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Fix vertical-motion across the place where line-number width changes

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* src/indent.c (line_number_display_width): New function,
refactored from line-number width calculations in vertical-motion.
(Fvertical_motion): Call line_number_display_width when the width
of line-number display is needed.
(Fline_number_display_width): New defun.
(syms_of_indent): Defsubr it.

* doc/lispref/display.texi (Size of Displayed Text): Document
line-number-display-width.

* etc/NEWS: Mention line-number-display-width.

* lisp/simple.el (last--line-number-width): New internal variable.
(line-move-visual): Use it to adjust temporary-goal-column when
line-number display changes its width.
This commit is contained in:
Eli Zaretskii 2017-07-07 12:21:10 +03:00
parent 25bc391161
commit 4caf65d4de
4 changed files with 101 additions and 25 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

17
doc/lispref/display.texi
View file

@ -1980,6 +1980,23 @@ selected window. The value includes the line spacing of the line
(@pxref{Line Height}).
@end defun
When a buffer is displayed with line numbers (@pxref{Display Custom,,,
emacs, The GNU Emacs Manual}), it is sometimes useful to know the
width taken for displaying the line numbers. The following function
is for Lisp programs which need this information for layout
calculations.
@defun line-number-display-width &optional pixelwise
This function returns the width used for displaying the line numbers
in the selected window. Optional argument @var{pixelwise}, if
non-@code{nil}, means return the value in pixels; otherwise the value
is returned in column units of the font defined for the
@code{line-number} face. If line numbers are not displayed in the
selected window, the value is zero. Use @code{with-selected-window}
(@pxref{Selecting Windows}) if you need this information about another
window.
@end defun
@node Line Height
@section Line Height

4
etc/NEWS
View file

@ -420,6 +420,10 @@ line by putting the 'display-line-numbers-disable' text property or
overlay property on the first character of that screen line. This is
intended for add-on packages that need a finer control of the display.
Lisp programs that need to know how much screen estate is used up for
line-number display in a window can use the new function
'line-number-display-width'.
Linum mode and all similar packages are henceforth becoming obsolete.
Users and developers are encouraged to switch to this new feature
instead.

21
lisp/simple.el
View file

@ -5931,6 +5931,10 @@ columns by which window is scrolled from left margin.
When the `track-eol' feature is doing its job, the value is
`most-positive-fixnum'.")
(defvar last--line-number-width 0
"Last value of width used for displaying line numbers.
Used internally by `line-move-visual'.")
(defcustom line-move-ignore-invisible t
"Non-nil means commands that move by lines ignore invisible newlines.
When this option is non-nil, \\[next-line], \\[previous-line], \\[move-end-of-line], and \\[move-beginning-of-line] behave
@ -6201,6 +6205,7 @@ not vscroll."
If NOERROR, don't signal an error if we can't move that many lines."
(let ((opoint (point))
(hscroll (window-hscroll))
(lnum-width (line-number-display-width t))
target-hscroll)
;; Check if the previous command was a line-motion command, or if
;; we were called from some other command.
@ -6208,9 +6213,19 @@ If NOERROR, don't signal an error if we can't move that many lines."
(memq last-command `(next-line previous-line ,this-command)))
;; If so, there's no need to reset `temporary-goal-column',
;; but we may need to hscroll.
(if (or (/= (cdr temporary-goal-column) hscroll)
(> (cdr temporary-goal-column) 0))
(setq target-hscroll (cdr temporary-goal-column)))
(progn
(if (or (/= (cdr temporary-goal-column) hscroll)
(> (cdr temporary-goal-column) 0))
(setq target-hscroll (cdr temporary-goal-column)))
;; Update the COLUMN part of temporary-goal-column if the
;; line-number display changed its width since the last
;; time.
(setq temporary-goal-column
(cons (+ (car temporary-goal-column)
(/ (float (- lnum-width last--line-number-width))
(frame-char-width)))
(cdr temporary-goal-column)))
(setq last--line-number-width lnum-width))
;; Otherwise, we should reset `temporary-goal-column'.
(let ((posn (posn-at-point))
x-pos)

