git.oblomov.eu Git - wine/blob - windows/painting.c

   1 /*
   2  * Window painting functions
   3  *
   4  * Copyright 1993, 1994, 1995 Alexandre Julliard
   5  *                       1999 Alex Korobka
   6  */
   7
   8 #include "region.h"
   9 #include "win.h"
  10 #include "queue.h"
  11 #include "dce.h"
  12 #include "heap.h"
  13 #include "debugtools.h"
  14 #include "wine/winuser16.h"
  15
  16 DECLARE_DEBUG_CHANNEL(nonclient)
  17 DECLARE_DEBUG_CHANNEL(win)
  18
  19 /* client rect in window coordinates */
  20
  21 #define GETCLIENTRECTW( wnd, r )        (r).left = (wnd)->rectClient.left - (wnd)->rectWindow.left; \
  22                                         (r).top = (wnd)->rectClient.top - (wnd)->rectWindow.top; \
  23                                         (r).right = (wnd)->rectClient.right - (wnd)->rectWindow.left; \
  24                                         (r).bottom = (wnd)->rectClient.bottom - (wnd)->rectWindow.top
  25
  26   /* Last CTLCOLOR id */
  27 #define CTLCOLOR_MAX   CTLCOLOR_STATIC
  28
  29
  30 /***********************************************************************
  31  *           WIN_UpdateNCRgn
  32  *
  33  *  Things to do:
  34  *      Send WM_NCPAINT if required (when nonclient is invalid or UNC_ENTIRE flag is set)
  35  *      Crop hrgnUpdate to a client rect, especially if it 1.
  36  *      If UNC_REGION is set return update region for the client rect.
  37  *
  38  *  NOTE: UNC_REGION is mainly for the RDW_Paint() chunk that sends WM_ERASEBKGND message.
  39  *        The trick is that when the returned region handle may be different from hRgn.
  40  *        In this case the old hRgn must be considered gone. BUT, if the returned value
  41  *        is 1 then the hRgn is preserved and RDW_Paint() will have to get
  42  *        a DC without extra clipping region.
  43  */
  44 HRGN WIN_UpdateNCRgn(WND* wnd, HRGN hRgn, UINT uncFlags )
  45 {
  46     RECT  r;
  47     HRGN  hClip = 0;
  48     HRGN  hrgnRet = 0;
  49
  50     TRACE_(nonclient)("hwnd %04x [%04x] hrgn %04x, unc %04x, ncf %i\n",
  51                       wnd->hwndSelf, wnd->hrgnUpdate, hRgn, uncFlags, wnd->flags & WIN_NEEDS_NCPAINT);
  52
  53     /* desktop window doesn't have a nonclient area */
  54     if(wnd == WIN_GetDesktop())
  55     {
  56         wnd->flags &= ~WIN_NEEDS_NCPAINT;
  57         if( wnd->hrgnUpdate > 1 )
  58             hrgnRet = REGION_CropRgn( hRgn, wnd->hrgnUpdate, NULL, NULL );
  59         else
  60         {
  61             hrgnRet = wnd->hrgnUpdate;
  62         }
  63         WIN_ReleaseDesktop();
  64         return hrgnRet;
  65     }
  66     WIN_ReleaseDesktop();
  67
  68     if ((wnd->hwndSelf == GetForegroundWindow()) &&
  69         !(wnd->flags & WIN_NCACTIVATED) )
  70     {
  71         wnd->flags |= WIN_NCACTIVATED;
  72         uncFlags |= UNC_ENTIRE;
  73     }
  74
  75     if( wnd->flags & WIN_NEEDS_NCPAINT )
  76     {
  77             RECT r2, r3;
  78
  79             wnd->flags &= ~WIN_NEEDS_NCPAINT;
  80             GETCLIENTRECTW( wnd, r );
  81
  82             TRACE_(nonclient)( "\tclient box (%i,%i-%i,%i), hrgnUpdate %04x\n",
  83                                 r.left, r.top, r.right, r.bottom, wnd->hrgnUpdate );
  84             if( wnd->hrgnUpdate > 1 )
  85             {
  86                 /* Check if update rgn overlaps with nonclient area */
  87
  88                 GetRgnBox( wnd->hrgnUpdate, &r2 );
  89                 UnionRect( &r3, &r2, &r );
  90                 if( r3.left != r.left || r3.top != r.top ||
  91                     r3.right != r.right || r3.bottom != r.bottom ) /* it does */
  92                 {
  93                     /* crop hrgnUpdate, save old one in hClip - the only
  94                      * case that places a valid region handle in hClip */
  95
  96                     hClip = wnd->hrgnUpdate;
  97                     wnd->hrgnUpdate = REGION_CropRgn( hRgn, hClip, &r, NULL );
  98                     if( uncFlags & UNC_REGION ) hrgnRet = hClip;
  99                 }
 100
 101                 if( uncFlags & UNC_CHECK )
 102                 {
 103                     GetRgnBox( wnd->hrgnUpdate, &r3 );
 104                     if( IsRectEmpty( &r3 ) )
 105                     {
 106                         /* delete the update region since all invalid
 107                          * parts were in the nonclient area */
 108
 109                         DeleteObject( wnd->hrgnUpdate );
 110                         wnd->hrgnUpdate = 0;
 111                         if(!(wnd->flags & WIN_INTERNAL_PAINT))
 112                             QUEUE_DecPaintCount( wnd->hmemTaskQ );
 113
 114                         wnd->flags &= ~WIN_NEEDS_ERASEBKGND;
 115                     }
 116                 }
 117
 118                 if(!hClip && wnd->hrgnUpdate ) goto copyrgn;
 119             }
 120             else
 121             if( wnd->hrgnUpdate == 1 )/* entire window */
 122             {
 123                 if( uncFlags & UNC_UPDATE ) wnd->hrgnUpdate = CreateRectRgnIndirect( &r );
 124                 if( uncFlags & UNC_REGION ) hrgnRet = 1;
 125                 uncFlags |= UNC_ENTIRE;
 126             }
 127     }
 128     else /* no WM_NCPAINT unless forced */
 129     {
 130         if( wnd->hrgnUpdate >  1 )
 131         {
 132 copyrgn:
 133             if( uncFlags & UNC_REGION )
 134                 hrgnRet = REGION_CropRgn( hRgn, wnd->hrgnUpdate, NULL, NULL );
 135         }
 136         else
 137         if( wnd->hrgnUpdate == 1 && (uncFlags & UNC_UPDATE) )
 138         {
 139             GETCLIENTRECTW( wnd, r );
 140             wnd->hrgnUpdate = CreateRectRgnIndirect( &r );
 141             if( uncFlags & UNC_REGION ) hrgnRet = 1;
 142         }
 143     }
 144
 145     if(!hClip && (uncFlags & UNC_ENTIRE) )
 146     {
 147         /* still don't do anything if there is no nonclient area */
 148         hClip = (memcmp( &wnd->rectWindow, &wnd->rectClient, sizeof(RECT) ) != 0);
 149     }
 150
 151     if( hClip ) /* NOTE: WM_NCPAINT allows wParam to be 1 */
 152     {
 153         SendMessageA( wnd->hwndSelf, WM_NCPAINT, hClip, 0L );
 154         if( (hClip > 1)&& (hClip != hRgn) && (hClip != hrgnRet) ) DeleteObject( hClip );
 155         /*
 156          * Since all Window locks are suspended while processing the WM_NCPAINT
 157          * we want to make sure the window still exists before continuing.
