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A better fix for bug #16148 and related issues.

Browse source 
src/xdisp.c (Fmove_point_visually): Fix subtle bugs in the fallback
 code, revealed in presence of R2L characters, character
 compositions, and display vectors.
 src/dispextern.h (struct composition_it): Correct a comment for the
 'width' member.
This commit is contained in:
Eli Zaretskii 2013-12-16 20:09:36 +02:00
parent 32779713e1
commit 397e886f34
3 changed files with 64 additions and 31 deletions
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9
src/ChangeLog
View file

@ -1,3 +1,12 @@
2013-12-16 Eli Zaretskii <eliz@gnu.org>
* xdisp.c (Fmove_point_visually): Fix subtle bugs in the fallback
code, revealed in presence of R2L characters, character
compositions, and display vectors. A better fix for Bug#16148.
* dispextern.h (struct composition_it): Correct a comment for the
'width' member.
2013-12-16 Paul Eggert <eggert@cs.ucla.edu>
* font.h (valid_font_driver) [!ENABLE_CHECKING]: Define a dummy.

5
src/dispextern.h
View file

@ -2190,9 +2190,8 @@ struct composition_it
int nchars, nbytes;
/* Indices of the glyphs for the current grapheme cluster. */
int from, to;
/* Width of the current grapheme cluster in units of pixels on a
graphic display and in units of canonical characters on a
terminal display. */
/* Width of the current grapheme cluster in units of columns it will
occupy on display; see CHAR_WIDTH. */
int width;
};

81
src/xdisp.c
View file

@ -20589,23 +20589,37 @@ Value is the new character position of point. */)
SET_TEXT_POS (pt, PT, PT_BYTE);
start_display (&it, w, pt);
if ((it.cmp_it.id < 0
&& it.method == GET_FROM_STRING
&& it.area == TEXT_AREA
&& it.string_from_display_prop_p
&& (it.sp > 0 && it.stack[it.sp - 1].method == GET_FROM_BUFFER))
|| it.method == GET_FROM_DISPLAY_VECTOR)
if (it.cmp_it.id < 0
&& it.method == GET_FROM_STRING
&& it.area == TEXT_AREA
&& it.string_from_display_prop_p
&& (it.sp > 0 && it.stack[it.sp - 1].method == GET_FROM_BUFFER))
overshoot_expected = true;
/* Find the X coordinate of point. We start from the beginning
of this or previous line to make sure we are before point in
the logical order (since the move_it_* functions can only
move forward). */
reseat:
reseat_at_previous_visible_line_start (&it);
it.current_x = it.hpos = it.current_y = it.vpos = 0;
if (IT_CHARPOS (it) != PT)
move_it_to (&it, overshoot_expected ? PT - 1 : PT,
-1, -1, -1, MOVE_TO_POS);
{
move_it_to (&it, overshoot_expected ? PT - 1 : PT,
-1, -1, -1, MOVE_TO_POS);
/* If we missed point because the character there is
displayed out of a display vector that has more than one
glyph, retry expecting overshoot. */
if (it.method == GET_FROM_DISPLAY_VECTOR
&& it.current.dpvec_index > 0
&& !overshoot_expected)
{
overshoot_expected = true;
goto reseat;
}
else if (IT_CHARPOS (it) != PT && !overshoot_expected)
move_it_in_display_line (&it, PT, -1, MOVE_TO_POS);
}
pt_x = it.current_x;
pt_vpos = it.vpos;
if (dir > 0 || overshoot_expected)
@ -20634,9 +20648,9 @@ Value is the new character position of point. */)
else if (pixel_width <= 0)
pixel_width = 1;
/* If there's a display string at point, we are actually at the
glyph to the left of point, so we need to correct the X
coordinate. */
/* If there's a display string (or something similar) at point,
we are actually at the glyph to the left of point, so we need
to correct the X coordinate. */
if (overshoot_expected)
{
if (it.bidi_p)
@ -20699,15 +20713,37 @@ Value is the new character position of point. */)
character at point. */
if (FRAME_WINDOW_P (it.f) && dir < 0)
{
struct text_pos new_pos = it.current.pos;
struct text_pos new_pos;
enum move_it_result rc = MOVE_X_REACHED;
if (it.current_x == 0)
get_next_display_element (&it);
if (it.what == IT_COMPOSITION)
{
new_pos.charpos = it.cmp_it.charpos;
new_pos.bytepos = -1;
}
else
new_pos = it.current.pos;
while (it.current_x + it.pixel_width <= target_x
&& rc == MOVE_X_REACHED)
{
int new_x = it.current_x + it.pixel_width;
new_pos = it.current.pos;
/* For composed characters, we want the position of the
first character in the grapheme cluster (usually, the
composition's base character), whereas it.current
might give us the position of the _last_ one, e.g. if
the composition is rendered in reverse due to bidi
reordering. */
if (it.what == IT_COMPOSITION)
{
new_pos.charpos = it.cmp_it.charpos;
new_pos.bytepos = -1;
}
else
new_pos = it.current.pos;
if (new_x == it.current_x)
new_x++;
rc = move_it_in_display_line_to (&it, ZV, new_x,
@ -20715,21 +20751,10 @@ Value is the new character position of point. */)
if (ITERATOR_AT_END_OF_LINE_P (&it) && !target_is_eol_p)
break;
}
/* If we ended up on a composed character inside
bidi-reordered text (e.g., Hebrew text with diacritics),
the iterator gives us the buffer position of the last (in
logical order) character of the composed grapheme cluster,
which is not what we want. So we cheat: we compute the
character position of the character that follows (in the
logical order) the one where the above loop stopped. That
character will appear on display to the left of point. */
if (it.bidi_p
&& it.bidi_it.scan_dir == -1
&& new_pos.charpos - IT_CHARPOS (it) > 1)
{
new_pos.charpos = IT_CHARPOS (it) + 1;
new_pos.bytepos = CHAR_TO_BYTE (new_pos.charpos);
}
/* The previous position we saw in the loop is the one we
want. */
if (new_pos.bytepos == -1)
new_pos.bytepos = CHAR_TO_BYTE (new_pos.charpos);
it.current.pos = new_pos;
}
else