Fix bug #6671 with recentering and other scrolling problems.
src/xdisp.c (SCROLL_LIMIT): New macro. (try_scrolling): Use it when setting scroll_limit. Limit scrolling to 100 screen lines. (redisplay_window): Even when falling back on "recentering", position point in the window according to scroll-conservatively, scroll-margin, and scroll-*-aggressively variables. (try_scrolling): When point is above the window, allow searching as far as scroll_max, or one screenful, to compute vertical distance from PT to the scroll margin position. This prevents try_scrolling from unnecessarily failing when scroll-conservatively is set to a value slightly larger than the window height. Clean up the case of PT below the margin at bottom of window: scroll_max can no longer be INT_MAX. When aggressive scrolling is in use, don't let point enter the opposite scroll margin as result of the scroll. (syms_of_xdisp) <scroll-conservatively>: Document the threshold of 100 lines for never-recentering scrolling. doc/emacs/display.texi (Auto Scrolling): Document the limit of 100 lines for never-recentering scrolling with `scroll-conservatively'.
This commit is contained in:
Eli Zaretskii
commit
63696a737c
4 changed files with 163 additions and 32 deletions
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@ -1,3 +1,9 @@
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2011-03-30 Eli Zaretskii <eliz@gnu.org>
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* display.texi (Auto Scrolling): Document the limit of 100 lines
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for never-recentering scrolling with `scroll-conservatively'.
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(Bug#6671)
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2011-03-12 Eli Zaretskii <eliz@gnu.org>
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* msdog.texi (Windows HOME): Fix the wording to clarify how Emacs sets
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@ -183,7 +183,20 @@ visible portion of the text.
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if you set @code{scroll-conservatively} to a small number @var{n},
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then if you move point just a little off the screen (less than @var{n}
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lines), Emacs scrolls the text just far enough to bring point back on
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screen. By default, @code{scroll-conservatively} is@tie{}0.
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screen. By default, @code{scroll-conservatively} is@tie{}0. If you
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set @code{scroll-conservatively} to a large number (larger than 100),
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Emacs will never center point as result of scrolling, even if point
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moves far away from the text previously displayed in the window. With
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such a large value, Emacs will always scroll text just enough for
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bringing point into view, so point will end up at the top or bottom of
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the window, depending on the scroll direction.
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@vindex scroll-step
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The variable @code{scroll-step} determines how many lines to scroll
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the window when point moves off the screen. If moving by that number
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of lines fails to bring point back into view, point is centered
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instead. The default value is zero, which causes point to always be
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centered after scrolling.
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@cindex aggressive scrolling
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@vindex scroll-up-aggressively
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@ -204,6 +217,9 @@ down. The value specifies how far point should be placed from the
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bottom of the window; thus, as with @code{scroll-up-aggressively}, a
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larger value is more aggressive.
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These two variables are ignored if either @code{scroll-step} or
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@code{scroll-conservatively} are set to a non-zero value.
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@vindex scroll-margin
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The variable @code{scroll-margin} restricts how close point can come
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to the top or bottom of a window. Its value is a number of screen
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@ -1,3 +1,29 @@
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2011-03-31 Eli Zaretskii <eliz@gnu.org>
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* xdisp.c (SCROLL_LIMIT): New macro.
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(try_scrolling): Use it when setting scroll_limit. Limit
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scrolling to 100 screen lines.
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(redisplay_window): Even when falling back on "recentering",
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position point in the window according to scroll-conservatively,
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scroll-margin, and scroll-*-aggressively variables. (Bug#6671)
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(try_scrolling): When point is above the window, allow searching
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as far as scroll_max, or one screenful, to compute vertical
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distance from PT to the scroll margin position. This prevents
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try_scrolling from unnecessarily failing when
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scroll-conservatively is set to a value slightly larger than the
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window height. Clean up the case of PT below the margin at bottom
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of window: scroll_max can no longer be INT_MAX. When aggressive
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scrolling is in use, don't let point enter the opposite scroll
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margin as result of the scroll.
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(syms_of_xdisp) <scroll-conservatively>: Document the
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threshold of 100 lines for never-recentering scrolling.
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2011-03-26 Eli Zaretskii <eliz@gnu.org>
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* xdisp.c (redisplay_window): Don't check buffer's clip_changed
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flag as a prerequisite for invoking try_scrolling. (Bug#6671)
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2011-03-31 Juanma Barranquero <lekktu@gmail.com>
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* dispextern.h (move_it_by_lines):
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@ -184,11 +210,6 @@
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* s/usg5-4-common.h (SIGTYPE): Remove definition.
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* s/template.h (SIGTYPE): Remove commented out definition.
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2011-03-26 Eli Zaretskii <eliz@gnu.org>
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* xdisp.c (redisplay_window): Don't check buffer's clip_changed
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flag as a prerequisite for invoking try_scrolling. (Bug#6671)
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2011-03-26 Juanma Barranquero <lekktu@gmail.com>
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* w32.c (read_unc_volume): Use parameter `henum', instead of
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140
src/xdisp.c
140
src/xdisp.c
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@ -12992,6 +12992,12 @@ enum
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SCROLLING_NEED_LARGER_MATRICES
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};
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/* If scroll-conservatively is more than this, never recenter.
