dlls/user32/painting.c

   1 /*
   2  * Window painting functions
   3  *
   4  * Copyright 1993, 1994, 1995, 2001, 2004, 2005, 2008 Alexandre Julliard
   5  * Copyright 1996, 1997, 1999 Alex Korobka
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  20  */
  21
  22 #include "config.h"
  23 #include "wine/port.h"
  24
  25 #include <assert.h>
  26 #include <stdarg.h>
  27 #include <string.h>
  28
  29 #include "ntstatus.h"
  30 #define WIN32_NO_STATUS
  31 #include "windef.h"
  32 #include "winbase.h"
  33 #include "wingdi.h"
  34 #include "winuser.h"
  35 #include "wine/server.h"
  36 #include "win.h"
  37 #include "user_private.h"
  38 #include "controls.h"
  39 #include "wine/list.h"
  40 #include "wine/debug.h"
  41
  42 WINE_DEFAULT_DEBUG_CHANNEL(win);
  43
  44
  45 struct dce
  46 {
  47     struct list entry;         /* entry in global DCE list */
  48     HDC         hdc;
  49     HWND        hwnd;
  50     HRGN        clip_rgn;
  51     DWORD       flags;
  52     LONG        count;         /* usage count; 0 or 1 for cache DCEs, always 1 for window DCEs,
  53                                   always >= 1 for class DCEs */
  54 };
  55
  56 static struct list dce_list = LIST_INIT(dce_list);
  57
  58 static BOOL CALLBACK dc_hook( HDC hDC, WORD code, DWORD_PTR data, LPARAM lParam );
  59
  60 static const WCHAR displayW[] = { 'D','I','S','P','L','A','Y',0 };
  61
  62
  63 /***********************************************************************
  64  *           dump_rdw_flags
  65  */
  66 static void dump_rdw_flags(UINT flags)
  67 {
  68     TRACE("flags:");
  69     if (flags & RDW_INVALIDATE) TRACE(" RDW_INVALIDATE");
  70     if (flags & RDW_INTERNALPAINT) TRACE(" RDW_INTERNALPAINT");
  71     if (flags & RDW_ERASE) TRACE(" RDW_ERASE");
  72     if (flags & RDW_VALIDATE) TRACE(" RDW_VALIDATE");
  73     if (flags & RDW_NOINTERNALPAINT) TRACE(" RDW_NOINTERNALPAINT");
  74     if (flags & RDW_NOERASE) TRACE(" RDW_NOERASE");
  75     if (flags & RDW_NOCHILDREN) TRACE(" RDW_NOCHILDREN");
  76     if (flags & RDW_ALLCHILDREN) TRACE(" RDW_ALLCHILDREN");
  77     if (flags & RDW_UPDATENOW) TRACE(" RDW_UPDATENOW");
  78     if (flags & RDW_ERASENOW) TRACE(" RDW_ERASENOW");
  79     if (flags & RDW_FRAME) TRACE(" RDW_FRAME");
  80     if (flags & RDW_NOFRAME) TRACE(" RDW_NOFRAME");
  81
  82 #define RDW_FLAGS \
  83     (RDW_INVALIDATE | \
  84     RDW_INTERNALPAINT | \
  85     RDW_ERASE | \
  86     RDW_VALIDATE | \
  87     RDW_NOINTERNALPAINT | \
  88     RDW_NOERASE | \
  89     RDW_NOCHILDREN | \
  90     RDW_ALLCHILDREN | \
  91     RDW_UPDATENOW | \
  92     RDW_ERASENOW | \
  93     RDW_FRAME | \
  94     RDW_NOFRAME)
  95
  96     if (flags & ~RDW_FLAGS) TRACE(" %04x", flags & ~RDW_FLAGS);
  97     TRACE("\n");
  98 #undef RDW_FLAGS
  99 }
 100
 101
 102 /***********************************************************************
 103  *              update_visible_region
 104  *
 105  * Set the visible region and X11 drawable for the DC associated to
 106  * a given window.
 107  */
 108 static void update_visible_region( struct dce *dce )
 109 {
 110     NTSTATUS status;
 111     HRGN vis_rgn = 0;
 112     HWND top_win = 0;
 113     DWORD flags = dce->flags;
 114     size_t size = 256;
 115     RECT win_rect, top_rect;
 116
 117     /* don't clip siblings if using parent clip region */
 118     if (flags & DCX_PARENTCLIP) flags &= ~DCX_CLIPSIBLINGS;
 119
 120     /* fetch the visible region from the server */
 121     do
 122     {
 123         RGNDATA *data = HeapAlloc( GetProcessHeap(), 0, sizeof(*data) + size - 1 );
 124         if (!data) return;
 125
 126         SERVER_START_REQ( get_visible_region )
 127         {
 128             req->window  = dce->hwnd;
 129             req->flags   = flags;
 130             wine_server_set_reply( req, data->Buffer, size );
 131             if (!(status = wine_server_call( req )))
 132             {
 133                 size_t reply_size = wine_server_reply_size( reply );
 134                 data->rdh.dwSize   = sizeof(data->rdh);
 135                 data->rdh.iType    = RDH_RECTANGLES;
 136                 data->rdh.nCount   = reply_size / sizeof(RECT);
 137                 data->rdh.nRgnSize = reply_size;
 138                 vis_rgn = ExtCreateRegion( NULL, size, data );
 139
 140                 top_win         = reply->top_win;
 141                 win_rect.left   = reply->win_rect.left;
 142                 win_rect.top    = reply->win_rect.top;
 143                 win_rect.right  = reply->win_rect.right;
 144                 win_rect.bottom = reply->win_rect.bottom;
 145                 top_rect.left   = reply->top_rect.left;
 146                 top_rect.top    = reply->top_rect.top;
 147                 top_rect.right  = reply->top_rect.right;
 148                 top_rect.bottom = reply->top_rect.bottom;
 149             }
 150             else size = reply->total_size;
 151         }
 152         SERVER_END_REQ;
 153         HeapFree( GetProcessHeap(), 0, data );
 154     } while (status == STATUS_BUFFER_OVERFLOW);
 155
 156     if (status || !vis_rgn) return;
 157
 158     USER_Driver->pGetDC( dce->hdc, dce->hwnd, top_win, &win_rect, &top_rect, flags );
 159
 160     if (dce->clip_rgn) CombineRgn( vis_rgn, vis_rgn, dce->clip_rgn,
 161                                    (flags & DCX_INTERSECTRGN) ? RGN_AND : RGN_DIFF );
 162
 163     /* map region to DC coordinates */
 164     OffsetRgn( vis_rgn, -win_rect.left, -win_rect.top );
 165     SelectVisRgn( dce->hdc, vis_rgn );
 166     DeleteObject( vis_rgn );
 167 }
 168
 169
 170 /***********************************************************************
 171  *              release_dce
 172  */
 173 static void release_dce( struct dce *dce )
 174 {
 175     if (!dce->hwnd) return;  /* already released */
 176
 177     USER_Driver->pReleaseDC( dce->hwnd, dce->hdc );
 178
 179     if (dce->clip_rgn) DeleteObject( dce->clip_rgn );
 180     dce->clip_rgn = 0;
 181     dce->hwnd     = 0;
 182     dce->flags   &= DCX_CACHE;
 183 }
 184
 185
 186 /***********************************************************************
 187  *   delete_clip_rgn
 188  */
 189 static void delete_clip_rgn( struct dce *dce )
 190 {
 191     if (!dce->clip_rgn) return;  /* nothing to do */
 192
 193     dce->flags &= ~(DCX_EXCLUDERGN | DCX_INTERSECTRGN);
 194     DeleteObject( dce->clip_rgn );
 195     dce->clip_rgn = 0;
 196
 197     /* make it dirty so that the vis rgn gets recomputed next time */
 198     SetHookFlags( dce->hdc, DCHF_INVALIDATEVISRGN );
 199 }
 200
 201
 202 /***********************************************************************
 203  *           alloc_dce
 204  *
 205  * Allocate a new DCE.
