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a11y: implementation for atk_text_get_text_[before/at/after]_offset

Copy and paste of the implementation done at Gtk+ based on pango. This
should be moved to a common library, like the old GailTextUtil. Ideally
on pango itself.

https://bugzilla.gnome.org/show_bug.cgi?id=677221
This commit is contained in:
Alejandro Piñeiro 2012-06-05 14:56:31 +02:00
parent a571c2933b
commit dd7c1ed64a

View file

@ -8,6 +8,10 @@
* GAIL - The GNOME Accessibility Implementation Library
* Copyright 2001, 2002, 2003 Sun Microsystems Inc.
*
* Implementation of atk_text_get_text_[before/at/after]_offset
* copied from gtkpango.c, part of GTK+ project
* Copyright (c) 2010 Red Hat, Inc.
*
* 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
@ -368,6 +372,706 @@ cally_text_ref_state_set (AtkObject *obj)
return result;
}
/***** pango stuff ****
*
* FIXME: all this pango related code used to implement
* atk_text_get_text_[before/at/after]_offset was copied from GTK, and
* should be on a common library (like pango itself).
*
*********************/
/*
* _gtk_pango_move_chars:
* @layout: a #PangoLayout
* @offset: a character offset in @layout
* @count: the number of characters to move from @offset
*
* Returns the position that is @count characters from the
* given @offset. @count may be positive or negative.
*
* For the purpose of this function, characters are defined
* by what Pango considers cursor positions.
*
* Returns: the new position
*/
static gint
_gtk_pango_move_chars (PangoLayout *layout,
gint offset,
gint count)
{
const PangoLogAttr *attrs;
gint n_attrs;
attrs = pango_layout_get_log_attrs_readonly (layout, &n_attrs);
while (count > 0 && offset < n_attrs - 1)
{
do
offset++;
while (offset < n_attrs - 1 && !attrs[offset].is_cursor_position);
count--;
}
while (count < 0 && offset > 0)
{
do
offset--;
while (offset > 0 && !attrs[offset].is_cursor_position);
count++;
}
return offset;
}
/*
* _gtk_pango_move_words:
* @layout: a #PangoLayout
* @offset: a character offset in @layout
* @count: the number of words to move from @offset
*
* Returns the position that is @count words from the
* given @offset. @count may be positive or negative.
*
* If @count is positive, the returned position will
* be a word end, otherwise it will be a word start.
* See the Pango documentation for details on how
* word starts and ends are defined.
*
* Returns: the new position
*/
static gint
_gtk_pango_move_words (PangoLayout *layout,
gint offset,
gint count)
{
const PangoLogAttr *attrs;
gint n_attrs;
attrs = pango_layout_get_log_attrs_readonly (layout, &n_attrs);
while (count > 0 && offset < n_attrs - 1)
{
do
offset++;
while (offset < n_attrs - 1 && !attrs[offset].is_word_end);
count--;
}
while (count < 0 && offset > 0)
{
do
offset--;
while (offset > 0 && !attrs[offset].is_word_start);
count++;
}
return offset;
}
/*
* _gtk_pango_move_sentences:
* @layout: a #PangoLayout
* @offset: a character offset in @layout
* @count: the number of sentences to move from @offset
*
* Returns the position that is @count sentences from the
* given @offset. @count may be positive or negative.
*
* If @count is positive, the returned position will
* be a sentence end, otherwise it will be a sentence start.
* See the Pango documentation for details on how
* sentence starts and ends are defined.
*
* Returns: the new position
*/
static gint
_gtk_pango_move_sentences (PangoLayout *layout,
gint offset,
gint count)
{
const PangoLogAttr *attrs;
gint n_attrs;
attrs = pango_layout_get_log_attrs_readonly (layout, &n_attrs);
while (count > 0 && offset < n_attrs - 1)
{
do
offset++;
while (offset < n_attrs - 1 && !attrs[offset].is_sentence_end);
count--;
}
while (count < 0 && offset > 0)
{
do
offset--;
while (offset > 0 && !attrs[offset].is_sentence_start);
count++;
}
return offset;
}
/*
* _gtk_pango_is_inside_word:
* @layout: a #PangoLayout
* @offset: a character offset in @layout
*
* Returns whether the given position is inside
* a word.