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If you change this, don't forget to update the doc string of
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`scroll-conservatively' and the Emacs manual. */
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#define SCROLL_LIMIT 100
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static int
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try_scrolling (Lisp_Object window, int just_this_one_p,
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EMACS_INT arg_scroll_conservatively, EMACS_INT scroll_step,
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@ -13005,7 +13011,8 @@ try_scrolling (Lisp_Object window, int just_this_one_p,
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int dy = 0, amount_to_scroll = 0, scroll_down_p = 0;
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int extra_scroll_margin_lines = last_line_misfit ? 1 : 0;
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Lisp_Object aggressive;
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int scroll_limit = INT_MAX / FRAME_LINE_HEIGHT (f);
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/* We will never try scrolling more than this number of lines. */
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int scroll_limit = SCROLL_LIMIT;
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#if GLYPH_DEBUG
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debug_method_add (w, "try_scrolling");
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@ -13021,14 +13028,14 @@ try_scrolling (Lisp_Object window, int just_this_one_p,
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else
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this_scroll_margin = 0;
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/* Force arg_scroll_conservatively to have a reasonable value, to avoid
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overflow while computing how much to scroll. Note that the user
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can supply scroll-conservatively equal to `most-positive-fixnum',
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which can be larger than INT_MAX. */
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/* Force arg_scroll_conservatively to have a reasonable value, to
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avoid scrolling too far away with slow move_it_* functions. Note
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that the user can supply scroll-conservatively equal to
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`most-positive-fixnum', which can be larger than INT_MAX. */
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if (arg_scroll_conservatively > scroll_limit)
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{
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arg_scroll_conservatively = scroll_limit;
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scroll_max = INT_MAX;
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arg_scroll_conservatively = scroll_limit + 1;
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scroll_max = scroll_limit * FRAME_LINE_HEIGHT (f);
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}
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else if (scroll_step || arg_scroll_conservatively || temp_scroll_step)
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/* Compute how much we should try to scroll maximally to bring
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@ -13065,13 +13072,10 @@ try_scrolling (Lisp_Object window, int just_this_one_p,
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/* Compute how many pixels below window bottom to stop searching
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for PT. This avoids costly search for PT that is far away if
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the user limited scrolling by a small number of lines, but
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always finds PT if arg_scroll_conservatively is set to a large
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always finds PT if scroll_conservatively is set to a large
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number, such as most-positive-fixnum. */
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int slack = max (scroll_max, 10 * FRAME_LINE_HEIGHT (f));
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int y_to_move =
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slack >= INT_MAX - it.last_visible_y
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? INT_MAX
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: it.last_visible_y + slack;
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int y_to_move = it.last_visible_y + slack;
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/* Compute the distance from the scroll margin to PT or to
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the scroll limit, whichever comes first. This should
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@ -13110,6 +13114,10 @@ try_scrolling (Lisp_Object window, int just_this_one_p,
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amount_to_scroll = float_amount;
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if (amount_to_scroll == 0 && float_amount > 0)
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amount_to_scroll = 1;
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/* Don't let point enter the scroll margin near top of
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the window. */
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if (amount_to_scroll > height - 2*this_scroll_margin + dy)
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amount_to_scroll = height - 2*this_scroll_margin + dy;
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}
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}
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@ -13117,12 +13125,12 @@ try_scrolling (Lisp_Object window, int just_this_one_p,
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return SCROLLING_FAILED;
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start_display (&it, w, startp);
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if (scroll_max < INT_MAX)
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if (arg_scroll_conservatively <= scroll_limit)
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move_it_vertically (&it, amount_to_scroll);
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else
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{
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/* Extra precision for users who set scroll-conservatively
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to most-positive-fixnum: make sure the amount we scroll
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to a large number: make sure the amount we scroll
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the window start is never less than amount_to_scroll,
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which was computed as distance from window bottom to
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point. This matters when lines at window top and lines
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@ -13160,16 +13168,19 @@ try_scrolling (Lisp_Object window, int just_this_one_p,
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{
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/* Point is in the scroll margin at the top of the window or
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above what is displayed in the window. */
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int y0;
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int y0, y_to_move;
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/* Compute the vertical distance from PT to the scroll
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margin position. Give up if distance is greater than
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scroll_max. */
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margin position. Move as far as scroll_max allows, or
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one screenful, or 10 screen lines, whichever is largest.
