+2012-11-06 Eli Zaretskii <eliz@gnu.org>
+
+ * xdisp.c (try_scrolling): Fix correction of aggressive-scroll
+ amount when the scroll margins are too large. When scrolling
+ backwards in the buffer, give up if cannot reach point or the
+ scroll margin within a reasonable number of screen lines. Fixes
+ point position in window under scroll-up/down-aggressively when
+ point is positioned many lines beyond the window top/bottom.
+ (Bug#12811)
+
2012-11-05 Eli Zaretskii <eliz@gnu.org>
* ralloc.c (relinquish): If real_morecore fails to return memory
if (NUMBERP (aggressive))
{
double float_amount = XFLOATINT (aggressive) * height;
- amount_to_scroll = float_amount;
- if (amount_to_scroll == 0 && float_amount > 0)
- amount_to_scroll = 1;
+ int aggressive_scroll = float_amount;
+ if (aggressive_scroll == 0 && float_amount > 0)
+ aggressive_scroll = 1;
/* Don't let point enter the scroll margin near top of
- the window. */
- if (amount_to_scroll > height - 2*this_scroll_margin + dy)
- amount_to_scroll = height - 2*this_scroll_margin + dy;
+ the window. This could happen if the value of
+ scroll_up_aggressively is too large and there are
+ non-zero margins, because scroll_up_aggressively
+ means put point that fraction of window height
+ _from_the_bottom_margin_. */
+ if (aggressive_scroll + 2*this_scroll_margin > height)
+ aggressive_scroll = height - 2*this_scroll_margin;
+ amount_to_scroll = dy + aggressive_scroll;
}
}
/* Compute the vertical distance from PT to the scroll
margin position. Move as far as scroll_max allows, or
one screenful, or 10 screen lines, whichever is largest.
- Give up if distance is greater than scroll_max. */
+ Give up if distance is greater than scroll_max or if we
+ didn't reach the scroll margin position. */
SET_TEXT_POS (pos, PT, PT_BYTE);
start_display (&it, w, pos);
y0 = it.current_y;
y_to_move, -1,
MOVE_TO_POS | MOVE_TO_X | MOVE_TO_Y);
dy = it.current_y - y0;
- if (dy > scroll_max)
+ if (dy > scroll_max
+ || IT_CHARPOS (it) < CHARPOS (scroll_margin_pos))
return SCROLLING_FAILED;
/* Compute new window start. */
if (NUMBERP (aggressive))
{
double float_amount = XFLOATINT (aggressive) * height;
- amount_to_scroll = float_amount;
- if (amount_to_scroll == 0 && float_amount > 0)
- amount_to_scroll = 1;
- amount_to_scroll -=
- this_scroll_margin - dy - FRAME_LINE_HEIGHT (f);
+ int aggressive_scroll = float_amount;
+ if (aggressive_scroll == 0 && float_amount > 0)
+ aggressive_scroll = 1;
/* Don't let point enter the scroll margin near
- bottom of the window. */
- if (amount_to_scroll > height - 2*this_scroll_margin + dy)
- amount_to_scroll = height - 2*this_scroll_margin + dy;
+ bottom of the window, if the value of
+ scroll_down_aggressively happens to be too
+ large. */
+ if (aggressive_scroll + 2*this_scroll_margin > height)
+ aggressive_scroll = height - 2*this_scroll_margin;
+ amount_to_scroll = dy + aggressive_scroll;
}
}