Commit 9583ec36 authored by Eli Zaretskii's avatar Eli Zaretskii

Fix bug #14567 with jumpy scrolling of tall images.

 src/xdisp.c (Fline_pixel_height): New function, required for solving
 bug #14567.

 lisp/simple.el (line-move-partial): Don't jump to the next screen
 line as soon as it becomes visible.  Instead, continue enlarging
 the vscroll until the portion of a tall screen line that's left on
 display is about the height of the frame's default font.
parent d1ad37b2
2013-06-15 Eli Zaretskii <eliz@gnu.org>
* simple.el (line-move-partial): Don't jump to the next screen
line as soon as it becomes visible. Instead, continue enlarging
the vscroll until the portion of a tall screen line that's left on
display is about the height of the frame's default font.
(Bug#14567)
2013-06-15 Glenn Morris <rgm@gnu.org>
* vc/vc-dispatcher.el (vc-compilation-mode): Avoid making
......@@ -4738,42 +4738,62 @@ lines."
(vpos (nth 1 lh))
(ypos (nth 2 lh))
(rbot (nth 3 lh))
(this-lh (window-line-height))
(this-height (nth 0 this-lh))
(this-ypos (nth 2 this-lh))
(fch (frame-char-height))
py vs)
(when (or (null lh)
(>= rbot (frame-char-height))
(<= ypos (- (frame-char-height))))
(>= rbot fch)
(<= ypos (- fch))
(null this-lh)
(<= this-ypos (- fch)))
(unless lh
(let ((wend (pos-visible-in-window-p t nil t)))
(setq rbot (nth 3 wend)
vpos (nth 5 wend))))
(unless this-lh
(let ((wstart (pos-visible-in-window-p nil nil t)))
(setq this-ypos (nth 2 wstart)
this-height (nth 4 wstart))))
(setq py
(or (nth 1 this-lh)
(let ((ppos (posn-at-point)))
(cdr (or (posn-actual-col-row ppos)
(posn-col-row ppos))))))
(cond
;; If last line of window is fully visible, move forward.
((or (null rbot) (= rbot 0))
;; If last line of window is fully visible, and vscrolling
;; more would make this line invisible, move forward.
((and (or (< (setq vs (window-vscroll nil t)) fch)
(null this-height)
(<= this-height fch))
(or (null rbot) (= rbot 0)))
nil)
;; If cursor is not in the bottom scroll margin, move forward.
((and (> vpos 0)
(< (setq py
(or (nth 1 (window-line-height))
(let ((ppos (posn-at-point)))
(cdr (or (posn-actual-col-row ppos)
(posn-col-row ppos))))))
;; If cursor is not in the bottom scroll margin, and the
;; current line is is not too tall, move forward.
((and (or (null this-height) (<= this-height fch))
vpos
(> vpos 0)
(< py
(min (- (window-text-height) scroll-margin 1) (1- vpos))))
nil)
;; When already vscrolled, we vscroll some more if we can,
;; or clear vscroll and move forward at end of tall image.
((> (setq vs (window-vscroll nil t)) 0)
(when (> rbot 0)
(set-window-vscroll nil (+ vs (min rbot (frame-char-height))) t)))
((> vs 0)
(when (or (and rbot (> rbot 0))
(and this-height (> this-height fch)))
(set-window-vscroll nil (+ vs fch) t)))
;; If cursor just entered the bottom scroll margin, move forward,
;; but also vscroll one line so redisplay won't recenter.
((and (> vpos 0)
((and vpos
(> vpos 0)
(= py (min (- (window-text-height) scroll-margin 1)
(1- vpos))))
(set-window-vscroll nil (frame-char-height) t)
(line-move-1 arg noerror to-end)
t)
;; If there are lines above the last line, scroll-up one line.
((> vpos 0)
((and vpos (> vpos 0))
(scroll-up 1)
t)
;; Finally, start vscroll.
......@@ -4808,7 +4828,14 @@ lines."
;; display-based motion doesn't make sense (because each
;; logical line occupies exactly one screen line).
(not (> (window-hscroll) 0)))
(line-move-visual arg noerror)
(prog1 (line-move-visual arg noerror)
;; If we moved into a tall line, set vscroll to make
;; scrolling through tall images more smooth.
(let ((lh (line-pixel-height)))
(if (and (< arg 0)
(< (point) (window-start))
(> lh (frame-char-height)))
(set-window-vscroll nil (- lh (frame-char-height)) t))))
(line-move-1 arg noerror to-end)))))
;; Display-based alternative to line-move-1.
......
2013-06-15 Eli Zaretskii <eliz@gnu.org>
* xdisp.c (Fline_pixel_height): New function, required for solving
bug #14567.
2013-06-15 Paul Eggert <eggert@cs.ucla.edu>
* fns.c (Fcopy_sequence): Simplify XTYPE calculation.
......
......@@ -1217,6 +1217,24 @@ line_bottom_y (struct it *it)
return line_top_y + line_height;
}
DEFUN ("line-pixel-height", Fline_pixel_height,
Sline_pixel_height, 0, 0, 0,
doc: /* Return height in pixels of text line in the selected window.
Value is the height in pixels of the line at point. */)
(void)
{
struct it it;
struct text_pos pt;
struct window *w = XWINDOW (selected_window);
SET_TEXT_POS (pt, PT, PT_BYTE);
start_display (&it, w, pt);
it.vpos = it.current_y = 0;
last_height = 0;
return make_number (line_bottom_y (&it));
}
/* Subroutine of pos_visible_p below. Extracts a display string, if
any, from the display spec given as its argument. */
static Lisp_Object
......@@ -28691,6 +28709,7 @@ syms_of_xdisp (void)
defsubr (&Stool_bar_lines_needed);
defsubr (&Slookup_image_map);
#endif
defsubr (&Sline_pixel_height);
defsubr (&Sformat_mode_line);
defsubr (&Sinvisible_p);
defsubr (&Scurrent_bidi_paragraph_direction);
......
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