 158          */
 159         if (!IsWindow(wnd->hwndSelf))
 160         {
 161           DeleteObject(hrgnRet);
 162           hrgnRet=0;
 163         }
 164     }
 165
 166     TRACE_(nonclient)("returning %04x (hClip = %04x, hrgnUpdate = %04x)\n", hrgnRet, hClip, wnd->hrgnUpdate );
 167
 168     return hrgnRet;
 169 }
 170
 171
 172 /***********************************************************************
 173  *           BeginPaint16    (USER.39)
 174  */
 175 HDC16 WINAPI BeginPaint16( HWND16 hwnd, LPPAINTSTRUCT16 lps )
 176 {
 177     BOOL bIcon;
 178     HRGN hrgnUpdate;
 179     WND *wndPtr = WIN_FindWndPtr( hwnd );
 180     if (!wndPtr) return 0;
 181
 182     bIcon = (wndPtr->dwStyle & WS_MINIMIZE && GetClassWord(wndPtr->hwndSelf, GCW_HICON));
 183
 184     wndPtr->flags &= ~WIN_NEEDS_BEGINPAINT;
 185
 186     /* send WM_NCPAINT and make sure hrgnUpdate is a valid rgn handle */
 187     WIN_UpdateNCRgn( wndPtr, 0, UNC_UPDATE );
 188
 189     /*
 190      * Make sure the window is still a window. All window locks are suspended
 191      * when the WM_NCPAINT is sent.
 192      */
 193     if (!IsWindow(wndPtr->hwndSelf))
 194     {
 195         WIN_ReleaseWndPtr(wndPtr);
 196         return 0;
 197     }
 198
 199     if( ((hrgnUpdate = wndPtr->hrgnUpdate) != 0) || (wndPtr->flags & WIN_INTERNAL_PAINT))
 200         QUEUE_DecPaintCount( wndPtr->hmemTaskQ );
 201
 202     wndPtr->hrgnUpdate = 0;
 203     wndPtr->flags &= ~WIN_INTERNAL_PAINT;
 204
 205     HideCaret( hwnd );
 206
 207     TRACE_(win)("hrgnUpdate = %04x, \n", hrgnUpdate);
 208
 209     if (GetClassWord16(wndPtr->hwndSelf, GCW_STYLE) & CS_PARENTDC)
 210     {
 211         /* Don't clip the output to the update region for CS_PARENTDC window */
 212         if( hrgnUpdate )
 213             DeleteObject(hrgnUpdate);
 214         lps->hdc = GetDCEx16( hwnd, 0, DCX_WINDOWPAINT | DCX_USESTYLE |
 215                               (bIcon ? DCX_WINDOW : 0) );
 216     }
 217     else
 218     {
 219         if( hrgnUpdate ) /* convert to client coordinates */
 220             OffsetRgn( hrgnUpdate, wndPtr->rectWindow.left - wndPtr->rectClient.left,
 221                                    wndPtr->rectWindow.top - wndPtr->rectClient.top );
 222         lps->hdc = GetDCEx16(hwnd, hrgnUpdate, DCX_INTERSECTRGN |
 223                              DCX_WINDOWPAINT | DCX_USESTYLE | (bIcon ? DCX_WINDOW : 0) );
 224         /* ReleaseDC() in EndPaint() will delete the region */
 225     }
 226
 227     TRACE_(win)("hdc = %04x\n", lps->hdc);
 228
 229     if (!lps->hdc)
 230     {
 231         WARN_(win)("GetDCEx() failed in BeginPaint(), hwnd=%04x\n", hwnd);
 232         WIN_ReleaseWndPtr(wndPtr);
 233         return 0;
 234     }
 235
 236     GetClipBox16( lps->hdc, &lps->rcPaint );
 237
 238     TRACE_(win)("box = (%i,%i - %i,%i)\n", lps->rcPaint.left, lps->rcPaint.top,
 239                     lps->rcPaint.right, lps->rcPaint.bottom );
 240
 241     if (wndPtr->flags & WIN_NEEDS_ERASEBKGND)
 242     {
 243         wndPtr->flags &= ~WIN_NEEDS_ERASEBKGND;
 244         lps->fErase = !SendMessage16(hwnd, (bIcon) ? WM_ICONERASEBKGND
 245                                                    : WM_ERASEBKGND,
 246                                      (WPARAM16)lps->hdc, 0 );
 247     }
 248     else lps->fErase = TRUE;
 249
 250     WIN_ReleaseWndPtr(wndPtr);
 251     return lps->hdc;
 252 }
 253
 254
 255 /***********************************************************************
 256  *           BeginPaint32    (USER32.10)
 257  */
 258 HDC WINAPI BeginPaint( HWND hwnd, PAINTSTRUCT *lps )
 259 {
 260     PAINTSTRUCT16 ps;
 261
 262     BeginPaint16( hwnd, &ps );
 263     lps->hdc            = (HDC)ps.hdc;
 264     lps->fErase         = ps.fErase;
 265     lps->rcPaint.top    = ps.rcPaint.top;
