--- rxvt-unicode/src/scrollbar.h	2008/02/19 13:01:33	1.20
+++ rxvt-unicode/src/scrollbar.h	2011/08/28 18:48:41	1.27
@@ -2,18 +2,10 @@
 #define SCROLLBAR_H
 
 #include <X11/Xlib.h>
+#include "rxvtutil.h"
 
 struct rxvt_term;
 
-#define R_SB_NEXT               1
-#define R_SB_XTERM              2
-#define R_SB_PLAIN              4
-#define R_SB_RXVT               8
-
-#define R_SB_ALIGN_CENTRE       0
-#define R_SB_ALIGN_TOP          1
-#define R_SB_ALIGN_BOTTOM       2
-
 #define SB_WIDTH_NEXT           19
 #define SB_WIDTH_XTERM          15
 #define SB_WIDTH_PLAIN          7
@@ -40,36 +32,48 @@
 #define SB_THUMB_MIN_HEIGHT     (SB_BUTTON_WIDTH - (SB_PADDING * 2))
 
 enum sb_state {
-  STATE_IDLE = 1,
+  STATE_OFF,
+  STATE_IDLE,
   STATE_MOTION,
   STATE_UP,
   STATE_DOWN,
 };
 
-struct scrollBar_t {
+enum sb_style {
+  R_SB_NEXT  = 1,
+  R_SB_XTERM = 2,
+  R_SB_PLAIN = 4,
+  R_SB_RXVT  = 8,
+};
+
+enum sb_align {
+  R_SB_ALIGN_CENTRE,
+  R_SB_ALIGN_TOP,
+  R_SB_ALIGN_BOTTOM,
+};
+
+struct scrollBar_t
+{
   rxvt_term *term;
-  char            state;        /* scrollbar state                          */
+  sb_state        state;        /* scrollbar state                          */
   char            init;         /* scrollbar has been initialised           */
-  unsigned int    beg;          /* slider sub-window begin height           */
-  unsigned int    end;          /* slider sub-window end height             */
-  unsigned int    top;          /* slider top position                      */
-  unsigned int    bot;          /* slider bottom position                   */
-  unsigned int    style;        /* style: rxvt, xterm, next                 */
-  unsigned int    width;        /* scrollbar width                          */
+  int             beg;          /* slider sub-window begin height           */
+  int             end;          /* slider sub-window end height             */
+  int             top;          /* slider top position                      */
+  int             bot;          /* slider bottom position                   */
+  sb_style        style;        /* style: rxvt, xterm, next                 */
+  int             width;        /* scrollbar width                          */
   int             shadow;       /* scrollbar shadow width                   */
   int             last_bot;     /* scrollbar last bottom position           */
   int             last_top;     /* scrollbar last top position              */
   int             last_state;   /* scrollbar last state                     */
-  int             len;
-  unsigned char   align;
+  sb_align        align;
   Window          win;
   Cursor          leftptr_cursor;
   int             (scrollBar_t::*update)(int);
   void setup (rxvt_term *);
-  // update style dependent data
-  void update_data ();
   void resize ();
-  int map (int);
+  void map (int);
   int show (int);
   void destroy ();
 
@@ -89,18 +93,31 @@
       return y > end;
     return false;
   }
-  unsigned min_height ()
+  int min_height ()
   {
     return style == R_SB_NEXT ? SB_THUMB_MIN_HEIGHT : 10;
   }
-  unsigned size ()
+  int size ()
   {
-    return end - beg - min_height ();
+    return max (end - beg - min_height (), 0);
   }
-  unsigned total_width ()
+  int total_width ()
   {
     return width + shadow * 2;
   }
+  bool above_slider (int y)
+  {
+    return y < top;
+  }
+  bool below_slider (int y)
+  {
+    return y > bot;
+  }
+  int position (int y)
+  {
+    return y - beg;
+  }
+
 
 #if defined(NEXT_SCROLLBAR)
   GC              blackGC,
@@ -130,6 +147,10 @@
   GC              pscrollbarGC;
 #endif
 
+private:
+  // update style dependent data
+  void update_data ();
+
   // scrollbar-next.C
   int show_next (int);
   // scrollbar-rxvt.C
@@ -139,14 +160,9 @@
   // scrollbar-plain.C
   int show_plain (int);
 
-private:
   void init_next ();
 };
 
-#define scrollbar_above_slider(y)       ((y) < scrollBar.top)
-#define scrollbar_below_slider(y)       ((y) > scrollBar.bot)
-#define scrollbar_position(y)           ((y) - scrollBar.beg)
-
  /*
   *    +-------------+
   *    |             | <---< SB_PADDING