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 (hwnd == GetDesktopWindow()) return whole_rgn;
 627
 628     if (whole_rgn)
 629     {
 630         RECT client, update;
 631         INT type;
 632
 633         /* check if update rgn overlaps with nonclient area */
 634         type = GetRgnBox( whole_rgn, &update );
 635         GetClientRect( hwnd, &client );
 636         MapWindowPoints( hwnd, 0, (POINT *)&client, 2 );
 637
 638         if ((*flags & UPDATE_NONCLIENT) ||
 639             update.left < client.left || update.top < client.top ||
 640             update.right > client.right || update.bottom > client.bottom)
 641         {
 642             client_rgn = CreateRectRgnIndirect( &client );
 643             CombineRgn( client_rgn, client_rgn, whole_rgn, RGN_AND );
 644
 645             /* check if update rgn contains complete nonclient area */
 646             if (type == SIMPLEREGION)
 647             {
 648                 RECT window;
 649                 GetWindowRect( hwnd, &window );
 650                 if (EqualRect( &window, &update ))
 651                 {
 652                     DeleteObject( whole_rgn );
 653                     whole_rgn = (HRGN)1;
 654                 }
 655             }
 656         }
 657         else
 658         {
 659             client_rgn = whole_rgn;
 660             whole_rgn = 0;
 661         }
 662
 663         if (whole_rgn) /* NOTE: WM_NCPAINT allows wParam to be 1 */
 664         {
 665             if (*flags & UPDATE_NONCLIENT) SendMessageW( hwnd, WM_NCPAINT, (WPARAM)whole_rgn, 0 );
 666             if (whole_rgn > (HRGN)1) DeleteObject( whole_rgn );
 667         }
 668     }
 669     return client_rgn;
 670 }
 671
 672
 673 /***********************************************************************
 674  *           send_erase
 675  *
 676  * Send a WM_ERASEBKGND message if needed, and optionally return the DC for painting.
 677  * If a DC is requested, the region is selected into it. In all cases the region is deleted.
 678  * Helper for erase_now and BeginPaint.
 679  */
 680 static BOOL send_erase( HWND hwnd, UINT flags, HRGN client_rgn,
 681                         RECT *clip_rect, HDC *hdc_ret )
 682 {
 683     BOOL need_erase = (flags & UPDATE_DELAYED_ERASE) != 0;
 684     HDC hdc = 0;
 685     RECT dummy;
 686
 687     if (!clip_rect) clip_rect = &dummy;
 688     if (hdc_ret || (flags & UPDATE_ERASE))
 689     {
 690         UINT dcx_flags = DCX_INTERSECTRGN | DCX_USESTYLE;
 691         if (IsIconic(hwnd)) dcx_flags |= DCX_WINDOW;
 692
 693         if ((hdc = GetDCEx( hwnd, client_rgn, dcx_flags )))
 694         {
 695             INT type = GetClipBox( hdc, clip_rect );
 696
 697             if (flags & UPDATE_ERASE)
 698             {
 699                 /* don't erase if the clip box is empty */
 700                 if (type != NULLREGION)
 701                     need_erase = !SendMessageW( hwnd, WM_ERASEBKGND, (WPARAM)hdc, 0 );
 702             }
 703             if (!hdc_ret) release_dc( hwnd, hdc, TRUE );
 704         }
 705
 706         if (hdc_ret) *hdc_ret = hdc;
 707     }
 708     if (!hdc) DeleteObject( client_rgn );
 709     return need_erase;
 710 }
 711
 712
 713 /***********************************************************************
 714  *           erase_now
 715  *
 716  * Implementation of RDW_ERASENOW behavior.
 717  */
 718 void erase_now( HWND hwnd, UINT rdw_flags )
 719 {
 720     HWND child = 0;
 721     HRGN hrgn;
 722     BOOL need_erase = FALSE;
 723
 724     /* loop while we find a child to repaint */
 725     for (;;)
 726     {
 727         UINT flags = UPDATE_NONCLIENT | UPDATE_ERASE;
 728
 729         if (rdw_flags & RDW_NOCHILDREN) flags |= UPDATE_NOCHILDREN;
 730         else if (rdw_flags & RDW_ALLCHILDREN) flags |= UPDATE_ALLCHILDREN;
 731         if (need_erase) flags |= UPDATE_DELAYED_ERASE;
 732
 733         if (!(hrgn = send_ncpaint( hwnd, &child, &flags ))) break;
 734         need_erase = send_erase( child, flags, hrgn, NULL, NULL );
 735
 736         if (!flags) break;  /* nothing more to do */
 737         if ((rdw_flags & RDW_NOCHILDREN) && !need_erase) break;
 738     }
 739 }
 740
 741
 742 /***********************************************************************
 743  *           update_now
 744  *
 745  * Implementation of RDW_UPDATENOW behavior.