 266     lps->rcPaint.left   = ps.rcPaint.left;
 267     lps->rcPaint.right  = ps.rcPaint.right;
 268     lps->rcPaint.bottom = ps.rcPaint.bottom;
 269     lps->fRestore       = ps.fRestore;
 270     lps->fIncUpdate     = ps.fIncUpdate;
 271     return lps->hdc;
 272 }
 273
 274
 275 /***********************************************************************
 276  *           EndPaint16    (USER.40)
 277  */
 278 BOOL16 WINAPI EndPaint16( HWND16 hwnd, const PAINTSTRUCT16* lps )
 279 {
 280     ReleaseDC16( hwnd, lps->hdc );
 281     ShowCaret( hwnd );
 282     return TRUE;
 283 }
 284
 285
 286 /***********************************************************************
 287  *           EndPaint32    (USER32.176)
 288  */
 289 BOOL WINAPI EndPaint( HWND hwnd, const PAINTSTRUCT *lps )
 290 {
 291     ReleaseDC( hwnd, lps->hdc );
 292     ShowCaret( hwnd );
 293     return TRUE;
 294 }
 295
 296
 297 /***********************************************************************
 298  *           FillWindow    (USER.324)
 299  */
 300 void WINAPI FillWindow16( HWND16 hwndParent, HWND16 hwnd, HDC16 hdc, HBRUSH16 hbrush )
 301 {
 302     RECT16 rect;
 303     GetClientRect16( hwnd, &rect );
 304     DPtoLP16( hdc, (LPPOINT16)&rect, 2 );
 305     PaintRect16( hwndParent, hwnd, hdc, hbrush, &rect );
 306 }
 307
 308
 309 /***********************************************************************
 310  *           PAINT_GetControlBrush
 311  */
 312 static HBRUSH16 PAINT_GetControlBrush( HWND hParent, HWND hWnd, HDC16 hDC, UINT16 ctlType )
 313 {
 314     HBRUSH16 bkgBrush = (HBRUSH16)SendMessageA( hParent, WM_CTLCOLORMSGBOX + ctlType,
 315                                                              (WPARAM)hDC, (LPARAM)hWnd );
 316     if( !IsGDIObject16(bkgBrush) )
 317         bkgBrush = DEFWND_ControlColor( hDC, ctlType );
 318     return bkgBrush;
 319 }
 320
 321
 322 /***********************************************************************
 323  *           PaintRect    (USER.325)
 324  */
 325 void WINAPI PaintRect16( HWND16 hwndParent, HWND16 hwnd, HDC16 hdc,
 326                        HBRUSH16 hbrush, const RECT16 *rect)
 327 {
 328     if( hbrush <= CTLCOLOR_MAX )
 329     {
 330         if( hwndParent )
 331             hbrush = PAINT_GetControlBrush( hwndParent, hwnd, hdc, (UINT16)hbrush );
 332         else
 333             return;
 334     }
 335     if( hbrush )
 336         FillRect16( hdc, rect, hbrush );
 337 }
 338
 339
 340 /***********************************************************************
 341  *           GetControlBrush    (USER.326)
 342  */
 343 HBRUSH16 WINAPI GetControlBrush16( HWND16 hwnd, HDC16 hdc, UINT16 ctlType )
 344 {
 345     WND* wndPtr = WIN_FindWndPtr( hwnd );
 346     HBRUSH16 retvalue;
 347
 348     if((ctlType <= CTLCOLOR_MAX) && wndPtr )
 349     {
 350         WND* parent;
 351         if( wndPtr->dwStyle & WS_POPUP ) parent = WIN_LockWndPtr(wndPtr->owner);
 352         else parent = WIN_LockWndPtr(wndPtr->parent);
 353         if( !parent ) parent = wndPtr;
 354         retvalue = (HBRUSH16)PAINT_GetControlBrush( parent->hwndSelf, hwnd, hdc, ctlType );
 355         WIN_ReleaseWndPtr(parent);
 356         goto END;
 357     }
 358     retvalue = (HBRUSH16)0;
 359 END:
 360     WIN_ReleaseWndPtr(wndPtr);
 361     return retvalue;
 362 }
 363
 364 int i;
 365
 366 /***********************************************************************
 367  *              RDW_UpdateRgns [RedrawWindow() helper]
 368  *
 369  *  Walks the window tree and adds/removes parts of the hRgn to/from update
 370  *  regions of windows that overlap it. Also, manages internal paint flags.
 371  *
 372  *  NOTE: Walks the window tree so the caller must lock it.
 373  *        MUST preserve hRgn (can modify but then has to restore).
