dlls/comctl32/smoothscroll.c

   1 /*
   2  * Undocumented SmoothScrollWindow function from COMCTL32.DLL
   3  *
   4  * Copyright 2000 Marcus Meissner <marcus@jet.franken.de>
   5  *
   6  * TODO
   7  *     - actually add smooth scrolling
   8  */
   9
  10 #include "winbase.h"
  11 #include "winreg.h"
  12 #include "winerror.h"
  13 #include "commctrl.h"
  14 #include "debugtools.h"
  15
  16 DEFAULT_DEBUG_CHANNEL(commctrl);
  17
  18 static DWORD    smoothscroll = 2;
  19
  20 typedef BOOL (CALLBACK *SCROLLWINDOWEXPROC)(HWND,INT,INT,LPRECT,LPRECT,HRGN,LPRECT,DWORD);
  21 typedef struct tagSMOOTHSCROLLSTRUCT {
  22         DWORD                   dwSize;
  23         DWORD                   x2;
  24         HWND                    hwnd;
  25         DWORD                   dx;
  26
  27         DWORD                   dy;
  28         LPRECT                  lpscrollrect;
  29         LPRECT                  lpcliprect;
  30         HRGN                    hrgnupdate;
  31
  32         LPRECT                  lpupdaterect;
  33         DWORD                   flags;
  34         DWORD                   stepinterval;
  35         DWORD                   dx_step;
  36
  37         DWORD                   dy_step;
  38         SCROLLWINDOWEXPROC      scrollfun;      /* same parameters as ScrollWindowEx */
  39 } SMOOTHSCROLLSTRUCT;
  40
  41 /**************************************************************************
  42  * SmoothScrollWindow [COMCTL32.382]
  43  *
  44  * Lots of magic for smooth scrolling windows.
  45  *
  46  * Currently only scrolls ONCE. The comctl32 implementation uses GetTickCount
  47  * and what else to do smooth scrolling.
  48  */
  49
  50 BOOL WINAPI SmoothScrollWindow( SMOOTHSCROLLSTRUCT *smooth ) {
  51    LPRECT       lpupdaterect = smooth->lpupdaterect;
  52    HRGN         hrgnupdate = smooth->hrgnupdate;
  53    RECT         tmprect;
  54    BOOL         ret = TRUE;
  55    DWORD        flags = smooth->flags;
  56
  57    if (smooth->dwSize!=sizeof(SMOOTHSCROLLSTRUCT))
  58        return FALSE;
  59
  60    if (!lpupdaterect)
  61        lpupdaterect = &tmprect;
  62    SetRectEmpty(lpupdaterect);
  63
  64    if (!(flags & 0x40000)) { /* no override, use system wide defaults */
  65        if (smoothscroll == 2) {
  66            HKEY hkey;
  67
  68            smoothscroll = 0;
  69            if (!RegOpenKeyA(HKEY_CURRENT_USER,"Control Panel\\Desktop",&hkey)) {
  70                DWORD    len = 4;
  71
  72                RegQueryValueExA(hkey,"SmoothScroll",0,0,(LPBYTE)&smoothscroll,&len);
  73                RegCloseKey(hkey);
  74            }
  75        }
  76        if (!smoothscroll)
  77            flags |= 0x20000;
  78    }
  79
  80    if (flags & 0x20000) { /* are we doing jump scrolling? */
  81        if ((smooth->x2 & 1) && smooth->scrollfun)
  82            return smooth->scrollfun(
  83                smooth->hwnd,smooth->dx,smooth->dy,smooth->lpscrollrect,
  84                smooth->lpcliprect,hrgnupdate,lpupdaterect,
  85                flags & 0xffff
  86            );
  87        else
  88            return ScrollWindowEx(
  89                smooth->hwnd,smooth->dx,smooth->dy,smooth->lpscrollrect,
  90                smooth->lpcliprect,hrgnupdate,lpupdaterect,
  91                flags & 0xffff
  92            );
  93    }
  94
  95    FIXME("(hwnd=%x,flags=%lx,x2=%lx): should smooth scroll here.\n",
  96            smooth->hwnd,flags,smooth->x2
  97    );
  98    /* FIXME: do timer based smooth scrolling */
  99    if ((smooth->x2 & 1) && smooth->scrollfun)
 100        return smooth->scrollfun(
 101            smooth->hwnd,smooth->dx,smooth->dy,smooth->lpscrollrect,
 102            smooth->lpcliprect,hrgnupdate,lpupdaterect,
 103            flags & 0xffff
 104        );
 105    else
 106        return ScrollWindowEx(
 107            smooth->hwnd,smooth->dx,smooth->dy,smooth->lpscrollrect,
 108            smooth->lpcliprect,hrgnupdate,lpupdaterect,
 109            flags & 0xffff
 110        );
 111    return ret;
 112 }