 746  *
 747  * FIXME: Windows uses WM_SYNCPAINT to cut down the number of intertask
 748  * SendMessage() calls. This is a comment inside DefWindowProc() source
 749  * from 16-bit SDK:
 750  *
 751  *   This message avoids lots of inter-app message traffic
 752  *   by switching to the other task and continuing the
 753  *   recursion there.
 754  *
 755  * wParam         = flags
 756  * LOWORD(lParam) = hrgnClip
 757  * HIWORD(lParam) = hwndSkip  (not used; always NULL)
 758  *
 759  */
 760 static void update_now( HWND hwnd, UINT rdw_flags )
 761 {
 762     HWND child = 0;
 763
 764     /* desktop window never gets WM_PAINT, only WM_ERASEBKGND */
 765     if (hwnd == GetDesktopWindow()) erase_now( hwnd, rdw_flags | RDW_NOCHILDREN );
 766
 767     /* loop while we find a child to repaint */
 768     for (;;)
 769     {
 770         UINT flags = UPDATE_PAINT | UPDATE_INTERNALPAINT;
 771
 772         if (rdw_flags & RDW_NOCHILDREN) flags |= UPDATE_NOCHILDREN;
 773         else if (rdw_flags & RDW_ALLCHILDREN) flags |= UPDATE_ALLCHILDREN;
 774
 775         if (!get_update_flags( hwnd, &child, &flags )) break;
 776         if (!flags) break;  /* nothing more to do */
 777
 778         SendMessageW( child, WM_PAINT, 0, 0 );
 779         if (rdw_flags & RDW_NOCHILDREN) break;
 780     }
 781 }
 782
 783
 784 /*************************************************************************
 785  *             fix_caret
 786  *
 787  * Helper for ScrollWindowEx:
 788  * If the return value is 0, no special caret handling is necessary.
 789  * Otherwise the return value is the handle of the window that owns the
 790  * caret. Its caret needs to be hidden during the scroll operation and
 791  * moved to new_caret_pos if move_caret is TRUE.
 792  */
 793 static HWND fix_caret(HWND hWnd, const RECT *scroll_rect, INT dx, INT dy,
 794                      UINT flags, LPBOOL move_caret, LPPOINT new_caret_pos)
 795 {
 796     GUITHREADINFO info;
 797     RECT rect, mapped_rcCaret;
 798     BOOL hide_caret = FALSE;
 799
 800     if (!GetGUIThreadInfo( GetCurrentThreadId(), &info )) return 0;
 801     if (!info.hwndCaret) return 0;
 802
 803     if (info.hwndCaret == hWnd)
 804     {
 805         /* Move the caret if it's (partially) in the source rectangle */
 806         if (IntersectRect(&rect, scroll_rect, &info.rcCaret))
 807         {
 808             *move_caret = TRUE;
 809             hide_caret = TRUE;
 810             new_caret_pos->x = info.rcCaret.left + dx;
 811             new_caret_pos->y = info.rcCaret.top + dy;
 812         }
 813         else
 814         {
 815             *move_caret = FALSE;
 816
 817             /* Hide the caret if it's in the destination rectangle */
 818             rect = *scroll_rect;
 819             OffsetRect(&rect, dx, dy);
 820             hide_caret = IntersectRect(&rect, &rect, &info.rcCaret);
 821         }
 822     }
 823     else
 824     {
 825         if ((flags & SW_SCROLLCHILDREN) && IsChild(hWnd, info.hwndCaret))
 826         {
 827             *move_caret = FALSE;
 828
 829             /* Hide the caret if it's in the source or in the destination
 830                rectangle */
 831             mapped_rcCaret = info.rcCaret;
 832             MapWindowPoints(info.hwndCaret, hWnd, (LPPOINT)&mapped_rcCaret, 2);
 833
 834             if (IntersectRect(&rect, scroll_rect, &mapped_rcCaret))
 835             {
 836                 hide_caret = TRUE;
 837             }
 838             else
 839             {
 840                 rect = *scroll_rect;
 841                 OffsetRect(&rect, dx, dy);
 842                 hide_caret = IntersectRect(&rect, &rect, &mapped_rcCaret);
 843             }
 844         }
 845         else
 846             return 0;
