dlls/x11drv/dce.c

   1 /*
   2 * USER DCE functions
   3  *
   4  * Copyright 1993, 2005 Alexandre Julliard
   5  * Copyright 1996, 1997 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
  24 #include <assert.h>
  25 #include "ntstatus.h"
  26 #define WIN32_NO_STATUS
  27 #include "win.h"
  28 #include "windef.h"
  29 #include "wingdi.h"
  30 #include "wownt32.h"
  31 #include "x11drv.h"
  32 #include "wine/winbase16.h"
  33 #include "wine/wingdi16.h"
  34 #include "wine/server.h"
  35 #include "wine/list.h"
  36 #include "wine/debug.h"
  37
  38 WINE_DEFAULT_DEBUG_CHANNEL(dc);
  39
  40 struct dce
  41 {
  42     struct list entry;         /* entry in global DCE list */
  43     HDC         hdc;
  44     HWND        hwnd;
  45     HRGN        clip_rgn;
  46     DWORD       flags;
  47     void       *class_ptr;     /* ptr to identify window class for class DCEs */
  48     ULONG       count;         /* usage count; 0 or 1 for cache DCEs, always 1 for window DCEs,
  49                                   always >= 1 for class DCEs */
  50 };
  51
  52 static struct list dce_list = LIST_INIT(dce_list);
  53
  54 static BOOL16 CALLBACK dc_hook( HDC16 hDC, WORD code, DWORD data, LPARAM lParam );
  55
  56 static CRITICAL_SECTION dce_section;
  57 static CRITICAL_SECTION_DEBUG critsect_debug =
  58 {
  59     0, 0, &dce_section,
  60     { &critsect_debug.ProcessLocksList, &critsect_debug.ProcessLocksList },
  61       0, 0, { (DWORD_PTR)(__FILE__ ": dce_section") }
  62 };
  63 static CRITICAL_SECTION dce_section = { &critsect_debug, -1, 0, 0, 0, 0 };
  64
  65 static const WCHAR displayW[] = { 'D','I','S','P','L','A','Y',0 };
  66
  67
  68 /***********************************************************************
  69  *           dump_cache
  70  */
  71 static void dump_cache(void)
  72 {
  73     struct dce *dce;
  74
  75     EnterCriticalSection( &dce_section );
  76
  77     LIST_FOR_EACH_ENTRY( dce, &dce_list, struct dce, entry )
  78     {
  79         TRACE("%p: hwnd %p dcx %08lx %s %s\n",
  80               dce, dce->hwnd, dce->flags,
  81               (dce->flags & DCX_CACHE) ? "Cache" : "Owned",
  82               dce->count ? "InUse" : "" );
  83     }
  84
  85     LeaveCriticalSection( &dce_section );
  86 }
  87
  88
  89 /***********************************************************************
  90  *              update_visible_region
  91  *
  92  * Set the visible region and X11 drawable for the DC associated to
  93  * a given window.
  94  */
  95 static void update_visible_region( struct dce *dce )
  96 {
  97     NTSTATUS status;
  98     HRGN vis_rgn = 0;
  99     HWND top = 0;
 100     struct x11drv_escape_set_drawable escape;
 101     struct x11drv_win_data *data;
 102     DWORD flags = dce->flags;
 103     size_t size = 256;
 104
 105     /* don't clip siblings if using parent clip region */
 106     if (flags & DCX_PARENTCLIP) flags &= ~DCX_CLIPSIBLINGS;
 107
 108     /* fetch the visible region from the server */
 109     do
 110     {
 111         RGNDATA *data = HeapAlloc( GetProcessHeap(), 0, sizeof(*data) + size - 1 );
 112         if (!data) return;
 113
 114         SERVER_START_REQ( get_visible_region )
 115         {
 116             req->window  = dce->hwnd;
 117             req->flags   = flags;
 118             wine_server_set_reply( req, data->Buffer, size );
 119             if (!(status = wine_server_call( req )))