*
* Returns: %TRUE if @offset is inside a word
*/
static gboolean
_gtk_pango_is_inside_word (PangoLayout *layout,
gint offset)
{
const PangoLogAttr *attrs;
gint n_attrs;
attrs = pango_layout_get_log_attrs_readonly (layout, &n_attrs);
while (offset >= 0 &&
!(attrs[offset].is_word_start || attrs[offset].is_word_end))
offset--;
if (offset >= 0)
return attrs[offset].is_word_start;
return FALSE;
}
/*
* _gtk_pango_is_inside_sentence:
* @layout: a #PangoLayout
* @offset: a character offset in @layout
*
* Returns whether the given position is inside
* a sentence.
*
* Returns: %TRUE if @offset is inside a sentence
*/
static gboolean
_gtk_pango_is_inside_sentence (PangoLayout *layout,
gint offset)
{
const PangoLogAttr *attrs;
gint n_attrs;
attrs = pango_layout_get_log_attrs_readonly (layout, &n_attrs);
while (offset >= 0 &&
!(attrs[offset].is_sentence_start || attrs[offset].is_sentence_end))
offset--;
if (offset >= 0)
return attrs[offset].is_sentence_start;
return FALSE;
}
static void
pango_layout_get_line_before (PangoLayout *layout,
AtkTextBoundary boundary_type,
gint offset,
gint *start_offset,
gint *end_offset)
{
PangoLayoutIter *iter;
PangoLayoutLine *line, *prev_line = NULL, *prev_prev_line = NULL;
gint index, start_index, end_index;
const gchar *text;
gboolean found = FALSE;
text = pango_layout_get_text (layout);
index = g_utf8_offset_to_pointer (text, offset) - text;
iter = pango_layout_get_iter (layout);
do
{
line = pango_layout_iter_get_line (iter);
start_index = line->start_index;
end_index = start_index + line->length;
if (index >= start_index && index <= end_index)
{
/* Found line for offset */
if (prev_line)
{
switch (boundary_type)
{
case ATK_TEXT_BOUNDARY_LINE_START:
end_index = start_index;
start_index = prev_line->start_index;
break;
case ATK_TEXT_BOUNDARY_LINE_END:
if (prev_prev_line)
start_index = prev_prev_line->start_index + prev_prev_line->length;
else
start_index = 0;
end_index = prev_line->start_index + prev_line->length;
break;
default:
g_assert_not_reached();
}
}
else
start_index = end_index = 0;
found = TRUE;
break;
}
prev_prev_line = prev_line;
prev_line = line;
}
while (pango_layout_iter_next_line (iter));
if (!found)
{
start_index = prev_line->start_index + prev_line->length;
end_index = start_index;
}
pango_layout_iter_free (iter);
*start_offset = g_utf8_pointer_to_offset (text, text + start_index);
*end_offset = g_utf8_pointer_to_offset (text, text + end_index);
}
static void
pango_layout_get_line_at (PangoLayout *layout,
AtkTextBoundary boundary_type,
gint offset,
gint *start_offset,
gint *end_offset)
{
PangoLayoutIter *iter;
PangoLayoutLine *line, *prev_line = NULL;
gint index, start_index, end_index;
const gchar *text;
gboolean found = FALSE;
text = pango_layout_get_text (layout);
index = g_utf8_offset_to_pointer (text, offset) - text;
iter = pango_layout_get_iter (layout);
do
{
line = pango_layout_iter_get_line (iter);
start_index = line->start_index;
end_index = start_index + line->length;
if (index >= start_index && index <= end_index)
{
/* Found line for offset */
switch (boundary_type)
{
case ATK_TEXT_BOUNDARY_LINE_START:
if (pango_layout_iter_next_line (iter))
end_index = pango_layout_iter_get_line (iter)->start_index;
break;
case ATK_TEXT_BOUNDARY_LINE_END:
if (prev_line)
start_index = prev_line->start_index + prev_line->length;
break;
default:
g_assert_not_reached();
}
found = TRUE;
break;
}
prev_line = line;
}
while (pango_layout_iter_next_line (iter));
if (!found)
{
start_index = prev_line->start_index + prev_line->length;
end_index = start_index;
}
pango_layout_iter_free (iter);
*start_offset = g_utf8_pointer_to_offset (text, text + start_index);
*end_offset = g_utf8_pointer_to_offset (text, text + end_index);
}
static void
pango_layout_get_line_after (PangoLayout *layout,
AtkTextBoundary boundary_type,
gint offset,
gint *start_offset,
gint *end_offset)
{
PangoLayoutIter *iter;
PangoLayoutLine *line, *prev_line = NULL;
gint index, start_index, end_index;
const gchar *text;
gboolean found = FALSE;
text = pango_layout_get_text (layout);
index = g_utf8_offset_to_pointer (text, offset) - text;
