster (Pango2GlyphItemIter *iter); +PANGO2_AVAILABLE_IN_ALL +gboolean pango2_glyph_item_iter_prev_cluster (Pango2GlyphItemIter *iter); + +G_DEFINE_AUTOPTR_CLEANUP_FUNC(Pango2GlyphItemIter, pango2_glyph_item_iter_free) + +G_END_DECLS |