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Fix bug #6671 with point position in the window when scrolling far away.

Browse source 
src/xdisp.c (redisplay_window): Don't check buffer's clip_changed
 flag as a prerequisite for invoking try_scrolling.
 (try_scrolling): Limit scrolling to 100 screen lines.
 (SCROLL_LIMIT): New macro.
 (try_scrolling): Use it when setting scroll_limit.
 (redisplay_window): Even when falling back on "recentering",
 position point in the window according to scroll-conservatively,
 scroll-margin, and scroll-*-aggressively variables.
This commit is contained in:
Eli Zaretskii 2011-03-26 20:31:36 +02:00
parent 5d9bd9764f
commit 06b6bbb578
2 changed files with 67 additions and 7 deletions
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5
src/ChangeLog
View file

@ -3,6 +3,11 @@
* xdisp.c (redisplay_window): Don't check buffer's clip_changed
flag as a prerequisite for invoking try_scrolling. (Bug#6671)
(try_scrolling): Limit scrolling to 100 screen lines.
(SCROLL_LIMIT): New macro.
(try_scrolling): Use it when setting scroll_limit.
(redisplay_window): Even when falling back on "recentering",
position point in the window according to scroll-conservatively,
scroll-margin, and scroll-*-aggressively variables. (Bug#6671)
2011-03-26 Juanma Barranquero <lekktu@gmail.com>

69
src/xdisp.c
View file

@ -13003,6 +13003,9 @@ enum
SCROLLING_NEED_LARGER_MATRICES
};
/* If scroll-conservatively is more than this, never recenter. */
#define SCROLL_LIMIT 100
static int
try_scrolling (Lisp_Object window, int just_this_one_p,
EMACS_INT arg_scroll_conservatively, EMACS_INT scroll_step,
@ -13017,7 +13020,7 @@ try_scrolling (Lisp_Object window, int just_this_one_p,
int extra_scroll_margin_lines = last_line_misfit ? 1 : 0;
Lisp_Object aggressive;
/* We will never try scrolling more than this number of lines. */
int scroll_limit = 100;
int scroll_limit = SCROLL_LIMIT;
#if GLYPH_DEBUG
debug_method_add (w, "try_scrolling");
@ -14202,11 +14205,10 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
}
}
/* Finally, just choose place to start which centers point */
/* Finally, just choose a place to start which positions point
according to user preferences. */
recenter:
if (centering_position < 0)
centering_position = window_box_height (w) / 2;
#if GLYPH_DEBUG
debug_method_add (w, "recenter");
@ -14218,10 +14220,62 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
if (!buffer_unchanged_p)
w->base_line_number = Qnil;
/* Move backward half the height of the window. */
/* Determine the window start relative to point. */
init_iterator (&it, w, PT, PT_BYTE, NULL, DEFAULT_FACE_ID);
it.current_y = it.last_visible_y;
if (centering_position < 0)
{
int margin =
scroll_margin > 0
? min (scroll_margin, WINDOW_TOTAL_LINES (w) / 4)
: 0;
int scrolling_up = PT > CHARPOS (startp) + margin;
Lisp_Object aggressive =
scrolling_up
? BVAR (current_buffer, scroll_up_aggressively)
: BVAR (current_buffer, scroll_down_aggressively);
if (!MINI_WINDOW_P (w)
&& scroll_conservatively > SCROLL_LIMIT || NUMBERP (aggressive))
{
int pt_offset = 0;
/* Setting scroll-conservatively overrides
scroll-*-aggressively. */
if (!scroll_conservatively && NUMBERP (aggressive))
{
double float_amount = XFLOATINT (aggressive);
pt_offset = float_amount * WINDOW_BOX_TEXT_HEIGHT (w);
if (pt_offset == 0 && float_amount > 0)
pt_offset = 1;
if (pt_offset)
margin -= 1;
}
/* Compute how much to move the window start backward from
point so that point will be displayed where the user
wants it. */
if (scrolling_up)
{
centering_position = it.last_visible_y;
if (pt_offset)
centering_position -= pt_offset;
centering_position -=
FRAME_LINE_HEIGHT (f) * (1 + margin + (last_line_misfit != 0));
/* Don't let point enter the scroll margin near top of
the window. */
if (centering_position < margin * FRAME_LINE_HEIGHT (f))
centering_position = margin * FRAME_LINE_HEIGHT (f);
}
else
centering_position = margin * FRAME_LINE_HEIGHT (f) + pt_offset;
}
else
/* Move backward from point half the height of the window. */
centering_position = window_box_height (w) / 2;
}
move_it_vertically_backward (&it, centering_position);
xassert (IT_CHARPOS (it) >= BEGV);
/* The function move_it_vertically_backward may move over more
@ -14238,8 +14292,9 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
it.current_x = it.hpos = 0;
/* Set startp here explicitly in case that helps avoid an infinite loop
in case the window-scroll-functions functions get errors. */
/* Set the window start position here explicitly, to avoid an
infinite loop in case the functions in window-scroll-functions
get errors. */
set_marker_both (w->start, Qnil, IT_CHARPOS (it), IT_BYTEPOS (it));
/* Run scroll hooks. */