iter = pango_layout_get_iter (layout);
do
{
line = pango_layout_iter_get_line (iter);
start_index = line->start_index;
end_index = start_index + line->length;
if (index >= start_index && index <= end_index)
{
/* Found line for offset */
if (pango_layout_iter_next_line (iter))
{
line = pango_layout_iter_get_line (iter);
switch (boundary_type)
{
case ATK_TEXT_BOUNDARY_LINE_START:
start_index = line->start_index;
if (pango_layout_iter_next_line (iter))
end_index = pango_layout_iter_get_line (iter)->start_index;
else
end_index = start_index + line->length;
break;
case ATK_TEXT_BOUNDARY_LINE_END:
start_index = end_index;
end_index = line->start_index + line->length;
break;
default:
g_assert_not_reached();
}
}
else
start_index = end_index;
found = TRUE;
break;
}
prev_line = line;
}
while (pango_layout_iter_next_line (iter));
if (!found)
{
start_index = prev_line->start_index + prev_line->length;
end_index = start_index;
}
pango_layout_iter_free (iter);
*start_offset = g_utf8_pointer_to_offset (text, text + start_index);
*end_offset = g_utf8_pointer_to_offset (text, text + end_index);
}
/*
* _gtk_pango_get_text_at:
* @layout: a #PangoLayout
* @boundary_type: a #AtkTextBoundary
* @offset: a character offset in @layout
* @start_offset: return location for the start of the returned text
* @end_offset: return location for the end of the return text
*
* Gets a slice of the text from @layout at @offset.
*
* The @boundary_type determines the size of the returned slice of
* text. For the exact semantics of this function, see
* atk_text_get_text_after_offset().
*
* Returns: a newly allocated string containing a slice of text
* from layout. Free with g_free().
*/
static gchar *
_gtk_pango_get_text_at (PangoLayout *layout,
AtkTextBoundary boundary_type,
gint offset,
gint *start_offset,
gint *end_offset)
{
const gchar *text;
gint start, end;
const PangoLogAttr *attrs;
gint n_attrs;
text = pango_layout_get_text (layout);
if (text[0] == 0)
{
*start_offset = 0;
*end_offset = 0;
return g_strdup ("");
}
attrs = pango_layout_get_log_attrs_readonly (layout, &n_attrs);
start = offset;
end = start;
switch (boundary_type)
{
case ATK_TEXT_BOUNDARY_CHAR:
end = _gtk_pango_move_chars (layout, end, 1);
break;
case ATK_TEXT_BOUNDARY_WORD_START:
if (!attrs[start].is_word_start)
start = _gtk_pango_move_words (layout, start, -1);
if (_gtk_pango_is_inside_word (layout, end))
end = _gtk_pango_move_words (layout, end, 1);
while (!attrs[end].is_word_start && end < n_attrs - 1)
end = _gtk_pango_move_chars (layout, end, 1);
break;
case ATK_TEXT_BOUNDARY_WORD_END:
if (_gtk_pango_is_inside_word (layout, start) &&
!attrs[start].is_word_start)
start = _gtk_pango_move_words (layout, start, -1);
while (!attrs[start].is_word_end && start > 0)
start = _gtk_pango_move_chars (layout, start, -1);
end = _gtk_pango_move_words (layout, end, 1);
break;
case ATK_TEXT_BOUNDARY_SENTENCE_START:
if (!attrs[start].is_sentence_start)
start = _gtk_pango_move_sentences (layout, start, -1);
if (_gtk_pango_is_inside_sentence (layout, end))
end = _gtk_pango_move_sentences (layout, end, 1);
while (!attrs[end].is_sentence_start && end < n_attrs - 1)
end = _gtk_pango_move_chars (layout, end, 1);
break;
case ATK_TEXT_BOUNDARY_SENTENCE_END:
if (_gtk_pango_is_inside_sentence (layout, start) &&
!attrs[start].is_sentence_start)
start = _gtk_pango_move_sentences (layout, start, -1);
while (!attrs[start].is_sentence_end && start > 0)
start = _gtk_pango_move_chars (layout, start, -1);
end = _gtk_pango_move_sentences (layout, end, 1);
break;
case ATK_TEXT_BOUNDARY_LINE_START:
case ATK_TEXT_BOUNDARY_LINE_END:
pango_layout_get_line_at (layout, boundary_type, offset, &start, &end);
break;
}
*start_offset = start;
*end_offset = end;
g_assert (start <= end);
return g_utf8_substring (text, start, end);
}
/*
* _gtk_pango_get_text_before:
* @layout: a #PangoLayout
* @boundary_type: a #AtkTextBoundary
* @offset: a character offset in @layout
* @start_offset: return location for the start of the returned text
* @end_offset: return location for the end of the return text
*
* Gets a slice of the text from @layout before @offset.