 374  */
 375 static void RDW_UpdateRgns( WND* wndPtr, HRGN hRgn, UINT flags )
 376 {
 377     /*
 378      * Called only when one of the following is set:
 379      * (RDW_INVALIDATE | RDW_VALIDATE | RDW_INTERNALPAINT | RDW_NOINTERNALPAINT)
 380      */
 381
 382     BOOL bHadOne =  wndPtr->hrgnUpdate && hRgn;
 383     RECT r = {0, 0, wndPtr->rectWindow.right - wndPtr->rectWindow.left,
 384                     wndPtr->rectWindow.bottom - wndPtr->rectWindow.top };
 385     BOOL bChildren =  ( wndPtr->child && !(flags & RDW_NOCHILDREN) && !(wndPtr->dwStyle & WS_MINIMIZE)
 386                         && ((flags & RDW_ALLCHILDREN) || !(wndPtr->dwStyle & WS_CLIPCHILDREN)) );
 387
 388     TRACE_(win)("\thwnd %04x [%04x] -> hrgn [%04x], flags [%04x]\n", wndPtr->hwndSelf, wndPtr->hrgnUpdate, hRgn, flags );
 389
 390     if( flags & RDW_INVALIDATE )
 391     {
 392         if( hRgn > 1 )
 393         {
 394             switch( wndPtr->hrgnUpdate )
 395             {
 396                 default:
 397                         CombineRgn( wndPtr->hrgnUpdate, wndPtr->hrgnUpdate, hRgn, RGN_OR );
 398                         /* fall through */
 399                 case 0:
 400                         wndPtr->hrgnUpdate = REGION_CropRgn( wndPtr->hrgnUpdate,
 401                                                              wndPtr->hrgnUpdate ? wndPtr->hrgnUpdate : hRgn,
 402                                                              &r, NULL );
 403                         if( !bHadOne )
 404                         {
 405                             GetRgnBox( wndPtr->hrgnUpdate, &r );
 406                             if( IsRectEmpty( &r ) )
 407                             {
 408                                 DeleteObject( wndPtr->hrgnUpdate );
 409                                 wndPtr->hrgnUpdate = 0;
 410                                 goto OUT;
 411                             }
 412                         }
 413                         break;
 414
 415                 case 1: /* already an entire window */
 416             }
 417         }
 418         else if( hRgn == 1 )
 419         {
 420             if( wndPtr->hrgnUpdate > 1 )
 421                 DeleteObject( wndPtr->hrgnUpdate );
 422             wndPtr->hrgnUpdate = 1;
 423         }
 424         else
 425             hRgn = wndPtr->hrgnUpdate;  /* this is a trick that depends on code in PAINT_RedrawWindow() */
 426
 427         if( !bHadOne && !(wndPtr->flags & WIN_INTERNAL_PAINT) )
 428             QUEUE_IncPaintCount( wndPtr->hmemTaskQ );
 429
 430         if (flags & RDW_FRAME) wndPtr->flags |= WIN_NEEDS_NCPAINT;
 431         if (flags & RDW_ERASE) wndPtr->flags |= WIN_NEEDS_ERASEBKGND;
 432         flags    |= RDW_FRAME;
 433     }
 434     else if( flags & RDW_VALIDATE )
 435     {
 436         if( wndPtr->hrgnUpdate )
 437         {
 438             if( hRgn > 1 )
 439             {
 440                 if( wndPtr->hrgnUpdate == 1 )
 441                     wndPtr->hrgnUpdate = CreateRectRgnIndirect( &r );
 442
 443                 if( CombineRgn( wndPtr->hrgnUpdate, wndPtr->hrgnUpdate, hRgn, RGN_DIFF )
 444                     == NULLREGION )
 445                     goto EMPTY;
 446             }
 447             else /* validate everything */
 448             {
 449                 if( wndPtr->hrgnUpdate > 1 )
 450                 {
 451 EMPTY:
 452                     DeleteObject( wndPtr->hrgnUpdate );
 453                 }
 454                 wndPtr->hrgnUpdate = 0;
 455             }
 456
 457             if( !wndPtr->hrgnUpdate )
 458             {
 459                 wndPtr->flags &= ~WIN_NEEDS_ERASEBKGND;
 460                 if( !(wndPtr->flags & WIN_INTERNAL_PAINT) )
 461                     QUEUE_DecPaintCount( wndPtr->hmemTaskQ );
 462             }
 463         }
 464
 465         if (flags & RDW_NOFRAME) wndPtr->flags &= ~WIN_NEEDS_NCPAINT;
 466         if (flags & RDW_NOERASE) wndPtr->flags &= ~WIN_NEEDS_ERASEBKGND;
 467     }
 468
 469     /* in/validate child windows that intersect with the region if it
 470      * is a valid handle. */
 471
 472     if( flags & (RDW_INVALIDATE | RDW_VALIDATE) )
 473     {
 474         if( hRgn > 1 && bChildren )
 475         {
 476             WND* wnd = wndPtr->child;
 477             POINT ptClient = { wndPtr->rectClient.left - wndPtr->rectWindow.left,
 478                                wndPtr->rectClient.top - wndPtr->rectWindow.top };
 479             POINT ptTotal, prevOrigin = {0,0};
 480
 481             for( ptTotal.x = ptTotal.y = 0; wnd; wnd = wnd->next )
 482             {
 483                 if( wnd->dwStyle & WS_VISIBLE )
 484                 {
 485                     POINT ptOffset;
 486
 487                     r.left = wnd->rectWindow.left + ptClient.x;
 488                     r.right = wnd->rectWindow.right + ptClient.x;
 489                     r.top = wnd->rectWindow.top + ptClient.y;
 490                     r.bottom = wnd->rectWindow.bottom + ptClient.y;
 491
 492                     ptOffset.x = r.left - prevOrigin.x;
 493                     ptOffset.y = r.top - prevOrigin.y;
 494                     OffsetRect( &r, -ptTotal.x, -ptTotal.y );
 495
 496                     if( RectInRegion( hRgn, &r ) )
 497                     {
 498                         OffsetRgn( hRgn, -ptOffset.x, -ptOffset.y );
 499                         RDW_UpdateRgns( wnd, hRgn, flags );
 500                         prevOrigin.x = r.left + ptTotal.x;
 501                         prevOrigin.y = r.top + ptTotal.y;
 502                         ptTotal.x += ptOffset.x;
 503                         ptTotal.y += ptOffset.y;
 504                     }
 505                 }
 506             }
 507             OffsetRgn( hRgn, ptTotal.x, ptTotal.y );
 508             bChildren = 0;
 509         }
 510     }
 511
 512     /* handle hRgn == 1 (alias for entire window) and/or internal paint recursion */
 513
 514     if( bChildren )
 515     {
 516         WND* wnd;
 517         for( wnd = wndPtr->child; wnd; wnd = wnd->next )
 518              if( wnd->dwStyle & WS_VISIBLE )
 519                  RDW_UpdateRgns( wnd, hRgn, flags );
 520     }
 521
 522 OUT:
 523
 524     /* Set/clear internal paint flag */
 525
 526     if (flags & RDW_INTERNALPAINT)
 527     {
 528         if ( !wndPtr->hrgnUpdate && !(wndPtr->flags & WIN_INTERNAL_PAINT))
 529             QUEUE_IncPaintCount( wndPtr->hmemTaskQ );
 530         wndPtr->flags |= WIN_INTERNAL_PAINT;
 531     }
 532     else if (flags & RDW_NOINTERNALPAINT)
 533     {
 534         if ( !wndPtr->hrgnUpdate && (wndPtr->flags & WIN_INTERNAL_PAINT))
 535             QUEUE_DecPaintCount( wndPtr->hmemTaskQ );
 536         wndPtr->flags &= ~WIN_INTERNAL_PAINT;
 537     }
 538 }
 539
 540 /***********************************************************************
 541  *           RDW_Paint [RedrawWindow() helper]
 542  *
 543  * Walks the window tree and paints/erases windows that have
 544  * nonzero update regions according to redraw flags. hrgn is a scratch
 545  * region passed down during recursion. Must not be 1.