 206  */
 207 static struct dce *alloc_dce(void)
 208 {
 209     struct dce *dce;
 210
 211     if (!(dce = HeapAlloc( GetProcessHeap(), 0, sizeof(*dce) ))) return NULL;
 212     if (!(dce->hdc = CreateDCW( displayW, NULL, NULL, NULL )))
 213     {
 214         HeapFree( GetProcessHeap(), 0, dce );
 215         return 0;
 216     }
 217     SaveDC( dce->hdc );
 218
 219     dce->hwnd      = 0;
 220     dce->clip_rgn  = 0;
 221     dce->flags     = 0;
 222     dce->count     = 1;
 223
 224     /* store DCE handle in DC hook data field */
 225     SetDCHook( dce->hdc, dc_hook, (DWORD_PTR)dce );
 226     SetHookFlags( dce->hdc, DCHF_INVALIDATEVISRGN );
 227     return dce;
 228 }
 229
 230
 231 /***********************************************************************
 232  *              get_window_dce
 233  */
 234 static struct dce *get_window_dce( HWND hwnd )
 235 {
 236     struct dce *dce;
 237     WND *win = WIN_GetPtr( hwnd );
 238
 239     if (!win || win == WND_OTHER_PROCESS || win == WND_DESKTOP) return NULL;
 240
 241     dce = win->dce;
 242     if (!dce && (dce = get_class_dce( win->class )))
 243     {
 244         win->dce = dce;
 245         dce->count++;
 246     }
 247     WIN_ReleasePtr( win );
 248
 249     if (!dce)  /* try to allocate one */
 250     {
 251         struct dce *dce_to_free = NULL;
 252         LONG class_style = GetClassLongW( hwnd, GCL_STYLE );
 253
 254         if (class_style & CS_CLASSDC)
 255         {
 256             if (!(dce = alloc_dce())) return NULL;
 257
 258             win = WIN_GetPtr( hwnd );
 259             if (win && win != WND_OTHER_PROCESS && win != WND_DESKTOP)
 260             {
 261                 if (win->dce)  /* another thread beat us to it */
 262                 {
 263                     dce_to_free = dce;
 264                     dce = win->dce;
 265                 }
 266                 else if ((win->dce = set_class_dce( win->class, dce )) != dce)
 267                 {
 268                     dce_to_free = dce;
 269                     dce = win->dce;
 270                     dce->count++;
 271                 }
 272                 else
 273                 {
 274                     dce->count++;
 275                     list_add_tail( &dce_list, &dce->entry );
 276                 }
 277                 WIN_ReleasePtr( win );
 278             }
 279             else dce_to_free = dce;
 280         }
 281         else if (class_style & CS_OWNDC)
 282         {
 283             if (!(dce = alloc_dce())) return NULL;
 284
 285             win = WIN_GetPtr( hwnd );
 286             if (win && win != WND_OTHER_PROCESS && win != WND_DESKTOP)
 287             {
 288                 if (win->dwStyle & WS_CLIPCHILDREN) dce->flags |= DCX_CLIPCHILDREN;
 289                 if (win->dwStyle & WS_CLIPSIBLINGS) dce->flags |= DCX_CLIPSIBLINGS;
 290                 if (win->dce)  /* another thread beat us to it */
 291                 {
 292                     dce_to_free = dce;
 293                     dce = win->dce;
 294                 }
 295                 else
 296                 {
 297                     win->dce = dce;
 298                     dce->hwnd = hwnd;
 299                     list_add_tail( &dce_list, &dce->entry );
 300                 }
 301                 WIN_ReleasePtr( win );
 302             }
 303             else dce_to_free = dce;
 304         }
 305
 306         if (dce_to_free)
 307         {
 308             SetDCHook( dce->hdc, NULL, 0 );
 309             DeleteDC( dce->hdc );
 310             HeapFree( GetProcessHeap(), 0, dce );
 311         }
 312     }
 313     return dce;
 314 }
 315
 316
 317 /***********************************************************************
 318  *           free_dce
 319  *
 320  * Free a class or window DCE.
 321  */
 322 void free_dce( struct dce *dce, HWND hwnd )
 323 {
 324     USER_Lock();
 325
 326     if (dce)
 327     {
 328         if (!--dce->count)
 329         {
 330             /* turn it into a cache entry */
 331             release_dce( dce );
 332             dce->flags |= DCX_CACHE;
 333         }
 334         else if (dce->hwnd == hwnd)
 335         {
 336             release_dce( dce );
 337         }
 338     }
 339
 340     /* now check for cache DCEs */
 341
 342     if (hwnd)
 343     {
 344         LIST_FOR_EACH_ENTRY( dce, &dce_list, struct dce, entry )
 345         {
 346             if (dce->hwnd != hwnd) continue;
 347             if (!(dce->flags & DCX_CACHE)) continue;
 348
 349             if (dce->count) WARN( "GetDC() without ReleaseDC() for window %p\n", hwnd );
 350             dce->count = 0;
 351             release_dce( dce );
 352         }
 353     }
 354
 355     USER_Unlock();
 356 }
 357
 358
 359 /***********************************************************************
 360  *           make_dc_dirty
 361  *
 362  * Mark the associated DC as dirty to force a refresh of the visible region
 363  */
 364 static void make_dc_dirty( struct dce *dce )
 365 {
 366     if (!dce->count)
 367     {
 368         /* Don't bother with visible regions of unused DCEs */
 369         TRACE("\tpurged %p dce [%p]\n", dce, dce->hwnd);
 370         release_dce( dce );
 371     }
 372     else
 373     {
 374         /* Set dirty bits in the hDC and DCE structs */
 375         TRACE("\tfixed up %p dce [%p]\n", dce, dce->hwnd);
 376         SetHookFlags( dce->hdc, DCHF_INVALIDATEVISRGN );
 377     }
 378 }
 379
 380
 381 /***********************************************************************
 382  *   invalidate_dce
 383  *
 384  * It is called from SetWindowPos() - we have to
 385  * mark as dirty all busy DCEs for windows that have pWnd->parent as
 386  * an ancestor and whose client rect intersects with specified update
 387  * rectangle. In addition, pWnd->parent DCEs may need to be updated if
 388  * DCX_CLIPCHILDREN flag is set.