 120             {
 121                 size_t reply_size = wine_server_reply_size( reply );
 122                 data->rdh.dwSize   = sizeof(data->rdh);
 123                 data->rdh.iType    = RDH_RECTANGLES;
 124                 data->rdh.nCount   = reply_size / sizeof(RECT);
 125                 data->rdh.nRgnSize = reply_size;
 126                 vis_rgn = ExtCreateRegion( NULL, size, data );
 127
 128                 top = reply->top_win;
 129                 escape.org.x = reply->win_org_x - reply->top_org_x;
 130                 escape.org.y = reply->win_org_y - reply->top_org_y;
 131                 escape.drawable_org.x = reply->top_org_x;
 132                 escape.drawable_org.y = reply->top_org_y;
 133             }
 134             else size = reply->total_size;
 135         }
 136         SERVER_END_REQ;
 137         HeapFree( GetProcessHeap(), 0, data );
 138     } while (status == STATUS_BUFFER_OVERFLOW);
 139
 140     if (status || !vis_rgn) return;
 141
 142     if (dce->clip_rgn) CombineRgn( vis_rgn, vis_rgn, dce->clip_rgn,
 143                                    (flags & DCX_INTERSECTRGN) ? RGN_AND : RGN_DIFF );
 144
 145     if (top == dce->hwnd && ((data = X11DRV_get_win_data( dce->hwnd )) != NULL) &&
 146          IsIconic( dce->hwnd ) && data->icon_window)
 147         escape.drawable = data->icon_window;
 148     else
 149         escape.drawable = X11DRV_get_whole_window( top );
 150
 151     escape.code = X11DRV_SET_DRAWABLE;
 152     escape.mode = IncludeInferiors;
 153     ExtEscape( dce->hdc, X11DRV_ESCAPE, sizeof(escape), (LPSTR)&escape, 0, NULL );
 154
 155     /* map region to DC coordinates */
 156     OffsetRgn( vis_rgn,
 157                -(escape.drawable_org.x + escape.org.x),
 158                -(escape.drawable_org.y + escape.org.y) );
 159     SelectVisRgn16( HDC_16(dce->hdc), HRGN_16(vis_rgn) );
 160     DeleteObject( vis_rgn );
 161 }
 162
 163
 164 /***********************************************************************
 165  *              release_dce
 166  */
 167 static void release_dce( struct dce *dce )
 168 {
 169     struct x11drv_escape_set_drawable escape;
 170
 171     if (!dce->hwnd) return;  /* already released */
 172
 173     if (dce->clip_rgn) DeleteObject( dce->clip_rgn );
 174     dce->clip_rgn = 0;
 175     dce->hwnd     = 0;
 176     dce->flags   &= DCX_CACHE;
 177
 178     escape.code = X11DRV_SET_DRAWABLE;
 179     escape.drawable = root_window;
 180     escape.mode = IncludeInferiors;
 181     escape.org.x = escape.org.y = 0;
 182     escape.drawable_org.x = escape.drawable_org.y = 0;
 183     ExtEscape( dce->hdc, X11DRV_ESCAPE, sizeof(escape), (LPSTR)&escape, 0, NULL );
 184 }
 185
 186
 187 /***********************************************************************
 188  *   delete_clip_rgn
 189  */
 190 static void delete_clip_rgn( struct dce *dce )
 191 {
 192     if (!dce->clip_rgn) return;  /* nothing to do */
 193
 194     dce->flags &= ~(DCX_EXCLUDERGN | DCX_INTERSECTRGN);
 195     DeleteObject( dce->clip_rgn );
 196     dce->clip_rgn = 0;
 197
 198     /* make it dirty so that the vis rgn gets recomputed next time */
 199     SetHookFlags16( HDC_16(dce->hdc), DCHF_INVALIDATEVISRGN );
 200 }
 201
 202
 203 /***********************************************************************
 204  *           alloc_cache_dce
 205  *
 206  * Allocate a new cache DCE.