*
* The @boundary_type determines the size of the returned slice of
* text. For the exact semantics of this function, see
* atk_text_get_text_before_offset().
*
* Returns: a newly allocated string containing a slice of text
* from layout. Free with g_free().
*/
static gchar *
_gtk_pango_get_text_before (PangoLayout *layout,
AtkTextBoundary boundary_type,
gint offset,
gint *start_offset,
gint *end_offset)
{
const gchar *text;
gint start, end;
const PangoLogAttr *attrs;
gint n_attrs;
text = pango_layout_get_text (layout);
if (text[0] == 0)
{
*start_offset = 0;
*end_offset = 0;
return g_strdup ("");
}
attrs = pango_layout_get_log_attrs_readonly (layout, &n_attrs);
start = offset;
end = start;
switch (boundary_type)
{
case ATK_TEXT_BOUNDARY_CHAR:
start = _gtk_pango_move_chars (layout, start, -1);
break;
case ATK_TEXT_BOUNDARY_WORD_START:
if (!attrs[start].is_word_start)
start = _gtk_pango_move_words (layout, start, -1);
end = start;
start = _gtk_pango_move_words (layout, start, -1);
break;
case ATK_TEXT_BOUNDARY_WORD_END:
if (_gtk_pango_is_inside_word (layout, start) &&
!attrs[start].is_word_start)
start = _gtk_pango_move_words (layout, start, -1);
while (!attrs[start].is_word_end && start > 0)
start = _gtk_pango_move_chars (layout, start, -1);
end = start;
start = _gtk_pango_move_words (layout, start, -1);
while (!attrs[start].is_word_end && start > 0)
start = _gtk_pango_move_chars (layout, start, -1);
break;
case ATK_TEXT_BOUNDARY_SENTENCE_START:
if (!attrs[start].is_sentence_start)
start = _gtk_pango_move_sentences (layout, start, -1);
end = start;
start = _gtk_pango_move_sentences (layout, start, -1);
break;
case ATK_TEXT_BOUNDARY_SENTENCE_END:
if (_gtk_pango_is_inside_sentence (layout, start) &&
!attrs[start].is_sentence_start)
start = _gtk_pango_move_sentences (layout, start, -1);
while (!attrs[start].is_sentence_end && start > 0)
start = _gtk_pango_move_chars (layout, start, -1);
end = start;
start = _gtk_pango_move_sentences (layout, start, -1);
while (!attrs[start].is_sentence_end && start > 0)
start = _gtk_pango_move_chars (layout, start, -1);
break;
case ATK_TEXT_BOUNDARY_LINE_START:
case ATK_TEXT_BOUNDARY_LINE_END:
pango_layout_get_line_before (layout, boundary_type, offset, &start, &end);
break;
}
*start_offset = start;
*end_offset = end;
g_assert (start <= end);
return g_utf8_substring (text, start, end);
}
/*
* _gtk_pango_get_text_after:
* @layout: a #PangoLayout
* @boundary_type: a #AtkTextBoundary
* @offset: a character offset in @layout
* @start_offset: return location for the start of the returned text
* @end_offset: return location for the end of the return text
*
* Gets a slice of the text from @layout after @offset.
*
* The @boundary_type determines the size of the returned slice of
* text. For the exact semantics of this function, see
* atk_text_get_text_after_offset().
*
* Returns: a newly allocated string containing a slice of text
* from layout. Free with g_free().