 389  */
 390 void invalidate_dce( HWND hwnd, const RECT *rect )
 391 {
 392     RECT window_rect, extra_rect;
 393     struct dce *dce;
 394     HWND hwndScope = GetAncestor( hwnd, GA_PARENT );
 395
 396     if (!hwndScope) return;
 397
 398     GetWindowRect( hwnd, &window_rect );
 399     if (rect)
 400     {
 401         extra_rect = *rect;
 402         MapWindowPoints( hwndScope, 0, (POINT *)&extra_rect, 2 );
 403     }
 404
 405     TRACE("%p scope hwnd = %p %s (%s)\n",
 406           hwnd, hwndScope, wine_dbgstr_rect(&window_rect), wine_dbgstr_rect(rect) );
 407
 408     /* walk all DCEs and fixup non-empty entries */
 409
 410     USER_Lock();
 411     LIST_FOR_EACH_ENTRY( dce, &dce_list, struct dce, entry )
 412     {
 413         TRACE( "%p: hwnd %p dcx %08x %s %s\n", dce, dce->hwnd, dce->flags,
 414                (dce->flags & DCX_CACHE) ? "Cache" : "Owned", dce->count ? "InUse" : "" );
 415
 416         if (!dce->hwnd) continue;
 417         if ((dce->hwnd == hwndScope) && !(dce->flags & DCX_CLIPCHILDREN))
 418             continue;  /* child window positions don't bother us */
 419
 420         /* if DCE window is a child of hwnd, it has to be invalidated */
 421         if (dce->hwnd == hwnd || IsChild( hwnd, dce->hwnd ))
 422         {
 423             make_dc_dirty( dce );
 424         }
 425         else  /* otherwise check if the window rectangle intersects this DCE window */
 426         {
 427             if (hwndScope == GetDesktopWindow() ||
 428                 hwndScope == dce->hwnd || IsChild( hwndScope, dce->hwnd ))
 429             {
 430                 RECT dce_rect, tmp;
 431                 GetWindowRect( dce->hwnd, &dce_rect );
 432                 if (IntersectRect( &tmp, &dce_rect, &window_rect ) ||
 433                     (rect && IntersectRect( &tmp, &dce_rect, &extra_rect )))
 434                     make_dc_dirty( dce );
 435             }
 436         }
 437     }
 438     USER_Unlock();
 439 }
 440
 441 /***********************************************************************
 442  *              release_dc
 443  *
 444  * Implementation of ReleaseDC.
 445  */
 446 static INT release_dc( HWND hwnd, HDC hdc, BOOL end_paint )
 447 {
 448     struct dce *dce;
 449     BOOL ret = FALSE;
 450
 451     TRACE("%p %p\n", hwnd, hdc );
 452
 453     USER_Lock();
 454     dce = (struct dce *)GetDCHook( hdc, NULL );
 455     if (dce && dce->count)
 456     {
 457         if (end_paint || (dce->flags & DCX_CACHE)) delete_clip_rgn( dce );
 458         if (dce->flags & DCX_CACHE) dce->count = 0;
 459         ret = TRUE;
 460     }
 461     USER_Unlock();
 462     return ret;
 463 }
 464
 465
 466 /***********************************************************************
 467  *              dc_hook
 468  *
 469  * See "Undoc. Windows" for hints (DC, SetDCHook, SetHookFlags)..
 470  */
 471 static BOOL CALLBACK dc_hook( HDC hDC, WORD code, DWORD_PTR data, LPARAM lParam )
 472 {
 473     BOOL retv = TRUE;
 474     struct dce *dce = (struct dce *)data;
 475
 476     TRACE("hDC = %p, %u\n", hDC, code);
 477
 478     if (!dce) return 0;
 479     assert( dce->hdc == hDC );
 480
 481     switch( code )
 482     {
 483     case DCHC_INVALIDVISRGN:
 484         /* GDI code calls this when it detects that the
 485          * DC is dirty (usually after SetHookFlags()). This
 486          * means that we have to recompute the visible region.
 487          */
 488         if (dce->count) update_visible_region( dce );
 489         else /* non-fatal but shouldn't happen */
 490             WARN("DC is not in use!\n");
 491         break;
 492     case DCHC_DELETEDC:
 493         /*
 494          * Windows will not let you delete a DC that is busy
 495          * (between GetDC and ReleaseDC)
 496          */
 497         USER_Lock();
 498         if (dce->count)
 499         {
 500             WARN("Application trying to delete a busy DC %p\n", dce->hdc);
 501             retv = FALSE;
 502         }
 503         else
 504         {
 505             list_remove( &dce->entry );
 506             if (dce->clip_rgn) DeleteObject( dce->clip_rgn );
 507             HeapFree( GetProcessHeap(), 0, dce );
 508         }
 509         USER_Unlock();
 510         break;
 511     }
 512     return retv;
 513 }
 514
 515
 516 /***********************************************************************
 517  *           get_update_region
 518  *
 519  * Return update region (in screen coordinates) for a window.
 520  */
 521 static HRGN get_update_region( HWND hwnd, UINT *flags, HWND *child )
 522 {
 523     HRGN hrgn = 0;
 524     NTSTATUS status;
 525     RGNDATA *data;
 526     size_t size = 256;
 527
 528     do
 529     {
 530         if (!(data = HeapAlloc( GetProcessHeap(), 0, sizeof(*data) + size - 1 )))
 531         {
 532             SetLastError( ERROR_OUTOFMEMORY );
 533             return 0;
 534         }
 535
 536         SERVER_START_REQ( get_update_region )
 537         {
 538             req->window     = hwnd;
 539             req->from_child = child ? *child : 0;
 540             req->flags      = *flags;
 541             wine_server_set_reply( req, data->Buffer, size );
 542             if (!(status = wine_server_call( req )))
 543             {
 544                 size_t reply_size = wine_server_reply_size( reply );
 545                 data->rdh.dwSize   = sizeof(data->rdh);
 546                 data->rdh.iType    = RDH_RECTANGLES;
 547                 data->rdh.nCount   = reply_size / sizeof(RECT);
 548                 data->rdh.nRgnSize = reply_size;
 549                 hrgn = ExtCreateRegion( NULL, size, data );
 550                 if (child) *child = reply->child;
 551                 *flags = reply->flags;
 552             }
 553             else size = reply->total_size;
 554         }
 555         SERVER_END_REQ;
 556         HeapFree( GetProcessHeap(), 0, data );
 557     } while (status == STATUS_BUFFER_OVERFLOW);
 558
 559     if (status) SetLastError( RtlNtStatusToDosError(status) );
 560     return hrgn;
 561 }
 562
 563
 564 /***********************************************************************
 565  *           get_update_flags
 566  *
 567  * Get only the update flags, not the update region.
 568  */
 569 static BOOL get_update_flags( HWND hwnd, HWND *child, UINT *flags )
 570 {
 571     BOOL ret;
 572
 573     SERVER_START_REQ( get_update_region )
 574     {
 575         req->window     = hwnd;
 576         req->from_child = child ? *child : 0;
 577         req->flags      = *flags | UPDATE_NOREGION;
 578         if ((ret = !wine_server_call_err( req )))
 579         {
 580             if (child) *child = reply->child;
 581             *flags = reply->flags;
 582         }
 583     }
 584     SERVER_END_REQ;
 585     return ret;
 586 }
 587
 588
 589 /***********************************************************************
 590  *           redraw_window_rects
 591  *
 592  * Redraw part of a window.
 593  */
 594 static BOOL redraw_window_rects( HWND hwnd, UINT flags, const RECT *rects, UINT count )
 595 {
 596     BOOL ret;
 597
 598     if (!(flags & (RDW_INVALIDATE|RDW_VALIDATE|RDW_INTERNALPAINT|RDW_NOINTERNALPAINT)))
 599         return TRUE;  /* nothing to do */
 600
 601     SERVER_START_REQ( redraw_window )
 602     {
 603         req->window = hwnd;
 604         req->flags  = flags;
 605         wine_server_add_data( req, rects, count * sizeof(RECT) );
 606         ret = !wine_server_call_err( req );
 607     }
 608     SERVER_END_REQ;
 609     return ret;
 610 }
 611
 612
 613 /***********************************************************************
 614  *           send_ncpaint
 615  *
 616  * Send a WM_NCPAINT message if needed, and return the resulting update region (in screen coords).
 617  * Helper for erase_now and BeginPaint.