 847     }
 848
 849     if (hide_caret)
 850     {
 851         HideCaret(info.hwndCaret);
 852         return info.hwndCaret;
 853     }
 854     else
 855         return 0;
 856 }
 857
 858
 859 /***********************************************************************
 860  *              BeginPaint (USER32.@)
 861  */
 862 HDC WINAPI BeginPaint( HWND hwnd, PAINTSTRUCT *lps )
 863 {
 864     HRGN hrgn;
 865     UINT flags = UPDATE_NONCLIENT | UPDATE_ERASE | UPDATE_PAINT | UPDATE_INTERNALPAINT | UPDATE_NOCHILDREN;
 866
 867     if (!lps) return 0;
 868
 869     HideCaret( hwnd );
 870
 871     if (!(hrgn = send_ncpaint( hwnd, NULL, &flags ))) return 0;
 872
 873     lps->fErase = send_erase( hwnd, flags, hrgn, &lps->rcPaint, &lps->hdc );
 874
 875     TRACE("hdc = %p box = (%s), fErase = %d\n",
 876           lps->hdc, wine_dbgstr_rect(&lps->rcPaint), lps->fErase);
 877
 878     return lps->hdc;
 879 }
 880
 881
 882 /***********************************************************************
 883  *              EndPaint (USER32.@)
 884  */
 885 BOOL WINAPI EndPaint( HWND hwnd, const PAINTSTRUCT *lps )
 886 {
 887     if (!lps) return FALSE;
 888     release_dc( hwnd, lps->hdc, TRUE );
 889     ShowCaret( hwnd );
 890     return TRUE;
 891 }
 892
 893
 894 /***********************************************************************
 895  *              GetDCEx (USER32.@)
 896  */
 897 HDC WINAPI GetDCEx( HWND hwnd, HRGN hrgnClip, DWORD flags )
 898 {
 899     static const DWORD clip_flags = DCX_PARENTCLIP | DCX_CLIPSIBLINGS | DCX_CLIPCHILDREN | DCX_WINDOW;
 900     struct dce *dce;
 901     BOOL bUpdateVisRgn = TRUE;
 902     HWND parent;
 903     LONG window_style = GetWindowLongW( hwnd, GWL_STYLE );
 904
 905     if (!hwnd) hwnd = GetDesktopWindow();
 906     else hwnd = WIN_GetFullHandle( hwnd );
 907
 908     TRACE("hwnd %p, hrgnClip %p, flags %08x\n", hwnd, hrgnClip, flags);
 909
 910     /* fixup flags */
 911
 912     if (flags & (DCX_WINDOW | DCX_PARENTCLIP)) flags |= DCX_CACHE;
 913
 914     if (flags & DCX_USESTYLE)
 915     {
 916         flags &= ~(DCX_CLIPCHILDREN | DCX_CLIPSIBLINGS | DCX_PARENTCLIP);
 917
 918         if (window_style & WS_CLIPSIBLINGS) flags |= DCX_CLIPSIBLINGS;
 919
 920         if (!(flags & DCX_WINDOW))
 921         {
 922             if (GetClassLongW( hwnd, GCL_STYLE ) & CS_PARENTDC) flags |= DCX_PARENTCLIP;
 923
 924             if (window_style & WS_CLIPCHILDREN && !(window_style & WS_MINIMIZE))
 925                 flags |= DCX_CLIPCHILDREN;
 926         }
 927     }
 928
 929     if (flags & DCX_WINDOW) flags &= ~DCX_CLIPCHILDREN;
 930
 931     parent = GetAncestor( hwnd, GA_PARENT );
 932     if (!parent || (parent == GetDesktopWindow()))
 933         flags = (flags & ~DCX_PARENTCLIP) | DCX_CLIPSIBLINGS;
 934
 935     /* it seems parent clip is ignored when clipping siblings or children */
 936     if (flags & (DCX_CLIPSIBLINGS | DCX_CLIPCHILDREN)) flags &= ~DCX_PARENTCLIP;
 937
 938     if( flags & DCX_PARENTCLIP )
 939     {
 940         LONG parent_style = GetWindowLongW( parent, GWL_STYLE );
 941         if( (window_style & WS_VISIBLE) && (parent_style & WS_VISIBLE) )
 942         {
 943             flags &= ~DCX_CLIPCHILDREN;
 944             if (parent_style & WS_CLIPSIBLINGS) flags |= DCX_CLIPSIBLINGS;
 945         }
 946     }
 947
 948     /* find a suitable DCE */
 949
 950     if ((flags & DCX_CACHE) || !(dce = get_window_dce( hwnd )))
 951     {
 952         struct dce *dceEmpty = NULL, *dceUnused = NULL;
 953
 954         /* Strategy: First, we attempt to find a non-empty but unused DCE with
 955          * compatible flags. Next, we look for an empty entry. If the cache is
 956          * full we have to purge one of the unused entries.
