patch 8.2.4673: redrawing a split window is slow when using CTRL-F and CTRL-B
Problem: Redrawing a vertically split window is slow when using CTRL-F and
CTRL-B.
Solution: When deciding on USE_REDRAW bail out if scrolling more than three
lines. (issue #8002)
diff --git a/src/screen.c b/src/screen.c
index 3713f49..7caf299 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -3707,7 +3707,15 @@
*/
result_empty = (row + line_count >= end);
if (wp != NULL && wp->w_width != Columns && *T_CSV == NUL)
+ {
+ // Avoid that lines are first cleared here and then redrawn, which
+ // results in many characters updated twice. This happens with CTRL-F
+ // in a vertically split window. With line-by-line scrolling
+ // USE_REDRAW should be faster.
+ if (line_count > 3)
+ return FAIL;
type = USE_REDRAW;
+ }
else if (can_clear(T_CD) && result_empty)
type = USE_T_CD;
else if (*T_CAL != NUL && (line_count > 1 || *T_AL == NUL))
@@ -3879,7 +3887,7 @@
int end,
int force, // even when line_count > p_ttyscroll
int clear_attr, // used for clearing lines
- win_T *wp UNUSED) // NULL or window to use width from
+ win_T *wp) // NULL or window to use width from
{
int j;
int i;
@@ -3934,7 +3942,15 @@
* 6. redraw the characters from ScreenLines[].
*/
if (wp != NULL && wp->w_width != Columns && *T_CSV == NUL)
+ {
+ // Avoid that lines are first cleared here and then redrawn, which
+ // results in many characters updated twice. This happens with CTRL-F
+ // in a vertically split window. With line-by-line scrolling
+ // USE_REDRAW should be faster.
+ if (line_count > 3)
+ return FAIL;
type = USE_REDRAW;
+ }
else if (can_clear(T_CD) && result_empty)
type = USE_T_CD;
else if (row == 0 && (