 618  */
 619 static HRGN send_ncpaint( HWND hwnd, HWND *child, UINT *flags )
 620 {
 621     HRGN whole_rgn = get_update_region( hwnd, flags, child );
 622     HRGN client_rgn = 0;
 623
 624     if (child) hwnd = *child;
 625
 626     if (whole_rgn)
 627     {
 628         RECT client, update;
 629         INT type;
 630
 631         /* check if update rgn overlaps with nonclient area */
 632         type = GetRgnBox( whole_rgn, &update );
 633         GetClientRect( hwnd, &client );
 634         MapWindowPoints( hwnd, 0, (POINT *)&client, 2 );
 635
 636         if ((*flags & UPDATE_NONCLIENT) ||
 637             update.left < client.left || update.top < client.top ||
 638             update.right > client.right || update.bottom > client.bottom)
 639         {
 640             client_rgn = CreateRectRgnIndirect( &client );
 641             CombineRgn( client_rgn, client_rgn, whole_rgn, RGN_AND );
 642
 643             /* check if update rgn contains complete nonclient area */
 644             if (type == SIMPLEREGION)
 645             {
 646                 RECT window;
 647                 GetWindowRect( hwnd, &window );
 648                 if (EqualRect( &window, &update ))
 649                 {
 650                     DeleteObject( whole_rgn );
 651                     whole_rgn = (HRGN)1;
 652                 }
 653             }
 654         }
 655         else
 656         {
 657             client_rgn = whole_rgn;
 658             whole_rgn = 0;
 659         }
 660
 661         if (whole_rgn) /* NOTE: WM_NCPAINT allows wParam to be 1 */
 662         {
 663             if (*flags & UPDATE_NONCLIENT) SendMessageW( hwnd, WM_NCPAINT, (WPARAM)whole_rgn, 0 );
 664             if (whole_rgn > (HRGN)1) DeleteObject( whole_rgn );
 665         }
 666     }
 667     return client_rgn;
 668 }
 669
 670
 671 /***********************************************************************
 672  *           send_erase
 673  *
 674  * Send a WM_ERASEBKGND message if needed, and optionally return the DC for painting.
 675  * If a DC is requested, the region is selected into it. In all cases the region is deleted.
 676  * Helper for erase_now and BeginPaint.
 677  */
 678 static BOOL send_erase( HWND hwnd, UINT flags, HRGN client_rgn,
 679                         RECT *clip_rect, HDC *hdc_ret )
 680 {
 681     BOOL need_erase = (flags & UPDATE_DELAYED_ERASE) != 0;
 682     HDC hdc = 0;
 683     RECT dummy;
 684
 685     if (!clip_rect) clip_rect = &dummy;
 686     if (hdc_ret || (flags & UPDATE_ERASE))
 687     {
 688         UINT dcx_flags = DCX_INTERSECTRGN | DCX_USESTYLE;
 689         if (IsIconic(hwnd)) dcx_flags |= DCX_WINDOW;
 690
 691         if ((hdc = GetDCEx( hwnd, client_rgn, dcx_flags )))
 692         {
 693             INT type = GetClipBox( hdc, clip_rect );
 694
 695             if (flags & UPDATE_ERASE)
 696             {
 697                 /* don't erase if the clip box is empty */
 698                 if (type != NULLREGION)
 699                     need_erase = !SendMessageW( hwnd, WM_ERASEBKGND, (WPARAM)hdc, 0 );
 700             }
 701             if (!hdc_ret) release_dc( hwnd, hdc, TRUE );
 702         }
 703
 704         if (hdc_ret) *hdc_ret = hdc;
 705     }
 706     if (!hdc) DeleteObject( client_rgn );
 707     return need_erase;
 708 }
 709
 710
 711 /***********************************************************************
 712  *           erase_now
 713  *
 714  * Implementation of RDW_ERASENOW behavior.
 715  */
 716 void erase_now( HWND hwnd, UINT rdw_flags )
 717 {
 718     HWND child = 0;
 719     HRGN hrgn;
 720     BOOL need_erase = FALSE;
 721
 722     /* loop while we find a child to repaint */
 723     for (;;)
 724     {
 725         UINT flags = UPDATE_NONCLIENT | UPDATE_ERASE;
 726
 727         if (rdw_flags & RDW_NOCHILDREN) flags |= UPDATE_NOCHILDREN;
 728         else if (rdw_flags & RDW_ALLCHILDREN) flags |= UPDATE_ALLCHILDREN;
 729         if (need_erase) flags |= UPDATE_DELAYED_ERASE;
 730
 731         if (!(hrgn = send_ncpaint( hwnd, &child, &flags ))) break;
 732         need_erase = send_erase( child, flags, hrgn, NULL, NULL );
 733
 734         if (!flags) break;  /* nothing more to do */
 735         if ((rdw_flags & RDW_NOCHILDREN) && !need_erase) break;
 736     }
 737 }
 738
 739
 740 /***********************************************************************
 741  *           update_now
 742  *
 743  * Implementation of RDW_UPDATENOW behavior.
 744  *
 745  * FIXME: Windows uses WM_SYNCPAINT to cut down the number of intertask
 746  * SendMessage() calls. This is a comment inside DefWindowProc() source
 747  * from 16-bit SDK:
 748  *
 749  *   This message avoids lots of inter-app message traffic
 750  *   by switching to the other task and continuing the
 751  *   recursion there.
 752  *
 753  * wParam         = flags
 754  * LOWORD(lParam) = hrgnClip
 755  * HIWORD(lParam) = hwndSkip  (not used; always NULL)
 756  *
 757  */
 758 static void update_now( HWND hwnd, UINT rdw_flags )
 759 {
 760     HWND child = 0;
 761
 762     /* desktop window never gets WM_PAINT, only WM_ERASEBKGND */
 763     if (hwnd == GetDesktopWindow()) erase_now( hwnd, rdw_flags | RDW_NOCHILDREN );
 764
 765     /* loop while we find a child to repaint */
 766     for (;;)
 767     {
 768         UINT flags = UPDATE_PAINT | UPDATE_INTERNALPAINT;
 769
 770         if (rdw_flags & RDW_NOCHILDREN) flags |= UPDATE_NOCHILDREN;
 771         else if (rdw_flags & RDW_ALLCHILDREN) flags |= UPDATE_ALLCHILDREN;
 772
 773         if (!get_update_flags( hwnd, &child, &flags )) break;
 774         if (!flags) break;  /* nothing more to do */
 775
 776         SendMessageW( child, WM_PAINT, 0, 0 );
 777         if (rdw_flags & RDW_NOCHILDREN) break;
 778     }
 779 }
 780
 781
 782 /*************************************************************************
 783  *             fix_caret
 784  *
 785  * Helper for ScrollWindowEx:
 786  * If the return value is 0, no special caret handling is necessary.
 787  * Otherwise the return value is the handle of the window that owns the
 788  * caret. Its caret needs to be hidden during the scroll operation and
 789  * moved to new_caret_pos if move_caret is TRUE.