 957          */
 958         USER_Lock();
 959         LIST_FOR_EACH_ENTRY( dce, &dce_list, struct dce, entry )
 960         {
 961             if ((dce->flags & DCX_CACHE) && !dce->count)
 962             {
 963                 dceUnused = dce;
 964
 965                 if (!dce->hwnd) dceEmpty = dce;
 966                 else if ((dce->hwnd == hwnd) && !((dce->flags ^ flags) & clip_flags))
 967                 {
 968                     TRACE("\tfound valid %p dce [%p], flags %08x\n",
 969                           dce, hwnd, dce->flags );
 970                     bUpdateVisRgn = FALSE;
 971                     break;
 972                 }
 973             }
 974         }
 975
 976         if (&dce->entry == &dce_list)  /* nothing found */
 977             dce = dceEmpty ? dceEmpty : dceUnused;
 978
 979         if (dce) dce->count = 1;
 980
 981         USER_Unlock();
 982
 983         /* if there's no dce empty or unused, allocate a new one */
 984         if (!dce)
 985         {
 986             if (!(dce = alloc_dce())) return 0;
 987             dce->flags = DCX_CACHE;
 988             USER_Lock();
 989             list_add_head( &dce_list, &dce->entry );
 990             USER_Unlock();
 991         }
 992     }
 993     else
 994     {
 995         flags |= DCX_NORESETATTRS;
 996         if (dce->hwnd == hwnd)
 997         {
 998             TRACE("\tskipping hVisRgn update\n");
 999             bUpdateVisRgn = FALSE; /* updated automatically, via DCHook() */
1000         }
1001         else
1002         {
1003             /* we should free dce->clip_rgn here, but Windows apparently doesn't */
1004             dce->flags &= ~(DCX_EXCLUDERGN | DCX_INTERSECTRGN);
1005             dce->clip_rgn = 0;
1006         }
1007     }
1008
1009     if (flags & (DCX_INTERSECTRGN | DCX_EXCLUDERGN))
1010     {
1011         /* if the extra clip region has changed, get rid of the old one */
1012         if (dce->clip_rgn != hrgnClip || ((flags ^ dce->flags) & (DCX_INTERSECTRGN | DCX_EXCLUDERGN)))
1013             delete_clip_rgn( dce );
1014         dce->clip_rgn = hrgnClip;
1015         if (!dce->clip_rgn) dce->clip_rgn = CreateRectRgn( 0, 0, 0, 0 );
1016         dce->flags |= flags & (DCX_INTERSECTRGN | DCX_EXCLUDERGN);
1017         bUpdateVisRgn = TRUE;
1018     }
1019
1020     dce->hwnd = hwnd;
1021     dce->flags = (dce->flags & ~clip_flags) | (flags & clip_flags);
1022
1023     if (SetHookFlags( dce->hdc, DCHF_VALIDATEVISRGN )) bUpdateVisRgn = TRUE;  /* DC was dirty */
1024
1025     if (bUpdateVisRgn) update_visible_region( dce );
1026
1027     if (!(flags & DCX_NORESETATTRS))
1028     {
1029         RestoreDC( dce->hdc, 1 );  /* initial save level is always 1 */
1030         SaveDC( dce->hdc );  /* save the state again for next time */
1031     }
1032
1033     TRACE("(%p,%p,0x%x): returning %p\n", hwnd, hrgnClip, flags, dce->hdc);
1034     return dce->hdc;
1035 }
1036
1037
1038 /***********************************************************************
1039  *              GetDC (USER32.@)
1040  *
1041  * Get a device context.
1042  *
1043  * RETURNS
1044  *      Success: Handle to the device context
1045  *      Failure: NULL.
1046  */
1047 HDC WINAPI GetDC( HWND hwnd )
1048 {
1049     if (!hwnd) return GetDCEx( 0, 0, DCX_CACHE | DCX_WINDOW );
1050     return GetDCEx( hwnd, 0, DCX_USESTYLE );
1051 }
1052
1053
1054 /***********************************************************************
1055  *              GetWindowDC (USER32.@)
1056  */
1057 HDC WINAPI GetWindowDC( HWND hwnd )
1058 {
1059     return GetDCEx( hwnd, 0, DCX_USESTYLE | DCX_WINDOW );
1060 }
1061
1062
1063 /***********************************************************************
1064  *              ReleaseDC (USER32.@)
1065  *
1066  * Release a device context.
1067  *
1068  * RETURNS
1069  *      Success: Non-zero. Resources used by hdc are released.
1070  *      Failure: 0.
1071  */
1072 INT WINAPI ReleaseDC( HWND hwnd, HDC hdc )
1073 {
1074     return release_dc( hwnd, hdc, FALSE );
1075 }
1076
1077
1078 /**********************************************************************
1079  *              WindowFromDC (USER32.@)
1080  */
1081 HWND WINAPI WindowFromDC( HDC hdc )
1082 {
1083     struct dce *dce;
1084     HWND hwnd = 0;
1085
1086     USER_Lock();
1087     dce = (struct dce *)GetDCHook( hdc, NULL );
1088     if (dce) hwnd = dce->hwnd;
1089     USER_Unlock();
1090     return hwnd;
1091 }
1092
1093
1094 /***********************************************************************
1095  *              LockWindowUpdate (USER32.@)
1096  *
1097  * Enables or disables painting in the chosen window.
1098  *
1099  * PARAMS
1100  *  hwnd [I] handle to a window.
1101  *
1102  * RETURNS
1103  *  If successful, returns nonzero value. Otherwise,
1104  *  returns 0.
1105  *
1106  * NOTES
1107  *  You can lock only one window at a time.
