xref: /reactos/dll/win32/comctl32/smoothscroll.c (revision c2c66aff)
1 /*
2  * Undocumented SmoothScrollWindow function from COMCTL32.DLL
3  *
4  * Copyright 2000 Marcus Meissner <marcus@jet.franken.de>
5  *
6  * This library is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * This library is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with this library; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
19  *
20  * TODO
21  *     - actually add smooth scrolling
22  */
23 
24 #include "comctl32.h"
25 
26 WINE_DEFAULT_DEBUG_CHANNEL(commctrl);
27 
28 static DWORD	smoothscroll = 2;
29 
30 typedef BOOL (CALLBACK *SCROLLWINDOWEXPROC)(HWND,INT,INT,LPRECT,LPRECT,HRGN,LPRECT,DWORD);
31 typedef struct tagSMOOTHSCROLLSTRUCT {
32 	DWORD			dwSize;
33 	DWORD			x2;
34 	HWND			hwnd;
35 	DWORD			dx;
36 
37 	DWORD			dy;
38 	LPRECT			lpscrollrect;
39 	LPRECT			lpcliprect;
40 	HRGN			hrgnupdate;
41 
42 	LPRECT			lpupdaterect;
43 	DWORD			flags;
44 	DWORD			stepinterval;
45 	DWORD			dx_step;
46 
47 	DWORD			dy_step;
48 	SCROLLWINDOWEXPROC	scrollfun;	/* same parameters as ScrollWindowEx */
49 } SMOOTHSCROLLSTRUCT;
50 
51 /**************************************************************************
52  * SmoothScrollWindow [COMCTL32.382]
53  *
54  * Lots of magic for smooth scrolling windows.
55  *
56  * RETURNS
57  *     Success: TRUE
58  *     Failure: FALSE
59  *
60  * BUGS
61  *     Currently only scrolls ONCE. The comctl32 implementation uses GetTickCount
62  *     and what else to do smooth scrolling.
63  */
64 BOOL WINAPI SmoothScrollWindow( const SMOOTHSCROLLSTRUCT *smooth ) {
65    LPRECT	lpupdaterect = smooth->lpupdaterect;
66    HRGN		hrgnupdate = smooth->hrgnupdate;
67    RECT		tmprect;
68    DWORD	flags = smooth->flags;
69 
70    if (smooth->dwSize!=sizeof(SMOOTHSCROLLSTRUCT))
71        return FALSE;
72 
73    if (!lpupdaterect)
74        lpupdaterect = &tmprect;
75    SetRectEmpty(lpupdaterect);
76 
77    if (!(flags & 0x40000)) { /* no override, use system wide defaults */
78        if (smoothscroll == 2) {
79 	   HKEY	hkey;
80 
81 	   smoothscroll = 0;
82 	   if (!RegOpenKeyA(HKEY_CURRENT_USER,"Control Panel\\Desktop",&hkey)) {
83 	       DWORD	len = 4;
84 
85 	       RegQueryValueExA(hkey,"SmoothScroll",0,0,(LPBYTE)&smoothscroll,&len);
86 	       RegCloseKey(hkey);
87 	   }
88        }
89        if (!smoothscroll)
90 	   flags |= 0x20000;
91    }
92 
93    if (flags & 0x20000) { /* are we doing jump scrolling? */
94        if ((smooth->x2 & 1) && smooth->scrollfun)
95 	   return smooth->scrollfun(
96 	       smooth->hwnd,smooth->dx,smooth->dy,smooth->lpscrollrect,
97 	       smooth->lpcliprect,hrgnupdate,lpupdaterect,
98 	       flags & 0xffff
99 	   );
100        else
101 	   return ScrollWindowEx(
102 	       smooth->hwnd,smooth->dx,smooth->dy,smooth->lpscrollrect,
103 	       smooth->lpcliprect,hrgnupdate,lpupdaterect,
104 	       flags & 0xffff
105 	   );
106    }
107 
108    FIXME("(hwnd=%p,flags=%x,x2=%x): should smooth scroll here.\n",
109 	   smooth->hwnd,flags,smooth->x2
110    );
111    /* FIXME: do timer based smooth scrolling */
112    if ((smooth->x2 & 1) && smooth->scrollfun)
113        return smooth->scrollfun(
114 	   smooth->hwnd,smooth->dx,smooth->dy,smooth->lpscrollrect,
115 	   smooth->lpcliprect,hrgnupdate,lpupdaterect,
116 	   flags & 0xffff
117        );
118    else
119        return ScrollWindowEx(
120 	   smooth->hwnd,smooth->dx,smooth->dy,smooth->lpscrollrect,
121 	   smooth->lpcliprect,hrgnupdate,lpupdaterect,
122 	   flags & 0xffff
123        );
124 }
125