 207  */
 208 static struct dce *alloc_cache_dce(void)
 209 {
 210     struct x11drv_escape_set_dce escape;
 211     struct dce *dce;
 212
 213     if (!(dce = HeapAlloc( GetProcessHeap(), 0, sizeof(*dce) ))) return NULL;
 214     if (!(dce->hdc = CreateDCW( displayW, NULL, NULL, NULL )))
 215     {
 216         HeapFree( GetProcessHeap(), 0, dce );
 217         return 0;
 218     }
 219     SaveDC( dce->hdc );
 220
 221     /* store DCE handle in DC hook data field */
 222     SetDCHook( dce->hdc, dc_hook, (DWORD)dce );
 223
 224     dce->hwnd      = 0;
 225     dce->clip_rgn  = 0;
 226     dce->flags     = DCX_CACHE;
 227     dce->class_ptr = NULL;
 228     dce->count     = 1;
 229
 230     EnterCriticalSection( &dce_section );
 231     list_add_head( &dce_list, &dce->entry );
 232     LeaveCriticalSection( &dce_section );
 233
 234     escape.code = X11DRV_SET_DCE;
 235     escape.dce  = dce;
 236     ExtEscape( dce->hdc, X11DRV_ESCAPE, sizeof(escape), (LPCSTR)&escape, 0, NULL );
 237
 238     return dce;
 239 }
 240
 241
 242 /***********************************************************************
 243  *           alloc_window_dce
 244  *
 245  * Allocate a DCE for a newly created window if necessary.
 246  */
 247 void alloc_window_dce( struct x11drv_win_data *data )
 248 {
 249     struct x11drv_escape_set_dce escape;
 250     struct dce *dce;
 251     void *class_ptr = NULL;
 252     LONG style = GetClassLongW( data->hwnd, GCL_STYLE );
 253
 254     if (!(style & (CS_CLASSDC|CS_OWNDC))) return;  /* nothing to do */
 255
 256     if (!(style & CS_OWNDC))  /* class dc */
 257     {
 258         /* hack: get the class pointer from the window structure */
 259         WND *win = WIN_GetPtr( data->hwnd );
 260         class_ptr = win->class;
 261         WIN_ReleasePtr( win );
 262
 263         EnterCriticalSection( &dce_section );
 264         LIST_FOR_EACH_ENTRY( dce, &dce_list, struct dce, entry )
 265         {
 266             if (dce->class_ptr == class_ptr)
 267             {
 268                 dce->count++;
 269                 data->dce = dce;
 270                 LeaveCriticalSection( &dce_section );
 271                 return;
 272             }
 273         }
 274         LeaveCriticalSection( &dce_section );
 275     }
 276
 277     /* now allocate a new one */
 278
 279     if (!(dce = HeapAlloc( GetProcessHeap(), 0, sizeof(*dce) ))) return;
 280     if (!(dce->hdc = CreateDCW( displayW, NULL, NULL, NULL )))
 281     {
 282         HeapFree( GetProcessHeap(), 0, dce );
 283         return;
 284     }
 285
 286     /* store DCE handle in DC hook data field */
 287
 288     SetDCHook( dce->hdc, dc_hook, (DWORD)dce );
 289
 290     dce->hwnd      = data->hwnd;
 291     dce->clip_rgn  = 0;
 292     dce->flags     = 0;
 293     dce->class_ptr = class_ptr;
 294     dce->count     = 1;
 295
 296     if (style & CS_OWNDC)
 297     {
 298         LONG win_style = GetWindowLongW( data->hwnd, GWL_STYLE );
 299         if (win_style & WS_CLIPCHILDREN) dce->flags |= DCX_CLIPCHILDREN;
 300         if (win_style & WS_CLIPSIBLINGS) dce->flags |= DCX_CLIPSIBLINGS;
 301     }
 302     SetHookFlags16( HDC_16(dce->hdc), DCHF_INVALIDATEVISRGN );
 303
 304     EnterCriticalSection( &dce_section );
 305     list_add_tail( &dce_list, &dce->entry );
 306     LeaveCriticalSection( &dce_section );
 307     data->dce = dce;
 308
 309     escape.code = X11DRV_SET_DCE;
 310     escape.dce  = dce;
 311     ExtEscape( dce->hdc, X11DRV_ESCAPE, sizeof(escape), (LPCSTR)&escape, 0, NULL );
 312 }
 313
 314
 315 /***********************************************************************
 316  *           free_window_dce
 317  *
 318  * Free a class or window DCE.