 790  */
 791 static HWND fix_caret(HWND hWnd, const RECT *scroll_rect, INT dx, INT dy,
 792                      UINT flags, LPBOOL move_caret, LPPOINT new_caret_pos)
 793 {
 794     GUITHREADINFO info;
 795     RECT rect, mapped_rcCaret;
 796     BOOL hide_caret = FALSE;
 797
 798     if (!GetGUIThreadInfo( GetCurrentThreadId(), &info )) return 0;
 799     if (!info.hwndCaret) return 0;
 800
 801     if (info.hwndCaret == hWnd)
 802     {
 803         /* Move the caret if it's (partially) in the source rectangle */
 804         if (IntersectRect(&rect, scroll_rect, &info.rcCaret))
 805         {
 806             *move_caret = TRUE;
 807             hide_caret = TRUE;
 808             new_caret_pos->x = info.rcCaret.left + dx;
 809             new_caret_pos->y = info.rcCaret.top + dy;
 810         }
 811         else
 812         {
 813             *move_caret = FALSE;
 814
 815             /* Hide the caret if it's in the destination rectangle */
 816             rect = *scroll_rect;
 817             OffsetRect(&rect, dx, dy);
 818             hide_caret = IntersectRect(&rect, &rect, &info.rcCaret);
 819         }
 820     }
 821     else
 822     {
 823         if ((flags & SW_SCROLLCHILDREN) && IsChild(hWnd, info.hwndCaret))
 824         {
 825             *move_caret = FALSE;
 826
 827             /* Hide the caret if it's in the source or in the destination
 828                rectangle */
 829             mapped_rcCaret = info.rcCaret;
 830             MapWindowPoints(info.hwndCaret, hWnd, (LPPOINT)&mapped_rcCaret, 2);
 831
 832             if (IntersectRect(&rect, scroll_rect, &mapped_rcCaret))
 833             {
 834                 hide_caret = TRUE;
 835             }
 836             else
 837             {
 838                 rect = *scroll_rect;
 839                 OffsetRect(&rect, dx, dy);
 840                 hide_caret = IntersectRect(&rect, &rect, &mapped_rcCaret);
 841             }
 842         }
 843         else
 844             return 0;
 845     }
 846
 847     if (hide_caret)
 848     {
 849         HideCaret(info.hwndCaret);
 850         return info.hwndCaret;
 851     }
 852     else
 853         return 0;
 854 }
 855
 856
 857 /***********************************************************************
 858  *              BeginPaint (USER32.@)
 859  */
 860 HDC WINAPI BeginPaint( HWND hwnd, PAINTSTRUCT *lps )
 861 {
 862     HRGN hrgn;
 863     UINT flags = UPDATE_NONCLIENT | UPDATE_ERASE | UPDATE_PAINT | UPDATE_INTERNALPAINT | UPDATE_NOCHILDREN;
 864
 865     if (!lps) return 0;
 866
 867     HideCaret( hwnd );
 868
 869     if (!(hrgn = send_ncpaint( hwnd, NULL, &flags ))) return 0;
 870
 871     lps->fErase = send_erase( hwnd, flags, hrgn, &lps->rcPaint, &lps->hdc );
 872
 873     TRACE("hdc = %p box = (%s), fErase = %d\n",
 874           lps->hdc, wine_dbgstr_rect(&lps->rcPaint), lps->fErase);
 875
 876     return lps->hdc;
 877 }
 878
 879
 880 /***********************************************************************
 881  *              EndPaint (USER32.@)
 882  */
 883 BOOL WINAPI EndPaint( HWND hwnd, const PAINTSTRUCT *lps )
 884 {
 885     if (!lps) return FALSE;
 886     release_dc( hwnd, lps->hdc, TRUE );
 887     ShowCaret( hwnd );
 888     return TRUE;
 889 }
 890
 891
 892 /***********************************************************************
 893  *              GetDCEx (USER32.@)
 894  */
 895 HDC WINAPI GetDCEx( HWND hwnd, HRGN hrgnClip, DWORD flags )
 896 {
 897     static const DWORD clip_flags = DCX_PARENTCLIP | DCX_CLIPSIBLINGS | DCX_CLIPCHILDREN | DCX_WINDOW;
 898     struct dce *dce;
 899     BOOL bUpdateVisRgn = TRUE;
 900     HWND parent;
 901     LONG window_style = GetWindowLongW( hwnd, GWL_STYLE );
 902
 903     if (!hwnd) hwnd = GetDesktopWindow();
 904     else hwnd = WIN_GetFullHandle( hwnd );
 905
 906     TRACE("hwnd %p, hrgnClip %p, flags %08x\n", hwnd, hrgnClip, flags);
 907
 908     /* fixup flags */
 909
 910     if (flags & (DCX_WINDOW | DCX_PARENTCLIP)) flags |= DCX_CACHE;
 911
 912     if (flags & DCX_USESTYLE)
 913     {
 914         flags &= ~(DCX_CLIPCHILDREN | DCX_CLIPSIBLINGS | DCX_PARENTCLIP);
 915
 916         if (window_style & WS_CLIPSIBLINGS) flags |= DCX_CLIPSIBLINGS;
 917
 918         if (!(flags & DCX_WINDOW))
 919         {
 920             if (GetClassLongW( hwnd, GCL_STYLE ) & CS_PARENTDC) flags |= DCX_PARENTCLIP;
 921
 922             if (window_style & WS_CLIPCHILDREN && !(window_style & WS_MINIMIZE))
 923                 flags |= DCX_CLIPCHILDREN;
 924         }
 925     }
 926
 927     if (flags & DCX_WINDOW) flags &= ~DCX_CLIPCHILDREN;
 928
 929     parent = GetAncestor( hwnd, GA_PARENT );
 930     if (!parent || (parent == GetDesktopWindow()))
 931         flags = (flags & ~DCX_PARENTCLIP) | DCX_CLIPSIBLINGS;
 932
 933     /* it seems parent clip is ignored when clipping siblings or children */
 934     if (flags & (DCX_CLIPSIBLINGS | DCX_CLIPCHILDREN)) flags &= ~DCX_PARENTCLIP;
 935
 936     if( flags & DCX_PARENTCLIP )
 937     {
 938         LONG parent_style = GetWindowLongW( parent, GWL_STYLE );
 939         if( (window_style & WS_VISIBLE) && (parent_style & WS_VISIBLE) )
 940         {
 941             flags &= ~DCX_CLIPCHILDREN;
 942             if (parent_style & WS_CLIPSIBLINGS) flags |= DCX_CLIPSIBLINGS;
 943         }
 944     }
 945
 946     /* find a suitable DCE */
 947
 948     if ((flags & DCX_CACHE) || !(dce = get_window_dce( hwnd )))
 949     {
 950         struct dce *dceEmpty = NULL, *dceUnused = NULL;
 951
 952         /* Strategy: First, we attempt to find a non-empty but unused DCE with
 953          * compatible flags. Next, we look for an empty entry. If the cache is
 954          * full we have to purge one of the unused entries.
 955          */
 956         USER_Lock();
 957         LIST_FOR_EACH_ENTRY( dce, &dce_list, struct dce, entry )
 958         {
 959             if ((dce->flags & DCX_CACHE) && !dce->count)
 960             {
 961                 dceUnused = dce;
 962
 963                 if (!dce->hwnd) dceEmpty = dce;
 964                 else if ((dce->hwnd == hwnd) && !((dce->flags ^ flags) & clip_flags))
 965                 {
 966                     TRACE("\tfound valid %p dce [%p], flags %08x\n",
 967                           dce, hwnd, dce->flags );
 968                     bUpdateVisRgn = FALSE;
 969                     break;
 970                 }
 971             }
 972         }
 973
 974         if (&dce->entry == &dce_list)  /* nothing found */
 975             dce = dceEmpty ? dceEmpty : dceUnused;
 976
 977         if (dce) dce->count = 1;
 978
 979         USER_Unlock();
 980
 981         /* if there's no dce empty or unused, allocate a new one */
 982         if (!dce)
 983         {
 984             if (!(dce = alloc_dce())) return 0;
 985             dce->flags = DCX_CACHE;
 986             USER_Lock();
 987             list_add_head( &dce_list, &dce->entry );
 988             USER_Unlock();
 989         }
 990     }
 991     else
 992     {
 993         flags |= DCX_NORESETATTRS;
 994         if (dce->hwnd == hwnd)
 995         {
 996             TRACE("\tskipping hVisRgn update\n");
 997             bUpdateVisRgn = FALSE; /* updated automatically, via DCHook() */
 998         }
 999         else
1000         {
1001             /* we should free dce->clip_rgn here, but Windows apparently doesn't */
1002             dce->flags &= ~(DCX_EXCLUDERGN | DCX_INTERSECTRGN);
1003             dce->clip_rgn = 0;
1004         }
1005     }
1006
1007     if (flags & (DCX_INTERSECTRGN | DCX_EXCLUDERGN))
1008     {
1009         /* if the extra clip region has changed, get rid of the old one */
1010         if (dce->clip_rgn != hrgnClip || ((flags ^ dce->flags) & (DCX_INTERSECTRGN | DCX_EXCLUDERGN)))
1011             delete_clip_rgn( dce );
1012         dce->clip_rgn = hrgnClip;
1013         if (!dce->clip_rgn) dce->clip_rgn = CreateRectRgn( 0, 0, 0, 0 );
1014         dce->flags |= flags & (DCX_INTERSECTRGN | DCX_EXCLUDERGN);
1015         bUpdateVisRgn = TRUE;
1016     }
1017
1018     dce->hwnd = hwnd;
1019     dce->flags = (dce->flags & ~clip_flags) | (flags & clip_flags);
1020
1021     if (SetHookFlags( dce->hdc, DCHF_VALIDATEVISRGN )) bUpdateVisRgn = TRUE;  /* DC was dirty */
1022
1023     if (bUpdateVisRgn) update_visible_region( dce );
1024
1025     if (!(flags & DCX_NORESETATTRS))
1026     {
1027         RestoreDC( dce->hdc, 1 );  /* initial save level is always 1 */
1028         SaveDC( dce->hdc );  /* save the state again for next time */
1029     }
1030
1031     TRACE("(%p,%p,0x%x): returning %p\n", hwnd, hrgnClip, flags, dce->hdc);
1032     return dce->hdc;
1033 }
1034
1035
1036 /***********************************************************************
1037  *              GetDC (USER32.@)
1038  *
1039  * Get a device context.
