From 27865304d7da65e4638af07c4307aba5a7fd18eb Mon Sep 17 00:00:00 2001
From: David Lawrence Ramsey <pooka109@gmail.com>
Date: Sat, 23 Jul 2005 20:39:41 +0000
Subject: [PATCH] remove more redundant screen updates in edit_scroll(), and
 add a few more miscellaneous cleanups

git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@2914 35c25a1d-7b9e-4130-9fde-d3aeb78583b8
---
 ChangeLog   |  2 +-
 src/winio.c | 26 ++++++++++++++++++--------
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 0413b364..31b52306 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -193,7 +193,7 @@ CVS code -
 	- Clean up and simplify. (DLR)
   edit_update()
 	- Since we no longer use TOP, remove references to it.  Also,
-	  don't call edit_refresh() anymore: it will call us. (DLR)
+	  don't call edit_refresh() anymore; it will call us. (DLR)
   do_statusbar_next_word()
 	- Rework to be more like do_statusbar_prev_word(), to avoid a
 	  potential problem if we start at the end of a line. (DLR)
diff --git a/src/winio.c b/src/winio.c
index 5ffbb2c6..8ae8964e 100644
--- a/src/winio.c
+++ b/src/winio.c
@@ -3493,6 +3493,7 @@ int need_vertical_update(size_t old_pww)
  * assume that current and current_x are up to date. */
 void edit_scroll(updown direction, int nlines)
 {
+    bool do_redraw = need_vertical_update(0);
     const filestruct *foo;
     int i;
 
@@ -3533,7 +3534,7 @@ void edit_scroll(updown direction, int nlines)
 
     /* If we scrolled up, we couldn't scroll up all nlines lines, and
      * we're now at the top of the file, we need to draw the entire edit
-     * window instead of just its top nlines lines. */
+     * window. */
     if (direction == UP && i > 0 && openfile->edittop ==
 	openfile->fileage)
 	nlines = editwinrows - 2;
@@ -3555,10 +3556,19 @@ void edit_scroll(updown direction, int nlines)
 	    foo = foo->next;
     }
 
-    /* Draw new lines on the blank lines before, inside, and after the
-     * scrolled region. */
-    for (; nlines > 0 && foo != NULL; nlines--) {
-	update_line(foo, (foo == openfile->current) ?
+    /* Draw new lines on any blank lines before or inside the scrolled
+     * region.  If we scrolled down and we're on the top line, or if we
+     * scrolled up and we're on the bottom line, the line won't be
+     * blank, so we don't need to draw it unless the mark is on or we're
+     * not on the first page. */
+    for (i = nlines; i > 0 && foo != NULL; i--) {
+	if ((i == nlines && direction == DOWN) || (i == 1 &&
+		direction == UP)) {
+	    if (do_redraw)
+		update_line(foo, (foo == openfile->current) ?
+			openfile->current_x : 0);
+	} else
+	    update_line(foo, (foo == openfile->current) ?
 		openfile->current_x : 0);
 	foo = foo->next;
     }
@@ -3568,7 +3578,7 @@ void edit_scroll(updown direction, int nlines)
  * updated. */
 void edit_redraw(const filestruct *old_current, size_t old_pww)
 {
-    bool do_refresh = need_vertical_update(0) ||
+    bool do_redraw = need_vertical_update(0) ||
 	need_vertical_update(old_pww);
     const filestruct *foo;
 
@@ -3589,7 +3599,7 @@ void edit_redraw(const filestruct *old_current, size_t old_pww)
     foo = old_current;
 
     while (foo != openfile->current) {
-	if (do_refresh)
+	if (do_redraw)
 	    update_line(foo, 0);
 
 #ifndef NANO_SMALL
@@ -3603,7 +3613,7 @@ void edit_redraw(const filestruct *old_current, size_t old_pww)
 #endif
     }
 
-    if (do_refresh)
+    if (do_redraw)
 	update_line(openfile->current, openfile->current_x);
 }
 
-- 
2.39.5