 546  *
 547  */
 548 static HRGN RDW_Paint( WND* wndPtr, HRGN hrgn, UINT flags, UINT ex )
 549 {
 550 /* NOTE: wndPtr is locked by caller.
 551  *
 552  * FIXME: Windows uses WM_SYNCPAINT to cut down the number of intertask
 553  * SendMessage() calls. This is a comment inside DefWindowProc() source
 554  * from 16-bit SDK:
 555  *
 556  *   This message avoids lots of inter-app message traffic
 557  *   by switching to the other task and continuing the
 558  *   recursion there.
 559  *
 560  * wParam         = flags
 561  * LOWORD(lParam) = hrgnClip
 562  * HIWORD(lParam) = hwndSkip  (not used; always NULL)
 563  *
 564  */
 565     HDC  hDC;
 566     HWND hWnd = wndPtr->hwndSelf;
 567     BOOL bIcon = ((wndPtr->dwStyle & WS_MINIMIZE) && GetClassWord(wndPtr->hwndSelf, GCW_HICON));
 568
 569       /* Erase/update the window itself ... */
 570
 571     TRACE_(win)("\thwnd %04x [%04x] -> hrgn [%04x], flags [%04x]\n", hWnd, wndPtr->hrgnUpdate, hrgn, flags );
 572
 573     if (flags & RDW_UPDATENOW)
 574     {
 575         if (wndPtr->hrgnUpdate) /* wm_painticon wparam is 1 */
 576             SendMessage16( hWnd, (bIcon) ? WM_PAINTICON : WM_PAINT, bIcon, 0 );
 577     }
 578     else if ((flags & RDW_ERASENOW) || (ex & RDW_EX_TOPFRAME))
 579     {
 580         UINT dcx = DCX_INTERSECTRGN | DCX_USESTYLE | DCX_KEEPCLIPRGN | DCX_WINDOWPAINT | DCX_CACHE;
 581         HRGN hrgnRet = WIN_UpdateNCRgn( wndPtr, hrgn, UNC_REGION | UNC_CHECK |
 582                             ((ex & RDW_EX_TOPFRAME) ? UNC_ENTIRE : 0) );
 583         if( hrgnRet )
 584         {
 585             if( hrgnRet > 1 ) hrgn = hrgnRet; else hrgnRet = 0; /* entire client */
 586             if( wndPtr->flags & WIN_NEEDS_ERASEBKGND )
 587             {
 588                 if( bIcon ) dcx |= DCX_WINDOW;
 589                 else
 590                 if( hrgnRet )
 591                     OffsetRgn( hrgnRet, wndPtr->rectWindow.left - wndPtr->rectClient.left,
 592                                         wndPtr->rectWindow.top  - wndPtr->rectClient.top);
 593                 else
 594                     dcx &= ~DCX_INTERSECTRGN;
 595                 if (( hDC = GetDCEx( hWnd, hrgnRet, dcx )) )
 596                 {
 597                     if (SendMessage16( hWnd, (bIcon) ? WM_ICONERASEBKGND
 598                                        : WM_ERASEBKGND, (WPARAM16)hDC, 0 ))
 599                     wndPtr->flags &= ~WIN_NEEDS_ERASEBKGND;
 600                     ReleaseDC( hWnd, hDC );
 601                 }
 602             }
 603         }
 604     }
 605
 606     if( !IsWindow(hWnd) ) return hrgn;
 607     ex &= ~RDW_EX_TOPFRAME;
 608
 609       /* ... and its child windows */
 610
 611     if( wndPtr->child && !(flags & RDW_NOCHILDREN) && !(wndPtr->dwStyle & WS_MINIMIZE)
 612         && ((flags & RDW_ALLCHILDREN) || !(wndPtr->dwStyle & WS_CLIPCHILDREN)) )
 613     {
 614         WND** list, **ppWnd;
 615
 616         if( (list = WIN_BuildWinArray( wndPtr, 0, NULL )) )
 617         {
 618             wndPtr = NULL;
 619             for (ppWnd = list; *ppWnd; ppWnd++)
 620             {
 621                 WIN_UpdateWndPtr(&wndPtr,*ppWnd);
 622                 if (!IsWindow(wndPtr->hwndSelf)) continue;
 623                     if ( (wndPtr->dwStyle & WS_VISIBLE) &&
 624                          (wndPtr->hrgnUpdate || (wndPtr->flags & WIN_INTERNAL_PAINT)) )
 625                         hrgn = RDW_Paint( wndPtr, hrgn, flags, ex );
 626             }
 627             WIN_ReleaseWndPtr(wndPtr);
 628             WIN_ReleaseWinArray(list);
 629         }
 630     }
 631
 632     return hrgn;
 633 }
 634
 635 /***********************************************************************
 636  *           PAINT_RedrawWindow
 637  *
 638  */
 639 BOOL PAINT_RedrawWindow( HWND hwnd, const RECT *rectUpdate,
 640                            HRGN hrgnUpdate, UINT flags, UINT ex )
 641 {
 642     HRGN hRgn = 0;
 643     RECT r, r2;
 644     POINT pt;
 645     WND* wndPtr;
 646
 647     if (!hwnd) hwnd = GetDesktopWindow();
 648     if (!(wndPtr = WIN_FindWndPtr( hwnd ))) return FALSE;
 649
 650     /* check if the window or its parents are visible/not minimized */
 651
 652     if (!WIN_IsWindowDrawable( wndPtr, !(flags & RDW_FRAME) ) )
 653     {
 654         WIN_ReleaseWndPtr(wndPtr);
 655         return TRUE;
 656     }
 657
 658     if (TRACE_ON(win))
 659     {
 660         if( hrgnUpdate )
 661         {
 662             GetRgnBox( hrgnUpdate, &r );