1040  *
1041  * RETURNS
1042  *      Success: Handle to the device context
1043  *      Failure: NULL.
1044  */
1045 HDC WINAPI GetDC( HWND hwnd )
1046 {
1047     if (!hwnd) return GetDCEx( 0, 0, DCX_CACHE | DCX_WINDOW );
1048     return GetDCEx( hwnd, 0, DCX_USESTYLE );
1049 }
1050
1051
1052 /***********************************************************************
1053  *              GetWindowDC (USER32.@)
1054  */
1055 HDC WINAPI GetWindowDC( HWND hwnd )
1056 {
1057     return GetDCEx( hwnd, 0, DCX_USESTYLE | DCX_WINDOW );
1058 }
1059
1060
1061 /***********************************************************************
1062  *              ReleaseDC (USER32.@)
1063  *
1064  * Release a device context.
1065  *
1066  * RETURNS
1067  *      Success: Non-zero. Resources used by hdc are released.
1068  *      Failure: 0.
1069  */
1070 INT WINAPI ReleaseDC( HWND hwnd, HDC hdc )
1071 {
1072     return release_dc( hwnd, hdc, FALSE );
1073 }
1074
1075
1076 /**********************************************************************
1077  *              WindowFromDC (USER32.@)
1078  */
1079 HWND WINAPI WindowFromDC( HDC hdc )
1080 {
1081     struct dce *dce;
1082     HWND hwnd = 0;
1083
1084     USER_Lock();
1085     dce = (struct dce *)GetDCHook( hdc, NULL );
1086     if (dce) hwnd = dce->hwnd;
1087     USER_Unlock();
1088     return hwnd;
1089 }
1090
1091
1092 /***********************************************************************
1093  *              LockWindowUpdate (USER32.@)
1094  *
1095  * Enables or disables painting in the chosen window.
1096  *
1097  * PARAMS
1098  *  hwnd [I] handle to a window.
1099  *
1100  * RETURNS
1101  *  If successful, returns nonzero value. Otherwise,
1102  *  returns 0.
1103  *
1104  * NOTES
1105  *  You can lock only one window at a time.
1106  */
1107 BOOL WINAPI LockWindowUpdate( HWND hwnd )
1108 {
1109     static HWND lockedWnd;
1110
1111     /* This function is fully implemented by the following patch:
1112      *
1113      * http://www.winehq.org/hypermail/wine-patches/2004/01/0142.html
1114      *
1115      * but in order to work properly, it needs the ability to invalidate
1116      * DCEs in other processes when the lock window is changed, which
1117      * isn't possible yet.
1118      * -mike
1119      */
1120
1121     FIXME("(%p), partial stub!\n",hwnd);
1122
1123     USER_Lock();
1124     if (lockedWnd)
1125     {
1126         if (!hwnd)
1127         {
1128             /* Unlock lockedWnd */
1129             /* FIXME: Do something */
1130         }
1131         else
1132         {
1133             /* Attempted to lock a second window */
1134             /* Return FALSE and do nothing */
1135             USER_Unlock();
1136             return FALSE;
1137         }
1138     }
1139     lockedWnd = hwnd;
1140     USER_Unlock();
1141     return TRUE;
1142 }
1143
1144
1145 /***********************************************************************
1146  *              RedrawWindow (USER32.@)
1147  */
1148 BOOL WINAPI RedrawWindow( HWND hwnd, const RECT *rect, HRGN hrgn, UINT flags )
1149 {
1150     static const RECT empty;
1151     BOOL ret;
1152
1153     if (!hwnd) hwnd = GetDesktopWindow();
1154
1155     if (TRACE_ON(win))
1156     {
1157         if (hrgn)
1158         {
1159             RECT r;
1160             GetRgnBox( hrgn, &r );
1161             TRACE( "%p region %p box %s ", hwnd, hrgn, wine_dbgstr_rect(&r) );
1162         }
1163         else if (rect)
1164             TRACE( "%p rect %s ", hwnd, wine_dbgstr_rect(rect) );
1165         else
1166             TRACE( "%p whole window ", hwnd );
1167
1168         dump_rdw_flags(flags);
1169     }
1170
1171     /* process pending expose events before painting */
1172     if (flags & RDW_UPDATENOW) USER_Driver->pMsgWaitForMultipleObjectsEx( 0, NULL, 0, QS_PAINT, 0 );
1173
1174     if (rect && !hrgn)
1175     {
1176         if (IsRectEmpty( rect )) rect = &empty;
1177         ret = redraw_window_rects( hwnd, flags, rect, 1 );
1178     }
1179     else if (!hrgn)
1180     {
1181         ret = redraw_window_rects( hwnd, flags, NULL, 0 );
1182     }
1183     else  /* need to build a list of the region rectangles */
1184     {
1185         DWORD size;
1186         RGNDATA *data = NULL;
1187
1188         if (!(size = GetRegionData( hrgn, 0, NULL ))) return FALSE;
1189         if (!(data = HeapAlloc( GetProcessHeap(), 0, size ))) return FALSE;
1190         GetRegionData( hrgn, size, data );
1191         if (!data->rdh.nCount)  /* empty region -> use a single all-zero rectangle */
1192             ret = redraw_window_rects( hwnd, flags, &empty, 1 );
1193         else
1194             ret = redraw_window_rects( hwnd, flags, (const RECT *)data->Buffer, data->rdh.nCount );
1195         HeapFree( GetProcessHeap(), 0, data );
1196     }
1197
1198     if (flags & RDW_UPDATENOW) update_now( hwnd, flags );
1199     else if (flags & RDW_ERASENOW) erase_now( hwnd, flags );
1200
1201     return ret;
1202 }
1203
1204
1205 /***********************************************************************
1206  *              UpdateWindow (USER32.@)
1207  */
1208 BOOL WINAPI UpdateWindow( HWND hwnd )
1209 {
1210     return RedrawWindow( hwnd, NULL, 0, RDW_UPDATENOW | RDW_ALLCHILDREN );
1211 }
1212
1213
1214 /***********************************************************************
1215  *              InvalidateRgn (USER32.@)
1216  */
1217 BOOL WINAPI InvalidateRgn( HWND hwnd, HRGN hrgn, BOOL erase )
1218 {
1219     if (!hwnd)
1220     {
1221         SetLastError( ERROR_INVALID_WINDOW_HANDLE );
1222         return FALSE;
1223     }
1224
1225     return RedrawWindow(hwnd, NULL, hrgn, RDW_INVALIDATE | (erase ? RDW_ERASE : 0) );
1226 }
1227
1228
1229 /***********************************************************************
1230  *              InvalidateRect (USER32.@)
1231  *
1232  * MSDN: if hwnd parameter is NULL, InvalidateRect invalidates and redraws
1233  * all windows and sends WM_ERASEBKGND and WM_NCPAINT.