1108  */
1109 BOOL WINAPI LockWindowUpdate( HWND hwnd )
1110 {
1111     static HWND lockedWnd;
1112
1113     /* This function is fully implemented by the following patch:
1114      *
1115      * http://www.winehq.org/hypermail/wine-patches/2004/01/0142.html
1116      *
1117      * but in order to work properly, it needs the ability to invalidate
1118      * DCEs in other processes when the lock window is changed, which
1119      * isn't possible yet.
1120      * -mike
1121      */
1122
1123     FIXME("(%p), partial stub!\n",hwnd);
1124
1125     USER_Lock();
1126     if (lockedWnd)
1127     {
1128         if (!hwnd)
1129         {
1130             /* Unlock lockedWnd */
1131             /* FIXME: Do something */
1132         }
1133         else
1134         {
1135             /* Attempted to lock a second window */
1136             /* Return FALSE and do nothing */
1137             USER_Unlock();
1138             return FALSE;
1139         }
1140     }
1141     lockedWnd = hwnd;
1142     USER_Unlock();
1143     return TRUE;
1144 }
1145
1146
1147 /***********************************************************************
1148  *              RedrawWindow (USER32.@)
1149  */
1150 BOOL WINAPI RedrawWindow( HWND hwnd, const RECT *rect, HRGN hrgn, UINT flags )
1151 {
1152     static const RECT empty;
1153     BOOL ret;
1154
1155     if (!hwnd) hwnd = GetDesktopWindow();
1156
1157     if (TRACE_ON(win))
1158     {
1159         if (hrgn)
1160         {
1161             RECT r;
1162             GetRgnBox( hrgn, &r );
1163             TRACE( "%p region %p box %s ", hwnd, hrgn, wine_dbgstr_rect(&r) );
1164         }
1165         else if (rect)
1166             TRACE( "%p rect %s ", hwnd, wine_dbgstr_rect(rect) );
1167         else
1168             TRACE( "%p whole window ", hwnd );
1169
1170         dump_rdw_flags(flags);
1171     }
1172
1173     /* process pending expose events before painting */
1174     if (flags & RDW_UPDATENOW) USER_Driver->pMsgWaitForMultipleObjectsEx( 0, NULL, 0, QS_PAINT, 0 );
1175
1176     if (rect && !hrgn)
1177     {
1178         if (IsRectEmpty( rect )) rect = &empty;
1179         ret = redraw_window_rects( hwnd, flags, rect, 1 );
1180     }
1181     else if (!hrgn)
1182     {
1183         ret = redraw_window_rects( hwnd, flags, NULL, 0 );
1184     }
1185     else  /* need to build a list of the region rectangles */
1186     {
1187         DWORD size;
1188         RGNDATA *data = NULL;
1189
1190         if (!(size = GetRegionData( hrgn, 0, NULL ))) return FALSE;
1191         if (!(data = HeapAlloc( GetProcessHeap(), 0, size ))) return FALSE;
1192         GetRegionData( hrgn, size, data );
1193         if (!data->rdh.nCount)  /* empty region -> use a single all-zero rectangle */
1194             ret = redraw_window_rects( hwnd, flags, &empty, 1 );
1195         else
1196             ret = redraw_window_rects( hwnd, flags, (const RECT *)data->Buffer, data->rdh.nCount );
1197         HeapFree( GetProcessHeap(), 0, data );
1198     }
1199
1200     if (flags & RDW_UPDATENOW) update_now( hwnd, flags );
1201     else if (flags & RDW_ERASENOW) erase_now( hwnd, flags );
1202
1203     return ret;
1204 }
1205
1206
1207 /***********************************************************************
1208  *              UpdateWindow (USER32.@)
1209  */
1210 BOOL WINAPI UpdateWindow( HWND hwnd )
1211 {
1212     return RedrawWindow( hwnd, NULL, 0, RDW_UPDATENOW | RDW_ALLCHILDREN );
1213 }
1214
1215
1216 /***********************************************************************
1217  *              InvalidateRgn (USER32.@)
1218  */
1219 BOOL WINAPI InvalidateRgn( HWND hwnd, HRGN hrgn, BOOL erase )
1220 {
1221     if (!hwnd)
1222     {
1223         SetLastError( ERROR_INVALID_WINDOW_HANDLE );
1224         return FALSE;
1225     }
1226
1227     return RedrawWindow(hwnd, NULL, hrgn, RDW_INVALIDATE | (erase ? RDW_ERASE : 0) );
1228 }
1229
1230
1231 /***********************************************************************
1232  *              InvalidateRect (USER32.@)
1233  *
1234  * MSDN: if hwnd parameter is NULL, InvalidateRect invalidates and redraws
1235  * all windows and sends WM_ERASEBKGND and WM_NCPAINT.