 663             TRACE_(win)( "%04x (%04x) NULL %04x box (%i,%i-%i,%i) flags=%04x, exflags=%04x\n",
 664                   hwnd, wndPtr->hrgnUpdate, hrgnUpdate, r.left, r.top, r.right, r.bottom, flags, ex);
 665         }
 666         else
 667         {
 668             if( rectUpdate )
 669                 r = *rectUpdate;
 670             else
 671                 SetRectEmpty( &r );
 672             TRACE_(win)( "%04x (%04x) %s %d,%d-%d,%d %04x flags=%04x, exflags=%04x\n",
 673                         hwnd, wndPtr->hrgnUpdate, rectUpdate ? "rect" : "NULL", r.left,
 674                         r.top, r.right, r.bottom, hrgnUpdate, flags, ex );
 675         }
 676     }
 677
 678     /* prepare an update region in window coordinates */
 679
 680     if( flags & RDW_FRAME )
 681         r = wndPtr->rectWindow;
 682     else
 683         r = wndPtr->rectClient;
 684
 685     if( ex & RDW_EX_XYWINDOW )
 686     {
 687         pt.x = pt.y = 0;
 688         OffsetRect( &r, -wndPtr->rectWindow.left, -wndPtr->rectWindow.top );
 689     }
 690     else
 691     {
 692         pt.x = wndPtr->rectClient.left - wndPtr->rectWindow.left;
 693         pt.y = wndPtr->rectClient.top - wndPtr->rectWindow.top;
 694         OffsetRect( &r, -wndPtr->rectClient.left, -wndPtr->rectClient.top );
 695     }
 696
 697     if (flags & RDW_INVALIDATE)  /* ------------------------- Invalidate */
 698     {
 699         /* If the window doesn't have hrgnUpdate we leave hRgn zero
 700          * and put a new region straight into wndPtr->hrgnUpdate
 701          * so that RDW_UpdateRgns() won't have to do any extra work.
 702          */
 703
 704         if( hrgnUpdate )
 705         {
 706             if( wndPtr->hrgnUpdate )
 707                 hRgn = REGION_CropRgn( 0, hrgnUpdate, NULL, &pt );
 708             else
 709                 wndPtr->hrgnUpdate = REGION_CropRgn( 0, hrgnUpdate, &r, &pt );
 710         }
 711         else if( rectUpdate )
 712         {
 713             if( !IntersectRect( &r2, &r, rectUpdate ) ) goto END;
 714             OffsetRect( &r2, pt.x, pt.y );
 715
 716 rect2i:
 717             if( wndPtr->hrgnUpdate == 0 )
 718                 wndPtr->hrgnUpdate = CreateRectRgnIndirect( &r2 );
 719             else
 720                 hRgn = CreateRectRgnIndirect( &r2 );
 721         }
 722         else /* entire window or client depending on RDW_FRAME */
 723         {
 724             if( flags & RDW_FRAME )
 725             {
 726                 if( wndPtr->hrgnUpdate )
 727                     DeleteObject( wndPtr->hrgnUpdate );
 728                 wndPtr->hrgnUpdate = 1;
 729             }
 730             else
 731             {
 732                 GETCLIENTRECTW( wndPtr, r2 );
 733                 goto rect2i;
 734             }
 735         }
 736     }
 737     else if (flags & RDW_VALIDATE)  /* ------------------------- Validate */
 738     {
 739         /* In this we cannot leave with zero hRgn */
 740         if( hrgnUpdate )
 741         {
 742             hRgn = REGION_CropRgn( hRgn, hrgnUpdate,  &r, &pt );
 743             GetRgnBox( hRgn, &r2 );
 744             if( IsRectEmpty( &r2 ) ) goto END;
 745         }
 746         else if( rectUpdate )
 747         {
 748             if( !IntersectRect( &r2, &r, rectUpdate ) ) goto END;
 749                 OffsetRect( &r2, pt.x, pt.y );
 750 rect2v:
 751             hRgn = CreateRectRgnIndirect( &r2 );
 752         }
 753         else /* entire window or client depending on RDW_FRAME */
 754         {
 755             if( flags & RDW_FRAME )
 756                 hRgn = 1;
 757             else
 758             {
 759                 GETCLIENTRECTW( wndPtr, r2 );
 760                 goto rect2v;
 761             }
 762         }
 763     }
 764
 765     /* At this point hRgn is either an update region in window coordinates or 1 or 0 */
 766
 767     RDW_UpdateRgns( wndPtr, hRgn, flags );
 768
 769     /* Erase/update windows, from now on hRgn is a scratch region */
 770
 771     hRgn = RDW_Paint( wndPtr, (hRgn == 1) ? 0 : hRgn, flags, ex );
 772
 773 END:
 774     if( hRgn > 1 && (hRgn != hrgnUpdate) )
 775         DeleteObject(hRgn );
 776     WIN_ReleaseWndPtr(wndPtr);
 777     return TRUE;
 778 }
 779
 780
 781 /***********************************************************************
 782  *           RedrawWindow32    (USER32.426)
 783  */
 784 BOOL WINAPI RedrawWindow( HWND hwnd, const RECT *rectUpdate,
 785                               HRGN hrgnUpdate, UINT flags )