1234  */
1235 BOOL WINAPI InvalidateRect( HWND hwnd, const RECT *rect, BOOL erase )
1236 {
1237     UINT flags = RDW_INVALIDATE | (erase ? RDW_ERASE : 0);
1238
1239     if (!hwnd)
1240     {
1241         flags = RDW_ALLCHILDREN | RDW_INVALIDATE | RDW_FRAME | RDW_ERASE | RDW_ERASENOW;
1242         rect = NULL;
1243     }
1244
1245     return RedrawWindow( hwnd, rect, 0, flags );
1246 }
1247
1248
1249 /***********************************************************************
1250  *              ValidateRgn (USER32.@)
1251  */
1252 BOOL WINAPI ValidateRgn( HWND hwnd, HRGN hrgn )
1253 {
1254     if (!hwnd)
1255     {
1256         SetLastError( ERROR_INVALID_WINDOW_HANDLE );
1257         return FALSE;
1258     }
1259
1260     return RedrawWindow( hwnd, NULL, hrgn, RDW_VALIDATE );
1261 }
1262
1263
1264 /***********************************************************************
1265  *              ValidateRect (USER32.@)
1266  *
1267  * MSDN: if hwnd parameter is NULL, ValidateRect invalidates and redraws
1268  * all windows and sends WM_ERASEBKGND and WM_NCPAINT.
1269  */
1270 BOOL WINAPI ValidateRect( HWND hwnd, const RECT *rect )
1271 {
1272     UINT flags = RDW_VALIDATE;
1273
1274     if (!hwnd)
1275     {
1276         flags = RDW_ALLCHILDREN | RDW_INVALIDATE | RDW_FRAME | RDW_ERASE | RDW_ERASENOW;
1277         rect = NULL;
1278     }
1279
1280     return RedrawWindow( hwnd, rect, 0, flags );
1281 }
1282
1283
1284 /***********************************************************************
1285  *              GetUpdateRgn (USER32.@)
1286  */
1287 INT WINAPI GetUpdateRgn( HWND hwnd, HRGN hrgn, BOOL erase )
1288 {
1289     INT retval = ERROR;
1290     UINT flags = UPDATE_NOCHILDREN;
1291     HRGN update_rgn;
1292
1293     if (erase) flags |= UPDATE_NONCLIENT | UPDATE_ERASE;
1294
1295     if ((update_rgn = send_ncpaint( hwnd, NULL, &flags )))
1296     {
1297         POINT offset;
1298
1299         retval = CombineRgn( hrgn, update_rgn, 0, RGN_COPY );
1300         if (send_erase( hwnd, flags, update_rgn, NULL, NULL ))
1301         {
1302             flags = UPDATE_DELAYED_ERASE;
1303             get_update_flags( hwnd, NULL, &flags );
1304         }
1305         /* map region to client coordinates */
1306         offset.x = offset.y = 0;
1307         ScreenToClient( hwnd, &offset );
1308         OffsetRgn( hrgn, offset.x, offset.y );
1309     }
1310     return retval;
1311 }
1312
1313
1314 /***********************************************************************
1315  *              GetUpdateRect (USER32.@)
1316  */
1317 BOOL WINAPI GetUpdateRect( HWND hwnd, LPRECT rect, BOOL erase )
1318 {
1319     UINT flags = UPDATE_NOCHILDREN;
1320     HRGN update_rgn;
1321     BOOL need_erase;
1322
1323     if (erase) flags |= UPDATE_NONCLIENT | UPDATE_ERASE;
1324
1325     if (!(update_rgn = send_ncpaint( hwnd, NULL, &flags ))) return FALSE;
1326
1327     if (rect)
1328     {
1329         if (GetRgnBox( update_rgn, rect ) != NULLREGION)
1330         {
1331             HDC hdc = GetDCEx( hwnd, 0, DCX_USESTYLE );
1332             MapWindowPoints( 0, hwnd, (LPPOINT)rect, 2 );
1333             DPtoLP( hdc, (LPPOINT)rect, 2 );
1334             ReleaseDC( hwnd, hdc );
1335         }
1336     }
1337     need_erase = send_erase( hwnd, flags, update_rgn, NULL, NULL );
1338
1339     /* check if we still have an update region */
1340     flags = UPDATE_PAINT | UPDATE_NOCHILDREN;
1341     if (need_erase) flags |= UPDATE_DELAYED_ERASE;
1342     return (get_update_flags( hwnd, NULL, &flags ) && (flags & UPDATE_PAINT));
1343 }
1344
1345
1346 /***********************************************************************
1347  *              ExcludeUpdateRgn (USER32.@)
1348  */
1349 INT WINAPI ExcludeUpdateRgn( HDC hdc, HWND hwnd )
1350 {
1351     HRGN update_rgn = CreateRectRgn( 0, 0, 0, 0 );
1352     INT ret = GetUpdateRgn( hwnd, update_rgn, FALSE );
1353
1354     if (ret != ERROR)
1355     {
1356         POINT pt;
1357
1358         GetDCOrgEx( hdc, &pt );
1359         MapWindowPoints( 0, hwnd, &pt, 1 );
1360         OffsetRgn( update_rgn, -pt.x, -pt.y );
1361         ret = ExtSelectClipRgn( hdc, update_rgn, RGN_DIFF );
1362         DeleteObject( update_rgn );
1363     }
1364     return ret;
1365 }
1366
1367
1368 /*************************************************************************
1369  *              ScrollWindowEx (USER32.@)
1370  *
1371  * Note: contrary to what the doc says, pixels that are scrolled from the
1372  *      outside of clipRect to the inside are NOT painted.
1373  *
1374  */
1375 INT WINAPI ScrollWindowEx( HWND hwnd, INT dx, INT dy,
1376                            const RECT *rect, const RECT *clipRect,
1377                            HRGN hrgnUpdate, LPRECT rcUpdate,
1378                            UINT flags )
1379 {
1380     INT   retVal = NULLREGION;
1381     BOOL  bOwnRgn = TRUE;
1382     BOOL  bUpdate = (rcUpdate || hrgnUpdate || flags & (SW_INVALIDATE | SW_ERASE));
1383     int rdw_flags;
1384     HRGN  hrgnTemp;
1385     HRGN  hrgnWinupd = 0;
1386     HDC   hDC;
1387     RECT  rc, cliprc;
1388     HWND hwndCaret = NULL;
1389     BOOL moveCaret = FALSE;
1390     POINT newCaretPos;
1391
1392     TRACE( "%p, %d,%d hrgnUpdate=%p rcUpdate = %p %s %04x\n",
1393            hwnd, dx, dy, hrgnUpdate, rcUpdate, wine_dbgstr_rect(rect), flags );
1394     TRACE( "clipRect = %s\n", wine_dbgstr_rect(clipRect));
1395     if( flags & ~( SW_SCROLLCHILDREN | SW_INVALIDATE | SW_ERASE))
1396         FIXME("some flags (%04x) are unhandled\n", flags);
1397
1398     rdw_flags = (flags & SW_ERASE) && (flags & SW_INVALIDATE) ?
