list_window: export scroll-after-cursor code

This moves the list_window_check_origin code into a new, more generic
function, which is exported.

diff --git a/src/list_window.c b/src/list_window.c
index 8e0b968149e88450d8b5e53370d6a682d7ee8029..ecd786b91d1f3b38b0f56e50e788c98a2feefb83 100644 (file)
--- a/src/list_window.c
+++ b/src/list_window.c
@@ -93,26 +93,7 @@ list_window_check_selected(struct list_window *lw)
 static void
 list_window_check_origin(struct list_window *lw)
 {
-       int start = lw->start;
-
-       if ((unsigned) options.scroll_offset * 2 >= lw->rows)
-               // Center if the offset is more than half the screen
-               start = lw->selected - lw->rows / 2;
-       else {
-               if (lw->selected < lw->start + options.scroll_offset)
-                       start = lw->selected - options.scroll_offset;
-
-               if (lw->selected >= lw->start + lw->rows - options.scroll_offset)
-                       start = lw->selected - lw->rows + 1 + options.scroll_offset;
-       }
-
-       if (start + lw->rows > lw->length)
-               start = lw->length - lw->rows;
-
-       if (start < 0 || lw->length == 0)
-               start = 0;
-
-       lw->start = start;
+       list_window_scroll_to(lw, lw->selected);
 }
 
 void
@@ -152,6 +133,31 @@ list_window_center(struct list_window *lw, unsigned n)
        }
 }
 
+void
+list_window_scroll_to(struct list_window *lw, unsigned n)
+{
+       int start = lw->start;
+
+       if ((unsigned) options.scroll_offset * 2 >= lw->rows)
+               // Center if the offset is more than half the screen
+               start = n - lw->rows / 2;
+       else {
+               if (n < lw->start + options.scroll_offset)
+                       start = n - options.scroll_offset;
+
+               if (n >= lw->start + lw->rows - options.scroll_offset)
+                       start = n - lw->rows + 1 + options.scroll_offset;
+       }
+
+       if (start + lw->rows > lw->length)
+               start = lw->length - lw->rows;
+
+       if (start < 0 || lw->length == 0)
+               start = 0;
+
+       lw->start = start;
+}
+
 void
 list_window_set_cursor(struct list_window *lw, unsigned i)
 {

diff --git a/src/list_window.h b/src/list_window.h
index 83beeacaa47f492c162abf4998a2ab7b42349929..8f67c858523602f59f99b4c886853913fb3849a1 100644 (file)
--- a/src/list_window.h
+++ b/src/list_window.h
@@ -127,6 +127,13 @@ list_window_mouse(struct list_window *lw, unsigned long bstate, int y);
 void
 list_window_center(struct list_window *lw, unsigned n);
 
+/**
+ * Scrolls the view to item n, as if the cursor would have been moved
+ * to the position.
+ */
+void
+list_window_scroll_to(struct list_window *lw, unsigned n);
+
 /**
  * Sets the position of the cursor.  Disables range selection.
  */