 786 {
 787     return PAINT_RedrawWindow( hwnd, rectUpdate, hrgnUpdate, flags, 0 );
 788 }
 789
 790
 791 /***********************************************************************
 792  *           RedrawWindow16    (USER.290)
 793  */
 794 BOOL16 WINAPI RedrawWindow16( HWND16 hwnd, const RECT16 *rectUpdate,
 795                               HRGN16 hrgnUpdate, UINT16 flags )
 796 {
 797     if (rectUpdate)
 798     {
 799         RECT r;
 800         CONV_RECT16TO32( rectUpdate, &r );
 801         return (BOOL16)RedrawWindow( (HWND)hwnd, &r, hrgnUpdate, flags );
 802     }
 803     return (BOOL16)PAINT_RedrawWindow( (HWND)hwnd, NULL,
 804                                        (HRGN)hrgnUpdate, flags, 0 );
 805 }
 806
 807
 808 /***********************************************************************
 809  *           UpdateWindow16   (USER.124)
 810  */
 811 void WINAPI UpdateWindow16( HWND16 hwnd )
 812 {
 813     PAINT_RedrawWindow( hwnd, NULL, 0, RDW_UPDATENOW | RDW_NOCHILDREN, 0 );
 814 }
 815
 816 /***********************************************************************
 817  *           UpdateWindow32   (USER32.567)
 818  */
 819 void WINAPI UpdateWindow( HWND hwnd )
 820 {
 821     PAINT_RedrawWindow( hwnd, NULL, 0, RDW_UPDATENOW | RDW_NOCHILDREN, 0 );
 822 }
 823
 824 /***********************************************************************
 825  *           InvalidateRgn16   (USER.126)
 826  */
 827 void WINAPI InvalidateRgn16( HWND16 hwnd, HRGN16 hrgn, BOOL16 erase )
 828 {
 829     PAINT_RedrawWindow((HWND)hwnd, NULL, (HRGN)hrgn,
 830                        RDW_INVALIDATE | (erase ? RDW_ERASE : 0), 0 );
 831 }
 832
 833
 834 /***********************************************************************
 835  *           InvalidateRgn32   (USER32.329)
 836  */
 837 BOOL WINAPI InvalidateRgn( HWND hwnd, HRGN hrgn, BOOL erase )
 838 {
 839     return PAINT_RedrawWindow(hwnd, NULL, hrgn, RDW_INVALIDATE | (erase ? RDW_ERASE : 0), 0 );
 840 }
 841
 842
 843 /***********************************************************************
 844  *           InvalidateRect16   (USER.125)
 845  */
 846 void WINAPI InvalidateRect16( HWND16 hwnd, const RECT16 *rect, BOOL16 erase )
 847 {
 848     RedrawWindow16( hwnd, rect, 0, RDW_INVALIDATE | (erase ? RDW_ERASE : 0) );
 849 }
 850
 851
 852 /***********************************************************************
 853  *           InvalidateRect32   (USER32.328)
 854  */
 855 BOOL WINAPI InvalidateRect( HWND hwnd, const RECT *rect, BOOL erase )
 856 {
 857     return PAINT_RedrawWindow( hwnd, rect, 0,
 858                                RDW_INVALIDATE | (erase ? RDW_ERASE : 0), 0 );
 859 }
 860
 861
 862 /***********************************************************************
 863  *           ValidateRgn16   (USER.128)
 864  */
 865 void WINAPI ValidateRgn16( HWND16 hwnd, HRGN16 hrgn )
 866 {
 867     PAINT_RedrawWindow( (HWND)hwnd, NULL, (HRGN)hrgn,
 868                         RDW_VALIDATE | RDW_NOCHILDREN, 0 );
 869 }
 870
 871
 872 /***********************************************************************
 873  *           ValidateRgn32   (USER32.572)
 874  */
 875 void WINAPI ValidateRgn( HWND hwnd, HRGN hrgn )
 876 {
 877     PAINT_RedrawWindow( hwnd, NULL, hrgn, RDW_VALIDATE | RDW_NOCHILDREN, 0 );
 878 }
 879
 880
 881 /***********************************************************************
 882  *           ValidateRect16   (USER.127)
 883  */
 884 void WINAPI ValidateRect16( HWND16 hwnd, const RECT16 *rect )
 885 {
 886     RedrawWindow16( hwnd, rect, 0, RDW_VALIDATE | RDW_NOCHILDREN );
 887 }
 888
 889
 890 /***********************************************************************
 891  *           ValidateRect32   (USER32.571)
 892  */
 893 void WINAPI ValidateRect( HWND hwnd, const RECT *rect )
 894 {
 895     PAINT_RedrawWindow( hwnd, rect, 0, RDW_VALIDATE | RDW_NOCHILDREN, 0 );
 896 }
 897
 898
 899 /***********************************************************************
 900  *           GetUpdateRect16   (USER.190)
 901  */
 902 BOOL16 WINAPI GetUpdateRect16( HWND16 hwnd, LPRECT16 rect, BOOL16 erase )
 903 {
 904     RECT r;
 905     BOOL16 ret;
 906
 907     if (!rect) return GetUpdateRect( hwnd, NULL, erase );
 908     ret = GetUpdateRect( hwnd, &r, erase );
 909     CONV_RECT32TO16( &r, rect );
 910     return ret;
 911 }
 912
 913
 914 /***********************************************************************
 915  *           GetUpdateRect32   (USER32.297)
 916  */