1236  */
1237 BOOL WINAPI InvalidateRect( HWND hwnd, const RECT *rect, BOOL erase )
1238 {
1239     UINT flags = RDW_INVALIDATE | (erase ? RDW_ERASE : 0);
1240
1241     if (!hwnd)
1242     {
1243         flags = RDW_ALLCHILDREN | RDW_INVALIDATE | RDW_FRAME | RDW_ERASE | RDW_ERASENOW;
1244         rect = NULL;
1245     }
1246
1247     return RedrawWindow( hwnd, rect, 0, flags );
1248 }
1249
1250
1251 /***********************************************************************
1252  *              ValidateRgn (USER32.@)
1253  */
1254 BOOL WINAPI ValidateRgn( HWND hwnd, HRGN hrgn )
1255 {
1256     if (!hwnd)
1257     {
1258         SetLastError( ERROR_INVALID_WINDOW_HANDLE );
1259         return FALSE;
1260     }
1261
1262     return RedrawWindow( hwnd, NULL, hrgn, RDW_VALIDATE );
1263 }
1264
1265
1266 /***********************************************************************
1267  *              ValidateRect (USER32.@)
1268  *
1269  * MSDN: if hwnd parameter is NULL, ValidateRect invalidates and redraws
1270  * all windows and sends WM_ERASEBKGND and WM_NCPAINT.
1271  */
1272 BOOL WINAPI ValidateRect( HWND hwnd, const RECT *rect )
1273 {
1274     UINT flags = RDW_VALIDATE;
1275
1276     if (!hwnd)
1277     {
1278         flags = RDW_ALLCHILDREN | RDW_INVALIDATE | RDW_FRAME | RDW_ERASE | RDW_ERASENOW;
1279         rect = NULL;
1280     }
1281
1282     return RedrawWindow( hwnd, rect, 0, flags );
1283 }
1284
1285
1286 /***********************************************************************
1287  *              GetUpdateRgn (USER32.@)
1288  */
1289 INT WINAPI GetUpdateRgn( HWND hwnd, HRGN hrgn, BOOL erase )
1290 {
1291     INT retval = ERROR;
1292     UINT flags = UPDATE_NOCHILDREN;
1293     HRGN update_rgn;
1294
1295     if (erase) flags |= UPDATE_NONCLIENT | UPDATE_ERASE;
1296
1297     if ((update_rgn = send_ncpaint( hwnd, NULL, &flags )))
1298     {
1299         POINT offset;
1300
1301         retval = CombineRgn( hrgn, update_rgn, 0, RGN_COPY );
1302         if (send_erase( hwnd, flags, update_rgn, NULL, NULL ))
1303         {
1304             flags = UPDATE_DELAYED_ERASE;
1305             get_update_flags( hwnd, NULL, &flags );
1306         }
1307         /* map region to client coordinates */
1308         offset.x = offset.y = 0;
1309         ScreenToClient( hwnd, &offset );
1310         OffsetRgn( hrgn, offset.x, offset.y );
1311     }
1312     return retval;
1313 }
1314
1315
1316 /***********************************************************************
1317  *              GetUpdateRect (USER32.@)
1318  */
1319 BOOL WINAPI GetUpdateRect( HWND hwnd, LPRECT rect, BOOL erase )
1320 {
1321     UINT flags = UPDATE_NOCHILDREN;
1322     HRGN update_rgn;
1323     BOOL need_erase;
1324
1325     if (erase) flags |= UPDATE_NONCLIENT | UPDATE_ERASE;
1326
1327     if (!(update_rgn = send_ncpaint( hwnd, NULL, &flags ))) return FALSE;
1328
1329     if (rect)
1330     {
1331         if (GetRgnBox( update_rgn, rect ) != NULLREGION)
1332         {
1333             HDC hdc = GetDCEx( hwnd, 0, DCX_USESTYLE );
1334             MapWindowPoints( 0, hwnd, (LPPOINT)rect, 2 );
1335             DPtoLP( hdc, (LPPOINT)rect, 2 );
1336             ReleaseDC( hwnd, hdc );
1337         }
1338     }
1339     need_erase = send_erase( hwnd, flags, update_rgn, NULL, NULL );
1340
1341     /* check if we still have an update region */
1342     flags = UPDATE_PAINT | UPDATE_NOCHILDREN;
1343     if (need_erase) flags |= UPDATE_DELAYED_ERASE;
1344     return (get_update_flags( hwnd, NULL, &flags ) && (flags & UPDATE_PAINT));
1345 }
1346
1347
1348 /***********************************************************************
1349  *              ExcludeUpdateRgn (USER32.@)
1350  */
1351 INT WINAPI ExcludeUpdateRgn( HDC hdc, HWND hwnd )
1352 {
1353     HRGN update_rgn = CreateRectRgn( 0, 0, 0, 0 );
1354     INT ret = GetUpdateRgn( hwnd, update_rgn, FALSE );
1355
1356     if (ret != ERROR)
1357     {
1358         POINT pt;
1359
1360         GetDCOrgEx( hdc, &pt );
1361         MapWindowPoints( 0, hwnd, &pt, 1 );
1362         OffsetRgn( update_rgn, -pt.x, -pt.y );
1363         ret = ExtSelectClipRgn( hdc, update_rgn, RGN_DIFF );
1364         DeleteObject( update_rgn );
1365     }
1366     return ret;
1367 }
1368
1369
1370 /*************************************************************************
1371  *              ScrollWindowEx (USER32.@)
1372  *
1373  * Note: contrary to what the doc says, pixels that are scrolled from the
1374  *      outside of clipRect to the inside are NOT painted.