*/
static gchar *
_gtk_pango_get_text_after (PangoLayout *layout,
AtkTextBoundary boundary_type,
gint offset,
gint *start_offset,
gint *end_offset)
{
const gchar *text;
gint start, end;
const PangoLogAttr *attrs;
gint n_attrs;
text = pango_layout_get_text (layout);
if (text[0] == 0)
{
*start_offset = 0;
*end_offset = 0;
return g_strdup ("");
}
attrs = pango_layout_get_log_attrs_readonly (layout, &n_attrs);
start = offset;
end = start;
switch (boundary_type)
{
case ATK_TEXT_BOUNDARY_CHAR:
start = _gtk_pango_move_chars (layout, start, 1);
end = start;
end = _gtk_pango_move_chars (layout, end, 1);
break;
case ATK_TEXT_BOUNDARY_WORD_START:
if (_gtk_pango_is_inside_word (layout, end))
end = _gtk_pango_move_words (layout, end, 1);
while (!attrs[end].is_word_start && end < n_attrs - 1)
end = _gtk_pango_move_chars (layout, end, 1);
start = end;
if (end < n_attrs - 1)
{
end = _gtk_pango_move_words (layout, end, 1);
while (!attrs[end].is_word_start && end < n_attrs - 1)
end = _gtk_pango_move_chars (layout, end, 1);
}
break;
case ATK_TEXT_BOUNDARY_WORD_END:
end = _gtk_pango_move_words (layout, end, 1);
start = end;
if (end < n_attrs - 1)
end = _gtk_pango_move_words (layout, end, 1);
break;
case ATK_TEXT_BOUNDARY_SENTENCE_START:
if (_gtk_pango_is_inside_sentence (layout, end))
end = _gtk_pango_move_sentences (layout, end, 1);
while (!attrs[end].is_sentence_start && end < n_attrs - 1)
end = _gtk_pango_move_chars (layout, end, 1);
start = end;
if (end < n_attrs - 1)
{
end = _gtk_pango_move_sentences (layout, end, 1);
while (!attrs[end].is_sentence_start && end < n_attrs - 1)
end = _gtk_pango_move_chars (layout, end, 1);
}
break;
case ATK_TEXT_BOUNDARY_SENTENCE_END:
end = _gtk_pango_move_sentences (layout, end, 1);
start = end;
if (end < n_attrs - 1)
end = _gtk_pango_move_sentences (layout, end, 1);
break;
case ATK_TEXT_BOUNDARY_LINE_START:
case ATK_TEXT_BOUNDARY_LINE_END:
pango_layout_get_line_after (layout, boundary_type, offset, &start, &end);
break;
}
*start_offset = start;
*end_offset = end;
g_assert (start <= end);
return g_utf8_substring (text, start, end);
}
/***** atktext.h ******/
@ -449,28 +1153,14 @@ cally_text_get_text_before_offset (AtkText *text,
gint *end_offset)
{
ClutterActor *actor = NULL;
#if 0
ClutterText *clutter_text = NULL;
CallyText *cally_text = NULL;
#endif
actor = CALLY_GET_CLUTTER_ACTOR (text);
if (actor == NULL) /* State is defunct */
return NULL;
#if 0
clutter_text = CLUTTER_TEXT (actor);
cally_text = CALLY_TEXT (text);
return gail_text_util_get_text (cally_text->priv->textutil,
clutter_text_get_layout (clutter_text),
GAIL_BEFORE_OFFSET,
boundary_type,
offset,
return _gtk_pango_get_text_before (clutter_text_get_layout (CLUTTER_TEXT (actor)),
boundary_type, offset,
start_offset, end_offset);
#endif
return NULL;
}
static gchar*
@ -481,28 +1171,14 @@ cally_text_get_text_at_offset (AtkText *text,
gint *end_offset)
{
ClutterActor *actor = NULL;
#if 0
ClutterText *clutter_text = NULL;
CallyText *cally_text = NULL;
#endif
actor = CALLY_GET_CLUTTER_ACTOR (text);
if (actor == NULL) /* State is defunct */
return NULL;
#if 0
clutter_text = CLUTTER_TEXT (actor);
cally_text = CALLY_TEXT (text);
return gail_text_util_get_text (cally_text->priv->textutil,
clutter_text_get_layout (clutter_text),
GAIL_AT_OFFSET,
boundary_type,
offset,
return _gtk_pango_get_text_at (clutter_text_get_layout (CLUTTER_TEXT (actor)),
boundary_type, offset,
start_offset, end_offset);
#endif
return NULL;
}
static gchar*
@ -513,28 +1189,14 @@ cally_text_get_text_after_offset (AtkText *text,
gint *end_offset)
{
ClutterActor *actor = NULL;
#if 0
ClutterText *clutter_text = NULL;
CallyText *cally_text = NULL;
#endif
actor = CALLY_GET_CLUTTER_ACTOR (text);
if (actor == NULL) /* State is defunct */
return NULL;
#if 0
clutter_text = CLUTTER_TEXT (actor);
cally_text = CALLY_TEXT (text);
return gail_text_util_get_text (cally_text->priv->textutil,
clutter_text_get_layout (clutter_text),
GAIL_AFTER_OFFSET,
boundary_type,
offset,
return _gtk_pango_get_text_after (clutter_text_get_layout (CLUTTER_TEXT (actor)),
boundary_type, offset,
start_offset, end_offset);
#endif
return NULL;
}
static gint