 917 BOOL WINAPI GetUpdateRect( HWND hwnd, LPRECT rect, BOOL erase )
 918 {
 919     BOOL retvalue;
 920     WND * wndPtr = WIN_FindWndPtr( hwnd );
 921     if (!wndPtr) return FALSE;
 922
 923     if (rect)
 924     {
 925         if (wndPtr->hrgnUpdate > 1)
 926         {
 927             HRGN hrgn = CreateRectRgn( 0, 0, 0, 0 );
 928             if (GetUpdateRgn( hwnd, hrgn, erase ) == ERROR)
 929             {
 930                 retvalue = FALSE;
 931                 goto END;
 932             }
 933             GetRgnBox( hrgn, rect );
 934             DeleteObject( hrgn );
 935             if (GetClassLongA(wndPtr->hwndSelf, GCL_STYLE) & CS_OWNDC)
 936             {
 937                 if (GetMapMode(wndPtr->dce->hDC) != MM_TEXT)
 938                 {
 939                     DPtoLP (wndPtr->dce->hDC, (LPPOINT)rect,  2);
 940                 }
 941             }
 942         }
 943         else
 944         if( wndPtr->hrgnUpdate == 1 )
 945         {
 946             GetClientRect( hwnd, rect );
 947             if (erase) RedrawWindow( hwnd, NULL, 0, RDW_FRAME | RDW_ERASENOW | RDW_NOCHILDREN );
 948         }
 949         else
 950             SetRectEmpty( rect );
 951     }
 952     retvalue = (wndPtr->hrgnUpdate >= 1);
 953 END:
 954     WIN_ReleaseWndPtr(wndPtr);
 955     return retvalue;
 956 }
 957
 958
 959 /***********************************************************************
 960  *           GetUpdateRgn16   (USER.237)
 961  */
 962 INT16 WINAPI GetUpdateRgn16( HWND16 hwnd, HRGN16 hrgn, BOOL16 erase )
 963 {
 964     return GetUpdateRgn( hwnd, hrgn, erase );
 965 }
 966
 967
 968 /***********************************************************************
 969  *           GetUpdateRgn    (USER32.298)
 970  */
 971 INT WINAPI GetUpdateRgn( HWND hwnd, HRGN hrgn, BOOL erase )
 972 {
 973     INT retval;
 974     WND * wndPtr = WIN_FindWndPtr( hwnd );
 975     if (!wndPtr) return ERROR;
 976
 977     if (wndPtr->hrgnUpdate == 0)
 978     {
 979         SetRectRgn( hrgn, 0, 0, 0, 0 );
 980         retval = NULLREGION;
 981         goto END;
 982     }
 983     else
 984     if (wndPtr->hrgnUpdate == 1)
 985     {
 986         SetRectRgn( hrgn, 0, 0, wndPtr->rectClient.right - wndPtr->rectClient.left,
 987                                 wndPtr->rectClient.bottom - wndPtr->rectClient.top );
 988         retval = SIMPLEREGION;
 989     }
 990     else
 991     {
 992         retval = CombineRgn( hrgn, wndPtr->hrgnUpdate, 0, RGN_COPY );
 993         OffsetRgn( hrgn, wndPtr->rectWindow.left - wndPtr->rectClient.left,
 994                          wndPtr->rectWindow.top - wndPtr->rectClient.top );
 995     }
 996     if (erase) RedrawWindow( hwnd, NULL, 0, RDW_ERASENOW | RDW_NOCHILDREN );
 997 END:
 998     WIN_ReleaseWndPtr(wndPtr);
 999     return retval;
1000 }
1001
1002
1003 /***********************************************************************
1004  *           ExcludeUpdateRgn16   (USER.238)
1005  */
1006 INT16 WINAPI ExcludeUpdateRgn16( HDC16 hdc, HWND16 hwnd )
1007 {
1008     return ExcludeUpdateRgn( hdc, hwnd );
1009 }
1010
1011
1012 /***********************************************************************
1013  *           ExcludeUpdateRgn32   (USER32.195)
1014  */
1015 INT WINAPI ExcludeUpdateRgn( HDC hdc, HWND hwnd )
1016 {
1017     RECT rect;
1018     WND * wndPtr;
1019
1020     if (!(wndPtr = WIN_FindWndPtr( hwnd ))) return ERROR;
1021
1022     if (wndPtr->hrgnUpdate)
1023     {
1024         INT ret;
1025         HRGN hrgn = CreateRectRgn(wndPtr->rectWindow.left - wndPtr->rectClient.left,
1026                                       wndPtr->rectWindow.top - wndPtr->rectClient.top,
1027                                       wndPtr->rectWindow.right - wndPtr->rectClient.left,
1028                                       wndPtr->rectWindow.bottom - wndPtr->rectClient.top);
1029         if( wndPtr->hrgnUpdate > 1 )
1030         {
1031             CombineRgn(hrgn, wndPtr->hrgnUpdate, 0, RGN_COPY);
1032             OffsetRgn(hrgn, wndPtr->rectWindow.left - wndPtr->rectClient.left,
1033                             wndPtr->rectWindow.top - wndPtr->rectClient.top );
1034         }
1035
1036         /* do ugly coordinate translations in dce.c */
1037
1038         ret = DCE_ExcludeRgn( hdc, wndPtr, hrgn );
1039         DeleteObject( hrgn );
1040         WIN_ReleaseWndPtr(wndPtr);
1041         return ret;
1042     }
1043     WIN_ReleaseWndPtr(wndPtr);
1044     return GetClipBox( hdc, &rect );
1045 }
1046
1047