1375  *
1376  */
1377 INT WINAPI ScrollWindowEx( HWND hwnd, INT dx, INT dy,
1378                            const RECT *rect, const RECT *clipRect,
1379                            HRGN hrgnUpdate, LPRECT rcUpdate,
1380                            UINT flags )
1381 {
1382     INT   retVal = NULLREGION;
1383     BOOL  bOwnRgn = TRUE;
1384     BOOL  bUpdate = (rcUpdate || hrgnUpdate || flags & (SW_INVALIDATE | SW_ERASE));
1385     int rdw_flags;
1386     HRGN  hrgnTemp;
1387     HRGN  hrgnWinupd = 0;
1388     HDC   hDC;
1389     RECT  rc, cliprc;
1390     HWND hwndCaret = NULL;
1391     BOOL moveCaret = FALSE;
1392     POINT newCaretPos;
1393
1394     TRACE( "%p, %d,%d hrgnUpdate=%p rcUpdate = %p %s %04x\n",
1395            hwnd, dx, dy, hrgnUpdate, rcUpdate, wine_dbgstr_rect(rect), flags );
1396     TRACE( "clipRect = %s\n", wine_dbgstr_rect(clipRect));
1397     if( flags & ~( SW_SCROLLCHILDREN | SW_INVALIDATE | SW_ERASE))
1398         FIXME("some flags (%04x) are unhandled\n", flags);
1399
1400     rdw_flags = (flags & SW_ERASE) && (flags & SW_INVALIDATE) ?
1401                                 RDW_INVALIDATE | RDW_ERASE  : RDW_INVALIDATE ;
1402
1403     if (!WIN_IsWindowDrawable( hwnd, TRUE )) return ERROR;
1404     hwnd = WIN_GetFullHandle( hwnd );
1405
1406     GetClientRect(hwnd, &rc);
1407     if (rect) IntersectRect(&rc, &rc, rect);
1408
1409     if (clipRect) IntersectRect(&cliprc,&rc,clipRect);
1410     else cliprc = rc;
1411
1412     if( hrgnUpdate ) bOwnRgn = FALSE;
1413     else if( bUpdate ) hrgnUpdate = CreateRectRgn( 0, 0, 0, 0 );
1414
1415     newCaretPos.x = newCaretPos.y = 0;
1416
1417     if( !IsRectEmpty(&cliprc) && (dx || dy)) {
1418         DWORD dcxflags = DCX_CACHE;
1419         DWORD style = GetWindowLongW( hwnd, GWL_STYLE );
1420
1421         hwndCaret = fix_caret(hwnd, &rc, dx, dy, flags, &moveCaret, &newCaretPos);
1422
1423         if( style & WS_CLIPSIBLINGS) dcxflags |= DCX_CLIPSIBLINGS;
1424         if( GetClassLongW( hwnd, GCL_STYLE ) & CS_PARENTDC)
1425             dcxflags |= DCX_PARENTCLIP;
1426         if( !(flags & SW_SCROLLCHILDREN) && (style & WS_CLIPCHILDREN))
1427             dcxflags |= DCX_CLIPCHILDREN;
1428         hDC = GetDCEx( hwnd, 0, dcxflags);
1429         if (hDC)
1430         {
1431             ScrollDC( hDC, dx, dy, &rc, &cliprc, hrgnUpdate, rcUpdate );
1432
1433             ReleaseDC( hwnd, hDC );
1434
1435             if (!bUpdate)
1436                 RedrawWindow( hwnd, NULL, hrgnUpdate, rdw_flags);
1437         }
1438
1439         /* If the windows has an update region, this must be
1440          * scrolled as well. Keep a copy in hrgnWinupd
1441          * to be added to hrngUpdate at the end. */
1442         hrgnTemp = CreateRectRgn( 0, 0, 0, 0 );
1443         retVal = GetUpdateRgn( hwnd, hrgnTemp, FALSE );
1444         if (retVal != NULLREGION)
1445         {
1446             HRGN hrgnClip = CreateRectRgnIndirect(&cliprc);
1447             if( !bOwnRgn) {
1448                 hrgnWinupd = CreateRectRgn( 0, 0, 0, 0);
1449                 CombineRgn( hrgnWinupd, hrgnTemp, 0, RGN_COPY);
1450             }
1451             OffsetRgn( hrgnTemp, dx, dy );
1452             CombineRgn( hrgnTemp, hrgnTemp, hrgnClip, RGN_AND );
1453             if( !bOwnRgn)
1454                 CombineRgn( hrgnWinupd, hrgnWinupd, hrgnTemp, RGN_OR );
1455             RedrawWindow( hwnd, NULL, hrgnTemp, rdw_flags);
1456
1457            /* Catch the case where the scrolling amount exceeds the size of the
1458             * original window. This generated a second update area that is the
1459             * location where the original scrolled content would end up.