1399                                 RDW_INVALIDATE | RDW_ERASE  : RDW_INVALIDATE ;
1400
1401     if (!WIN_IsWindowDrawable( hwnd, TRUE )) return ERROR;
1402     hwnd = WIN_GetFullHandle( hwnd );
1403
1404     GetClientRect(hwnd, &rc);
1405     if (rect) IntersectRect(&rc, &rc, rect);
1406
1407     if (clipRect) IntersectRect(&cliprc,&rc,clipRect);
1408     else cliprc = rc;
1409
1410     if( hrgnUpdate ) bOwnRgn = FALSE;
1411     else if( bUpdate ) hrgnUpdate = CreateRectRgn( 0, 0, 0, 0 );
1412
1413     newCaretPos.x = newCaretPos.y = 0;
1414
1415     if( !IsRectEmpty(&cliprc) && (dx || dy)) {
1416         DWORD dcxflags = DCX_CACHE;
1417         DWORD style = GetWindowLongW( hwnd, GWL_STYLE );
1418
1419         hwndCaret = fix_caret(hwnd, &rc, dx, dy, flags, &moveCaret, &newCaretPos);
1420
1421         if( style & WS_CLIPSIBLINGS) dcxflags |= DCX_CLIPSIBLINGS;
1422         if( GetClassLongW( hwnd, GCL_STYLE ) & CS_PARENTDC)
1423             dcxflags |= DCX_PARENTCLIP;
1424         if( !(flags & SW_SCROLLCHILDREN) && (style & WS_CLIPCHILDREN))
1425             dcxflags |= DCX_CLIPCHILDREN;
1426         hDC = GetDCEx( hwnd, 0, dcxflags);
1427         if (hDC)
1428         {
1429             ScrollDC( hDC, dx, dy, &rc, &cliprc, hrgnUpdate, rcUpdate );
1430
1431             ReleaseDC( hwnd, hDC );
1432
1433             if (!bUpdate)
1434                 RedrawWindow( hwnd, NULL, hrgnUpdate, rdw_flags);
1435         }
1436
1437         /* If the windows has an update region, this must be
1438          * scrolled as well. Keep a copy in hrgnWinupd
1439          * to be added to hrngUpdate at the end. */
1440         hrgnTemp = CreateRectRgn( 0, 0, 0, 0 );
1441         retVal = GetUpdateRgn( hwnd, hrgnTemp, FALSE );
1442         if (retVal != NULLREGION)
1443         {
1444             HRGN hrgnClip = CreateRectRgnIndirect(&cliprc);
1445             if( !bOwnRgn) {
1446                 hrgnWinupd = CreateRectRgn( 0, 0, 0, 0);
1447                 CombineRgn( hrgnWinupd, hrgnTemp, 0, RGN_COPY);
1448             }
1449             OffsetRgn( hrgnTemp, dx, dy );
1450             CombineRgn( hrgnTemp, hrgnTemp, hrgnClip, RGN_AND );
1451             if( !bOwnRgn)
1452                 CombineRgn( hrgnWinupd, hrgnWinupd, hrgnTemp, RGN_OR );
1453             RedrawWindow( hwnd, NULL, hrgnTemp, rdw_flags);
1454
1455            /* Catch the case where the scrolling amount exceeds the size of the
1456             * original window. This generated a second update area that is the
1457             * location where the original scrolled content would end up.
1458             * This second region is not returned by the ScrollDC and sets
1459             * ScrollWindowEx apart from just a ScrollDC.
1460             *
1461             * This has been verified with testing on windows.
1462             */
1463             if (abs(dx) > abs(rc.right - rc.left) ||
1464                 abs(dy) > abs(rc.bottom - rc.top))
1465             {
1466                 SetRectRgn( hrgnTemp, rc.left + dx, rc.top + dy, rc.right+dx, rc.bottom + dy);
1467                 CombineRgn( hrgnTemp, hrgnTemp, hrgnClip, RGN_AND );
1468                 CombineRgn( hrgnUpdate, hrgnUpdate, hrgnTemp, RGN_OR );
1469
1470                 if( !bOwnRgn)
1471                     CombineRgn( hrgnWinupd, hrgnWinupd, hrgnTemp, RGN_OR );
1472             }
1473             DeleteObject( hrgnClip );
1474         }
1475         DeleteObject( hrgnTemp );
1476     } else {
1477         /* nothing was scrolled */
1478         if( !bOwnRgn)
1479             SetRectRgn( hrgnUpdate, 0, 0, 0, 0 );
1480         SetRectEmpty( rcUpdate);
1481     }
1482
1483     if( flags & SW_SCROLLCHILDREN )
1484     {
1485         HWND *list = WIN_ListChildren( hwnd );
1486         if (list)
1487         {
1488             int i;
1489             RECT r, dummy;
1490             for (i = 0; list[i]; i++)
1491             {
1492                 GetWindowRect( list[i], &r );
1493                 MapWindowPoints( 0, hwnd, (POINT *)&r, 2 );
1494                 if (!rect || IntersectRect(&dummy, &r, rect))
1495                     SetWindowPos( list[i], 0, r.left + dx, r.top  + dy, 0, 0,
1496                                   SWP_NOZORDER | SWP_NOSIZE | SWP_NOACTIVATE |
1497                                   SWP_NOREDRAW | SWP_DEFERERASE );
1498             }
1499             HeapFree( GetProcessHeap(), 0, list );
1500         }
1501     }
1502
1503     if( flags & (SW_INVALIDATE | SW_ERASE) )
1504         RedrawWindow( hwnd, NULL, hrgnUpdate, rdw_flags |
1505                       ((flags & SW_SCROLLCHILDREN) ? RDW_ALLCHILDREN : 0 ) );
1506
1507     if( hrgnWinupd) {
1508         CombineRgn( hrgnUpdate, hrgnUpdate, hrgnWinupd, RGN_OR);
1509         DeleteObject( hrgnWinupd);
1510     }
1511
1512     if( hwndCaret ) {
1513         if ( moveCaret ) SetCaretPos( newCaretPos.x, newCaretPos.y );
1514         ShowCaret(hwndCaret);
1515     }
1516
1517     if( bOwnRgn && hrgnUpdate ) DeleteObject( hrgnUpdate );
1518
1519     return retVal;
1520 }
1521
1522
1523 /*************************************************************************
1524  *              ScrollWindow (USER32.@)
1525  *
1526  */
1527 BOOL WINAPI ScrollWindow( HWND hwnd, INT dx, INT dy,
1528                           const RECT *rect, const RECT *clipRect )
1529 {
1530     return (ERROR != ScrollWindowEx( hwnd, dx, dy, rect, clipRect, 0, NULL,
1531                                      (rect ? 0 : SW_SCROLLCHILDREN) |
1532                                      SW_INVALIDATE | SW_ERASE ));
1533 }
1534
1535
1536 /*************************************************************************
1537  *              ScrollDC (USER32.@)
1538  *
1539  * dx, dy, lprcScroll and lprcClip are all in logical coordinates (msdn is
1540  * wrong) hrgnUpdate is returned in device coordinates with rcUpdate in
1541  * logical coordinates.
1542  */
1543 BOOL WINAPI ScrollDC( HDC hdc, INT dx, INT dy, const RECT *lprcScroll,
1544                       const RECT *lprcClip, HRGN hrgnUpdate, LPRECT lprcUpdate )
1545
1546 {
1547     return USER_Driver->pScrollDC( hdc, dx, dy, lprcScroll, lprcClip, hrgnUpdate, lprcUpdate );
1548 }