84
src/indent.c
View file

@ -1947,6 +1947,59 @@ vmotion (register ptrdiff_t from, register ptrdiff_t from_byte,
-1, hscroll, 0, w);
}
/* Return the width taken by line-number display in window W. */
static void
line_number_display_width (struct window *w, int *width, int *pixel_width)
{
if (NILP (Vdisplay_line_numbers))
{
*width = 0;
*pixel_width = 0;
}
else
{
struct it it;
struct text_pos wstart;
bool saved_restriction = false;
ptrdiff_t count = SPECPDL_INDEX ();
SET_TEXT_POS_FROM_MARKER (wstart, w->start);
void *itdata = bidi_shelve_cache ();
/* We must start from window's start point, but it could be
outside the accessible region. */
if (wstart.charpos < BEGV || wstart.charpos > ZV)
{
record_unwind_protect (save_restriction_restore,
save_restriction_save ());
Fwiden ();
saved_restriction = true;
}
start_display (&it, w, wstart);
move_it_by_lines (&it, 1);
*width = it.lnum_width;
*pixel_width = it.lnum_pixel_width;
if (saved_restriction)
unbind_to (count, Qnil);
bidi_unshelve_cache (itdata, 0);
}
}
DEFUN ("line-number-display-width", Fline_number_display_width,
Sline_number_display_width, 0, 1, 0,
doc: /* Return the width used for displaying line numbers in the selected window.
If optional argument PIXELWISE is non-nil, return the width in pixels,
otherwise return the width in columns of the face used to display
line numbers, `line-number'. */)
(Lisp_Object pixelwise)
{
int width, pixel_width;
line_number_display_width (XWINDOW (selected_window), &width, &pixel_width);
if (!NILP (pixelwise))
return make_number (pixel_width);
/* FIXME: The "+ 2" part knows that we add a blank on each side of
the line number when producing glyphs for display. */
return make_number (width + 2);
}
/* In window W (derived from WINDOW), return x coordinate for column
COL (derived from COLUMN). */
static int
@ -2073,30 +2126,10 @@ whether or not it is currently displayed in some window. */)
that's what normal window redisplay does. Otherwise C-n/C-p
will sometimes err by one column. */
int lnum_width = 0;
int lnum_pixel_width = 0;
if (!NILP (Vdisplay_line_numbers)
&& !EQ (Vdisplay_line_numbers, Qvisual))
{
struct text_pos wstart;
bool saved_restriction = false;
ptrdiff_t count1 = SPECPDL_INDEX ();
SET_TEXT_POS_FROM_MARKER (wstart, w->start);
itdata = bidi_shelve_cache ();
/* We must start from window's start point, but it could be
outside the accessible region. */
if (wstart.charpos < BEGV || wstart.charpos > ZV)
{
record_unwind_protect (save_restriction_restore,
save_restriction_save ());
Fwiden ();
saved_restriction = true;
}
start_display (&it, w, wstart);
move_it_by_lines (&it, 1);
lnum_width = it.lnum_width;
if (saved_restriction)
unbind_to (count1, Qnil);
bidi_unshelve_cache (itdata, 0);
}
line_number_display_width (w, &lnum_width, &lnum_pixel_width);
SET_TEXT_POS (pt, PT, PT_BYTE);
itdata = bidi_shelve_cache ();
start_display (&it, w, pt);
@ -2277,6 +2310,12 @@ whether or not it is currently displayed in some window. */)
an addition to the hscroll amount. */
if (lcols_given)
{
/* If we are displaying line numbers, we could cross the
line where the width of the line-number display changes,
in which case we need to fix up the pixel coordinate
accordingly. */
if (lnum_pixel_width > 0)
to_x += it.lnum_pixel_width - lnum_pixel_width;
move_it_in_display_line (&it, ZV, first_x + to_x, MOVE_TO_X);
/* If we find ourselves in the middle of an overlay string
which includes a newline after current string position,
@ -2322,6 +2361,7 @@ syms_of_indent (void)
defsubr (&Sindent_to);
defsubr (&Scurrent_column);
defsubr (&Smove_to_column);
defsubr (&Sline_number_display_width);
defsubr (&Svertical_motion);
defsubr (&Scompute_motion);
}