1460             * This second region is not returned by the ScrollDC and sets
1461             * ScrollWindowEx apart from just a ScrollDC.
1462             *
1463             * This has been verified with testing on windows.
1464             */
1465             if (abs(dx) > abs(rc.right - rc.left) ||
1466                 abs(dy) > abs(rc.bottom - rc.top))
1467             {
1468                 SetRectRgn( hrgnTemp, rc.left + dx, rc.top + dy, rc.right+dx, rc.bottom + dy);
1469                 CombineRgn( hrgnTemp, hrgnTemp, hrgnClip, RGN_AND );
1470                 CombineRgn( hrgnUpdate, hrgnUpdate, hrgnTemp, RGN_OR );
1471
1472                 if( !bOwnRgn)
1473                     CombineRgn( hrgnWinupd, hrgnWinupd, hrgnTemp, RGN_OR );
1474             }
1475             DeleteObject( hrgnClip );
1476         }
1477         DeleteObject( hrgnTemp );
1478     } else {
1479         /* nothing was scrolled */
1480         if( !bOwnRgn)
1481             SetRectRgn( hrgnUpdate, 0, 0, 0, 0 );
1482         SetRectEmpty( rcUpdate);
1483     }
1484
1485     if( flags & SW_SCROLLCHILDREN )
1486     {
1487         HWND *list = WIN_ListChildren( hwnd );
1488         if (list)
1489         {
1490             int i;
1491             RECT r, dummy;
1492             for (i = 0; list[i]; i++)
1493             {
1494                 GetWindowRect( list[i], &r );
1495                 MapWindowPoints( 0, hwnd, (POINT *)&r, 2 );
1496                 if (!rect || IntersectRect(&dummy, &r, rect))
1497                     SetWindowPos( list[i], 0, r.left + dx, r.top  + dy, 0, 0,
1498                                   SWP_NOZORDER | SWP_NOSIZE | SWP_NOACTIVATE |
1499                                   SWP_NOREDRAW | SWP_DEFERERASE );
1500             }
1501             HeapFree( GetProcessHeap(), 0, list );
1502         }
1503     }
1504
1505     if( flags & (SW_INVALIDATE | SW_ERASE) )
1506         RedrawWindow( hwnd, NULL, hrgnUpdate, rdw_flags |
1507                       ((flags & SW_SCROLLCHILDREN) ? RDW_ALLCHILDREN : 0 ) );
1508
1509     if( hrgnWinupd) {
1510         CombineRgn( hrgnUpdate, hrgnUpdate, hrgnWinupd, RGN_OR);
1511         DeleteObject( hrgnWinupd);
1512     }
1513
1514     if( hwndCaret ) {
1515         if ( moveCaret ) SetCaretPos( newCaretPos.x, newCaretPos.y );
1516         ShowCaret(hwndCaret);
1517     }
1518
1519     if( bOwnRgn && hrgnUpdate ) DeleteObject( hrgnUpdate );
1520
1521     return retVal;
1522 }
1523
1524
1525 /*************************************************************************
1526  *              ScrollWindow (USER32.@)
1527  *
1528  */
1529 BOOL WINAPI ScrollWindow( HWND hwnd, INT dx, INT dy,
1530                           const RECT *rect, const RECT *clipRect )
1531 {
1532     return (ERROR != ScrollWindowEx( hwnd, dx, dy, rect, clipRect, 0, NULL,
1533                                      (rect ? 0 : SW_SCROLLCHILDREN) |
1534                                      SW_INVALIDATE | SW_ERASE ));
1535 }
1536
1537
1538 /*************************************************************************
1539  *              ScrollDC (USER32.@)
1540  *
1541  * dx, dy, lprcScroll and lprcClip are all in logical coordinates (msdn is
1542  * wrong) hrgnUpdate is returned in device coordinates with rcUpdate in
1543  * logical coordinates.
1544  */
1545 BOOL WINAPI ScrollDC( HDC hdc, INT dx, INT dy, const RECT *lprcScroll,
1546                       const RECT *lprcClip, HRGN hrgnUpdate, LPRECT lprcUpdate )
1547
1548 {
1549     return USER_Driver->pScrollDC( hdc, dx, dy, lprcScroll, lprcClip, hrgnUpdate, lprcUpdate );
1550 }