source: trunk/src/comctl32/smoothscroll.c@ 7948

/*
 * Undocumented SmoothScrollWindow function from COMCTL32.DLL
 *
 * Copyright 2000 Marcus Meissner <marcus@jet.franken.de>
 *
 * TODO
 *     - actually add smooth scrolling
 */

#include "winbase.h"
#include "winreg.h"
#include "winerror.h"
#include "commctrl.h"
#include "debugtools.h"

DEFAULT_DEBUG_CHANNEL(commctrl);

static DWORD    smoothscroll = 2;

#ifdef __WIN32OS2__
typedef BOOL (* CALLBACK SCROLLWINDOWEXPROC)(HWND,INT,INT,LPRECT,LPRECT,HRGN,LPRECT,DWORD);
#else
typedef BOOL (CALLBACK *SCROLLWINDOWEXPROC)(HWND,INT,INT,LPRECT,LPRECT,HRGN,LPRECT,DWORD);
#endif

typedef struct tagSMOOTHSCROLLSTRUCT {
        DWORD                   dwSize;
        DWORD                   x2;
        HWND                    hwnd;
        DWORD                   dx;

        DWORD                   dy;
        LPRECT                  lpscrollrect;
        LPRECT                  lpcliprect;
        HRGN                    hrgnupdate;

        LPRECT                  lpupdaterect;
        DWORD                   flags;
        DWORD                   stepinterval;
        DWORD                   dx_step;

        DWORD                   dy_step;
        SCROLLWINDOWEXPROC      scrollfun;      /* same parameters as ScrollWindowEx */
} SMOOTHSCROLLSTRUCT;

/**************************************************************************
 * SmoothScrollWindow [COMCTL32.382]
 *
 * Lots of magic for smooth scrolling windows.
 *
 * Currently only scrolls ONCE. The comctl32 implementation uses GetTickCount
 * and what else to do smooth scrolling.
 */

BOOL WINAPI SmoothScrollWindow( SMOOTHSCROLLSTRUCT *smooth ) {
   LPRECT       lpupdaterect = smooth->lpupdaterect;
   HRGN         hrgnupdate = smooth->hrgnupdate;
   RECT         tmprect;
   BOOL         ret = TRUE;
   DWORD        flags = smooth->flags;

   if (smooth->dwSize!=sizeof(SMOOTHSCROLLSTRUCT))
       return FALSE;

   if (!lpupdaterect)
       lpupdaterect = &tmprect;
   SetRectEmpty(lpupdaterect);

   if (!(flags & 0x40000)) { /* no override, use system wide defaults */
       if (smoothscroll == 2) {
           HKEY hkey;

           smoothscroll = 0;
           if (!RegOpenKeyA(HKEY_CURRENT_USER,"Control Panel\\Desktop",&hkey)) {
               DWORD    len = 4;

               RegQueryValueExA(hkey,"SmoothScroll",0,0,(LPBYTE)&smoothscroll,&len);
               RegCloseKey(hkey);
           }
       }
       if (!smoothscroll)
           flags |= 0x20000;
   }

   if (flags & 0x20000) { /* are we doing jump scrolling? */
       if ((smooth->x2 & 1) && smooth->scrollfun)
           return smooth->scrollfun(
               smooth->hwnd,smooth->dx,smooth->dy,smooth->lpscrollrect,
               smooth->lpcliprect,hrgnupdate,lpupdaterect,
               flags & 0xffff
           );
       else
           return ScrollWindowEx(
               smooth->hwnd,smooth->dx,smooth->dy,smooth->lpscrollrect,
               smooth->lpcliprect,hrgnupdate,lpupdaterect,
               flags & 0xffff
           );
   }

   FIXME("(hwnd=%x,flags=%lx,x2=%lx): should smooth scroll here.\n",
           smooth->hwnd,flags,smooth->x2
   );
   /* FIXME: do timer based smooth scrolling */
   if ((smooth->x2 & 1) && smooth->scrollfun)
       return smooth->scrollfun(
           smooth->hwnd,smooth->dx,smooth->dy,smooth->lpscrollrect,
           smooth->lpcliprect,hrgnupdate,lpupdaterect,
           flags & 0xffff
       );
   else
       return ScrollWindowEx(
           smooth->hwnd,smooth->dx,smooth->dy,smooth->lpscrollrect,
           smooth->lpcliprect,hrgnupdate,lpupdaterect,
           flags & 0xffff
       );
   return ret;
}