From ad4e0425a6860803e5f31a08c349cd99e02e2847 Mon Sep 17 00:00:00 2001
From: Jari Vetoniemi <mailroxas@gmail.com>
Date: Sat, 12 Apr 2014 18:42:30 +0300
Subject: [PATCH] Make page scrolling work like it should. (Shfit+pgup/pgdwn
 for old behaviour)

---
 lib/bemenu.h      |  2 ++
 lib/draw/curses.c | 13 +++++++++++++
 lib/internal.h    |  5 +++++
 lib/menu.c        | 17 ++++++++++++++++-
 4 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/lib/bemenu.h b/lib/bemenu.h
index d348ffa..0b0769d 100644
--- a/lib/bemenu.h
+++ b/lib/bemenu.h
@@ -77,6 +77,8 @@ typedef enum bmKey {
     BM_KEY_END,
     BM_KEY_PAGE_UP,
     BM_KEY_PAGE_DOWN,
+    BM_KEY_SHIFT_PAGE_UP,
+    BM_KEY_SHIFT_PAGE_DOWN,
     BM_KEY_BACKSPACE,
     BM_KEY_DELETE,
     BM_KEY_LINE_DELETE_LEFT,
diff --git a/lib/draw/curses.c b/lib/draw/curses.c
index 653a07d..b54693f 100644
--- a/lib/draw/curses.c
+++ b/lib/draw/curses.c
@@ -198,6 +198,12 @@ static void _bmDrawCursesRender(const bmMenu *menu)
     curses.refresh();
 }
 
+static unsigned int _bmDrawCursesDisplayedCount(const bmMenu *menu)
+{
+    (void)menu;
+    return (curses.stdscr ? curses.getmaxy(curses.stdscr) : 0);
+}
+
 static void _bmDrawCursesEndWin(void)
 {
     freopen(TTY, "w", stdout);
@@ -258,6 +264,12 @@ static bmKey _bmDrawCursesGetKey(unsigned int *unicode)
         case KEY_NPAGE: /* Page down */
             return BM_KEY_PAGE_DOWN;
 
+        case 398: /* S-Page up */
+            return BM_KEY_SHIFT_PAGE_UP;
+
+        case 396: /* S-Page down */
+            return BM_KEY_SHIFT_PAGE_DOWN;
+
         case 8: /* C-h */
         case 127: /* Delete */
         case KEY_BACKSPACE:
@@ -361,6 +373,7 @@ int _bmDrawCursesInit(struct _bmRenderApi *api)
 
 #undef bmLoadFunction
 
+    api->displayedCount = _bmDrawCursesDisplayedCount;
     api->getKey = _bmDrawCursesGetKey;
     api->render = _bmDrawCursesRender;
     api->free = _bmDrawCursesFree;
diff --git a/lib/internal.h b/lib/internal.h
index 2acd6f5..b3ca87c 100644
--- a/lib/internal.h
+++ b/lib/internal.h
@@ -27,6 +27,11 @@ struct _bmItem {
  * Renderers should be able to fill this one as they see fit.
  */
 struct _bmRenderApi {
+    /**
+     * Get count of displayed items by the underlying renderer.
+     */
+    unsigned int (*displayedCount)(const bmMenu *menu);
+
     /**
      * If the underlying renderer is a UI toolkit. (curses, etc...)
      * There might be possibility to get user input, and this should be thus implemented.
diff --git a/lib/menu.c b/lib/menu.c
index 0457da8..e819dd5 100644
--- a/lib/menu.c
+++ b/lib/menu.c
@@ -532,6 +532,13 @@ bmRunResult bmMenuRunWithKey(bmMenu *menu, bmKey key, unsigned int unicode)
     unsigned int itemsCount;
     bmMenuGetFilteredItems(menu, &itemsCount);
 
+    unsigned int displayed = 0;
+    if (menu->renderApi.displayedCount)
+        displayed = menu->renderApi.displayedCount(menu);
+
+    if (!displayed)
+        displayed = itemsCount;
+
     switch (key) {
         case BM_KEY_LEFT:
             {
@@ -569,10 +576,18 @@ bmRunResult bmMenuRunWithKey(bmMenu *menu, bmKey key, unsigned int unicode)
             break;
 
         case BM_KEY_PAGE_UP:
-            menu->index = 0;
+            menu->index = (menu->index < displayed ? 0 : menu->index - (displayed - 1));
             break;
 
         case BM_KEY_PAGE_DOWN:
+            menu->index = (menu->index + displayed >= itemsCount ? itemsCount - 1 : menu->index + (displayed - 1));
+            break;
+
+        case BM_KEY_SHIFT_PAGE_UP:
+            menu->index = 0;
+            break;
+
+        case BM_KEY_SHIFT_PAGE_DOWN:
             menu->index = itemsCount - 1;
             break;