begin viewing scrollback buffer at the first line of output instead of at the start of the scrollback buffer

This issue has been discussed before:
https://bbs.archlinux.org/viewtopic.php?id=108640

Copy mode and “hardcopy -h” always begin at the start of the scrollback buffer.
If a user sets a large scrollback limit with little output, then copy mode and
the file written by “hardcopy -h” will begin with many blank lines before the
first line of output.

The attached patch limits the scrollback buffer traversal to begin at the first
line of output, instead of the beginning of the scrollback buffer.

Also, code for moving to %age of buffer is changed to use float division so
that two different rep_cnt will not jump to the same location, except for
buffers less than 100 lines. Previously, the computed line number is rounded
down to the nearest 100th due to integer division.

Bug: 49377

1 files changed, 5 insertions, 3 deletions

diff --git a/src/mark.c b/src/mark.c
index eed7675..663cd6e 100644
--- a/src/mark.c
+++ b/src/mark.c
@@ -686,7 +686,9 @@ static void MarkProcess(char **inbufp, size_t *inlenp)
 				rep_cnt = 0;
 			if (rep_cnt > 100)
 				rep_cnt = 100;
-			revto_line(markdata->left_mar, (rep_cnt * (fore->w_histheight + fore->w_height)) / 100,
+			revto_line(markdata->left_mar,
+				   fore->w_histheight - fore->w_scrollback_height +
+					   (int)(rep_cnt * (fore->w_scrollback_height + fore->w_height) / 100.0),
 				   (fore->w_height - 1) / 2);
 			break;
 		case 0201:
@@ -994,8 +996,8 @@ void revto_line(int tx, int ty, int line)
 		tx = 0;
 	else if (tx > fore->w_width - 1)
 		tx = fore->w_width - 1;
-	if (ty < 0)
-		ty = 0;
+	if (ty < fore->w_histheight - fore->w_scrollback_height)
+		ty = fore->w_histheight - fore->w_scrollback_height;
 	else if (ty > fore->w_histheight + fore->w_height - 1)
 		ty = fore->w_histheight + fore->w_height - 1;