tweaks: rename a function, and adjust some comments

src/move.c

@@ -385,7 +385,7 @@ void do_home(void)
 
     openfile->placewewant = xplustabs();
 
-    if (need_screen_update(was_column, openfile->placewewant))
+    if (need_horizontal_scroll(was_column, openfile->placewewant))
 	update_line(openfile->current, openfile->current_x);
 }
 
@@ -397,7 +397,7 @@ void do_end(void)
     openfile->current_x = strlen(openfile->current->data);
     openfile->placewewant = xplustabs();
 
-    if (need_screen_update(was_column, openfile->placewewant))
+    if (need_horizontal_scroll(was_column, openfile->placewewant))
 	update_line(openfile->current, openfile->current_x);
 }
 
@@ -439,12 +439,11 @@ void do_up(bool scroll_only)
 #endif
 		editwinrows / 2 + 1);
 
-    /* If we're not on the first line of the edit window, and the target
-     * column is beyond the screen or the mark is on, redraw the prior
-     * and current lines. */
-    if (need_screen_update(was_column, 0))
+    /* Redraw the prior line if it was horizontally scrolled. */
+    if (need_horizontal_scroll(was_column, 0))
 	update_line(openfile->current->next, 0);
-    if (need_screen_update(0, xplustabs()))
+    /* Redraw the current line if it needs to be horizontally scrolled. */
+    if (need_horizontal_scroll(0, xplustabs()))
 	update_line(openfile->current, openfile->current_x);
 }
 
@@ -522,12 +521,11 @@ void do_down(bool scroll_only)
 	}
     }
 
-    /* If we're not on the last line of the edit window, and the target
-     * column is beyond the screen or the mark is on, redraw the prior
-     * and current lines. */
-    if (need_screen_update(was_column, 0))
+    /* Redraw the prior line if it was horizontally scrolled. */
+    if (need_horizontal_scroll(was_column, 0))
 	update_line(openfile->current->prev, 0);
-    if (need_screen_update(0, xplustabs()))
+    /* Redraw the current line if it needs to be horizontally scrolled. */
+    if (need_horizontal_scroll(0, xplustabs()))
 	update_line(openfile->current, openfile->current_x);
 }
 
@@ -566,7 +564,7 @@ void do_left(void)
 
     openfile->placewewant = xplustabs();
 
-    if (need_screen_update(was_column, openfile->placewewant))
+    if (need_horizontal_scroll(was_column, openfile->placewewant))
 	update_line(openfile->current, openfile->current_x);
 }
 
@@ -583,7 +581,7 @@ void do_right(void)
     else if (openfile->current != openfile->filebot) {
 	openfile->current_x = 0;
 	openfile->placewewant = 0;
-	if (need_screen_update(was_column, 0))
+	if (need_horizontal_scroll(was_column, 0))
 	    update_line(openfile->current, 0);
 	do_down_void();
 	return;
@@ -591,6 +589,6 @@ void do_right(void)
 
     openfile->placewewant = xplustabs();
 
-    if (need_screen_update(was_column, openfile->placewewant))
+    if (need_horizontal_scroll(was_column, openfile->placewewant))
 	update_line(openfile->current, openfile->current_x);
 }

src/proto.h

@@ -785,7 +785,7 @@ void reset_cursor(void);
 void edit_draw(filestruct *fileptr, const char *converted, int
 	line, size_t start);
 int update_line(filestruct *fileptr, size_t index);
-bool need_screen_update(const size_t old_column, const size_t new_column);
+bool need_horizontal_scroll(const size_t old_column, const size_t new_column);
 void edit_scroll(scroll_dir direction, ssize_t nlines);
 void edit_redraw(filestruct *old_current);
 void edit_refresh(void);

src/winio.c

@@ -2602,16 +2602,16 @@ int update_line(filestruct *fileptr, size_t index)
     return extralinesused;
 }
 
-/* Return TRUE if we need an update after moving the cursor, and
- * FALSE otherwise.  We need an update if the mark is on, or if
- * old_column and new_column are on different pages. */
-bool need_screen_update(const size_t old_column, const size_t new_column)
+/* Check whether old_column and new_column are on different "pages" (or that
+ * the mark is on), which means that the relevant line needs to be redrawn. */
+bool need_horizontal_scroll(const size_t old_column, const size_t new_column)
 {
-    return
 #ifndef NANO_TINY
-	openfile->mark_set ||
+    if (openfile->mark_set)
+	return TRUE;
+    else
 #endif
-	get_page_start(old_column) != get_page_start(new_column);
+	return (get_page_start(old_column) != get_page_start(new_column));
 }
 
 /* When edittop changes, try and figure out how many lines
@@ -2740,7 +2740,7 @@ void edit_scroll(scroll_dir direction, ssize_t nlines)
     for (i = nlines; i > 0 && foo != NULL; i--) {
 	if ((i == nlines && direction == DOWNWARD) || (i == 1 &&
 		direction == UPWARD)) {
-	    if (need_screen_update(openfile->placewewant, 0))
+	    if (need_horizontal_scroll(openfile->placewewant, 0))
 		update_line(foo, (foo == openfile->current) ?
 			openfile->current_x : 0);
 	} else
@@ -2786,7 +2786,7 @@ void edit_redraw(filestruct *old_current)
 
     /* Update current if we've changed page, or if it differs from
      * old_current and needs to be horizontally scrolled. */
-    if (need_screen_update(was_pww, openfile->placewewant) ||
+    if (need_horizontal_scroll(was_pww, openfile->placewewant) ||
 			(old_current != openfile->current &&
 			get_page_start(openfile->placewewant) > 0))
 	update_line(openfile->current, openfile->current_x);