[hackers] [scroll] Only move bottom if it was scrolled out of the window || Jochen Sprickerhof

[git]

commit 4b23d03e3c8dcac58d48fc89c1bc84f5ce27b718
Author:     Jochen Sprickerhof <g...@jochen.sprickerhof.de>
AuthorDate: Fri Apr 17 22:47:19 2020 +0200
Commit:     Jochen Sprickerhof <g...@jochen.sprickerhof.de>
CommitDate: Fri Apr 17 22:49:18 2020 +0200

    Only move bottom if it was scrolled out of the window

diff --git a/scroll.c b/scroll.c
index 3219915..25bd3fc 100644
--- a/scroll.c
+++ b/scroll.c
@@ -314,16 +314,22 @@ scrollup(int n)
                write(STDOUT_FILENO, scrollend->buf + 1, scrollend->size - 1);
        else
                write(STDOUT_FILENO, scrollend->buf, scrollend->size);
-       bottom = TAILQ_NEXT(bottom, entries);
+       if ( x + n >= ws.ws_row)
+               bottom = TAILQ_NEXT(bottom, entries);
 
        /* print rows lines and move bottom forward to the new screen bottom */
        for (; rows > 1; rows--) {
                scrollend = TAILQ_PREV(scrollend, tailhead, entries);
-               bottom = TAILQ_NEXT(bottom, entries);
+               if ( x + n >= ws.ws_row)
+                       bottom = TAILQ_NEXT(bottom, entries);
                write(STDOUT_FILENO, scrollend->buf, scrollend->size);
        }
        /* move cursor from line n to the old bottom position */
-       dprintf(STDOUT_FILENO, "\033[%d;0H", x);
+       if (x + n < ws.ws_row) {
+               dprintf(STDOUT_FILENO, "\033[%d;%dH", x + n, y);
+               write(STDOUT_FILENO, "\033[?25h", 6);   /* show cursor */
+       } else
+               dprintf(STDOUT_FILENO, "\033[%d;0H", ws.ws_row);
 }
 
 void