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Give up if distance is greater than scroll_max. */
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SET_TEXT_POS (pos, PT, PT_BYTE);
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start_display (&it, w, pos);
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y0 = it.current_y;
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y_to_move = max (it.last_visible_y,
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max (scroll_max, 10 * FRAME_LINE_HEIGHT (f)));
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move_it_to (&it, CHARPOS (scroll_margin_pos), 0,
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it.last_visible_y, -1,
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y_to_move, -1,
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MOVE_TO_POS | MOVE_TO_X | MOVE_TO_Y);
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dy = it.current_y - y0;
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if (dy > scroll_max)
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@ -13179,8 +13190,8 @@ try_scrolling (Lisp_Object window, int just_this_one_p,
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start_display (&it, w, startp);
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if (arg_scroll_conservatively)
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amount_to_scroll
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= max (dy, FRAME_LINE_HEIGHT (f) * max (scroll_step, temp_scroll_step));
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amount_to_scroll = max (dy, FRAME_LINE_HEIGHT (f) *
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max (scroll_step, temp_scroll_step));
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else if (scroll_step || temp_scroll_step)
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amount_to_scroll = scroll_max;
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else
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@ -13193,6 +13204,12 @@ try_scrolling (Lisp_Object window, int just_this_one_p,
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amount_to_scroll = float_amount;
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if (amount_to_scroll == 0 && float_amount > 0)
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amount_to_scroll = 1;
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amount_to_scroll -=
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this_scroll_margin - dy - FRAME_LINE_HEIGHT (f);
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/* Don't let point enter the scroll margin near
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bottom of the window. */
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if (amount_to_scroll > height - 2*this_scroll_margin + dy)
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amount_to_scroll = height - 2*this_scroll_margin + dy;
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}
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}
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@ -14190,11 +14207,10 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
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}
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}
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/* Finally, just choose place to start which centers point */
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/* Finally, just choose a place to start which positions point
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according to user preferences. */
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recenter:
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if (centering_position < 0)
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centering_position = window_box_height (w) / 2;
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#if GLYPH_DEBUG
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debug_method_add (w, "recenter");
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@ -14206,10 +14222,77 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
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if (!buffer_unchanged_p)
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w->base_line_number = Qnil;
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/* Move backward half the height of the window. */
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/* Determine the window start relative to point. */
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init_iterator (&it, w, PT, PT_BYTE, NULL, DEFAULT_FACE_ID);
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it.current_y = it.last_visible_y;
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if (centering_position < 0)
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{
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int margin =
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scroll_margin > 0
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? min (scroll_margin, WINDOW_TOTAL_LINES (w) / 4)
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: 0;
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EMACS_INT margin_pos = CHARPOS (startp);
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int scrolling_up;
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Lisp_Object aggressive;
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/* If there is a scroll margin at the top of the window, find
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its character position. */
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if (margin)
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{
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struct it it1;
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start_display (&it1, w, startp);
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move_it_vertically (&it1, margin);
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margin_pos = IT_CHARPOS (it1);
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}
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scrolling_up = PT > margin_pos;
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aggressive =
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scrolling_up
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? BVAR (current_buffer, scroll_up_aggressively)
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: BVAR (current_buffer, scroll_down_aggressively);
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if (!MINI_WINDOW_P (w)
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&& (scroll_conservatively > SCROLL_LIMIT || NUMBERP (aggressive)))
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{
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int pt_offset = 0;
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/* Setting scroll-conservatively overrides
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scroll-*-aggressively. */
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if (!scroll_conservatively && NUMBERP (aggressive))
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{
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double float_amount = XFLOATINT (aggressive);
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pt_offset = float_amount * WINDOW_BOX_TEXT_HEIGHT (w);
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if (pt_offset == 0 && float_amount > 0)
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pt_offset = 1;
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if (pt_offset)
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margin -= 1;
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}
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/* Compute how much to move the window start backward from
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point so that point will be displayed where the user
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wants it. */
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if (scrolling_up)
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{
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centering_position = it.last_visible_y;
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if (pt_offset)
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centering_position -= pt_offset;
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centering_position -=
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FRAME_LINE_HEIGHT (f) * (1 + margin + (last_line_misfit != 0));
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/* Don't let point enter the scroll margin near top of
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the window. */
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if (centering_position < margin * FRAME_LINE_HEIGHT (f))
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centering_position = margin * FRAME_LINE_HEIGHT (f);
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}
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else
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centering_position = margin * FRAME_LINE_HEIGHT (f) + pt_offset;
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}
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else
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/* Set the window start half the height of the window backward
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from point. */
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centering_position = window_box_height (w) / 2;
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}
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move_it_vertically_backward (&it, centering_position);
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xassert (IT_CHARPOS (it) >= BEGV);
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/* The function move_it_vertically_backward may move over more
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@ -14226,8 +14309,9 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
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it.current_x = it.hpos = 0;
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/* Set startp here explicitly in case that helps avoid an infinite loop
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in case the window-scroll-functions functions get errors. */
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/* Set the window start position here explicitly, to avoid an
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infinite loop in case the functions in window-scroll-functions
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get errors. */
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set_marker_both (w->start, Qnil, IT_CHARPOS (it), IT_BYTEPOS (it));
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/* Run scroll hooks. */
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@ -26504,6 +26588,10 @@ If point moves off-screen, redisplay will scroll by up to
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onto the screen again. If that cannot be done, then redisplay
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recenters point as usual.
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If the value is greater than 100, redisplay will never recenter point,
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but will always scroll just enough text to bring point into view, even
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if you move far away.
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A value of zero means always recenter point if it moves off screen. */);
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scroll_conservatively = 0;
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Add table
Reference in a new issue