diff options
Diffstat (limited to 'src/window.c')
| -rw-r--r-- | src/window.c | 53 |
1 files changed, 36 insertions, 17 deletions
diff --git a/src/window.c b/src/window.c index bc3f488f37f..95690443f8e 100644 --- a/src/window.c +++ b/src/window.c @@ -4790,6 +4790,36 @@ window_scroll (Lisp_Object window, EMACS_INT n, bool whole, bool noerror) XWINDOW (window)->window_end_valid = false; } +/* Compute scroll margin for WINDOW. + We scroll when point is within this distance from the top or bottom + of the window. The result is measured in lines or in pixels + depending on the second parameter. */ +int +window_scroll_margin (struct window *window, enum margin_unit unit) +{ + if (scroll_margin > 0) + { + int frame_line_height = default_line_pixel_height (window); + int window_lines = window_box_height (window) / frame_line_height; + + double ratio = 0.25; + if (FLOATP (Vmaximum_scroll_margin)) + { + ratio = XFLOAT_DATA (Vmaximum_scroll_margin); + ratio = max (0.0, ratio); + ratio = min (ratio, 0.5); + } + int max_margin = min ((window_lines - 1)/2, + (int) (window_lines * ratio)); + int margin = clip_to_bounds (0, scroll_margin, max_margin); + return (unit == MARGIN_IN_PIXELS) + ? margin * frame_line_height + : margin; + } + else + return 0; +} + /* Implementation of window_scroll that works based on pixel line heights. See the comment of window_scroll for parameter @@ -4806,7 +4836,6 @@ window_scroll_pixel_based (Lisp_Object window, int n, bool whole, bool noerror) bool vscrolled = false; int x, y, rtop, rbot, rowh, vpos; void *itdata = NULL; - int window_total_lines; int frame_line_height = default_line_pixel_height (w); bool adjust_old_pointm = !NILP (Fequal (Fwindow_point (window), Fwindow_old_point (window))); @@ -5062,12 +5091,7 @@ window_scroll_pixel_based (Lisp_Object window, int n, bool whole, bool noerror) /* Move PT out of scroll margins. This code wants current_y to be zero at the window start position even if there is a header line. */ - window_total_lines - = w->total_lines * WINDOW_FRAME_LINE_HEIGHT (w) / frame_line_height; - this_scroll_margin = max (0, scroll_margin); - this_scroll_margin - = min (this_scroll_margin, window_total_lines / 4); - this_scroll_margin *= frame_line_height; + this_scroll_margin = window_scroll_margin (w, MARGIN_IN_PIXELS); if (n > 0) { @@ -5123,7 +5147,7 @@ window_scroll_pixel_based (Lisp_Object window, int n, bool whole, bool noerror) in the scroll margin at the bottom. */ move_it_to (&it, PT, -1, (it.last_visible_y - WINDOW_HEADER_LINE_HEIGHT (w) - - this_scroll_margin - 1), + - partial_line_height (&it) - this_scroll_margin - 1), -1, MOVE_TO_POS | MOVE_TO_Y); @@ -5290,9 +5314,7 @@ window_scroll_line_based (Lisp_Object window, int n, bool whole, bool noerror) if (pos < ZV) { - /* Don't use a scroll margin that is negative or too large. */ - int this_scroll_margin = - max (0, min (scroll_margin, w->total_lines / 4)); + int this_scroll_margin = window_scroll_margin (w, MARGIN_IN_LINES); set_marker_restricted_both (w->start, w->contents, pos, pos_byte); w->start_at_line_beg = !NILP (bolp); @@ -5722,8 +5744,7 @@ and redisplay normally--don't erase and redraw the frame. */) /* Do this after making BUF current in case scroll_margin is buffer-local. */ - this_scroll_margin - = max (0, min (scroll_margin, w->total_lines / 4)); + this_scroll_margin = window_scroll_margin (w, MARGIN_IN_LINES); /* Don't use redisplay code for initial frames, as the necessary data structures might not be set up yet then. */ @@ -5962,10 +5983,6 @@ from the top of the window. */) lines = displayed_window_lines (w); -#if false - this_scroll_margin = max (0, min (scroll_margin, lines / 4)); -#endif - if (NILP (arg)) XSETFASTINT (arg, lines / 2); else @@ -5981,6 +5998,8 @@ from the top of the window. */) it is probably better not to install it. However, it is here inside #if false so as not to lose it. -- rms. */ + this_scroll_margin = window_scroll_margin (w, MARGIN_IN_LINES); + /* Don't let it get into the margin at either top or bottom. */ iarg = max (iarg, this_scroll_margin); iarg = min (iarg, lines - this_scroll_margin - 1); |