 319  */
 320 void free_window_dce( struct x11drv_win_data *data )
 321 {
 322     struct dce *dce = data->dce;
 323
 324     if (dce)
 325     {
 326         EnterCriticalSection( &dce_section );
 327         if (!--dce->count)
 328         {
 329             list_remove( &dce->entry );
 330             SetDCHook(dce->hdc, NULL, 0L);
 331             DeleteDC( dce->hdc );
 332             if (dce->clip_rgn) DeleteObject( dce->clip_rgn );
 333             HeapFree( GetProcessHeap(), 0, dce );
 334         }
 335         else if (dce->hwnd == data->hwnd)
 336         {
 337             release_dce( dce );
 338         }
 339         LeaveCriticalSection( &dce_section );
 340         data->dce = NULL;
 341     }
 342
 343     /* now check for cache DCEs */
 344
 345     EnterCriticalSection( &dce_section );
 346     LIST_FOR_EACH_ENTRY( dce, &dce_list, struct dce, entry )
 347     {
 348         if (dce->hwnd != data->hwnd) continue;
 349         if (!(dce->flags & DCX_CACHE)) continue;
 350
 351         if (dce->count) WARN( "GetDC() without ReleaseDC() for window %p\n", data->hwnd );
 352         release_dce( dce );
 353         dce->count = 0;
 354     }
 355     LeaveCriticalSection( &dce_section );
 356 }
 357
 358
 359 /***********************************************************************
 360  *   invalidate_dce
 361  *
 362  * It is called from SetWindowPos() - we have to
 363  * mark as dirty all busy DCEs for windows that have pWnd->parent as
 364  * an ancestor and whose client rect intersects with specified update
 365  * rectangle. In addition, pWnd->parent DCEs may need to be updated if
 366  * DCX_CLIPCHILDREN flag is set.
 367  */
 368 void invalidate_dce( HWND hwnd, const RECT *rect )
 369 {
 370     HWND hwndScope = GetAncestor( hwnd, GA_PARENT );
 371
 372     if( hwndScope )
 373     {
 374         struct dce *dce;
 375
 376         TRACE("scope hwnd = %p %s\n", hwndScope, wine_dbgstr_rect(rect) );
 377         if (TRACE_ON(dc)) dump_cache();
 378
 379         /* walk all DCEs and fixup non-empty entries */
 380
 381         LIST_FOR_EACH_ENTRY( dce, &dce_list, struct dce, entry )
 382         {
 383             if (!dce->hwnd) continue;
 384             if ((dce->hwnd == hwndScope) && !(dce->flags & DCX_CLIPCHILDREN))
 385                 continue;  /* child window positions don't bother us */
 386
 387             /* check if DCE window is within the z-order scope */
 388
 389             if (hwndScope == dce->hwnd || IsChild( hwndScope, dce->hwnd ))
 390             {
 391                 if (hwnd != dce->hwnd)
 392                 {
 393                     /* check if the window rectangle intersects this DCE window */
 394                     RECT tmp;
 395                     GetWindowRect( dce->hwnd, &tmp );
 396                     MapWindowPoints( 0, hwndScope, (POINT *)&tmp, 2 );
 397                     if (!IntersectRect( &tmp, &tmp, rect )) continue;
 398
 399                 }
 400                 if (!dce->count)
 401                 {
 402                     /* Don't bother with visible regions of unused DCEs */
 403
 404                     TRACE("\tpurged %p dce [%p]\n", dce, dce->hwnd);
 405                     release_dce( dce );
 406                 }
 407                 else
 408                 {
 409                     /* Set dirty bits in the hDC and DCE structs */
 410
 411                     TRACE("\tfixed up %p dce [%p]\n", dce, dce->hwnd);
 412                     SetHookFlags16( HDC_16(dce->hdc), DCHF_INVALIDATEVISRGN );
 413                 }
 414             }
 415         } /* dce list */
 416     }
 417 }
 418
 419
 420 /***********************************************************************
 421  *              X11DRV_GetDCEx   (X11DRV.@)
 422  *
 423  * Unimplemented flags: DCX_LOCKWINDOWUPDATE
 424  */
 425 HDC X11DRV_GetDCEx( HWND hwnd, HRGN hrgnClip, DWORD flags )
 426 {
 427     static const DWORD clip_flags = DCX_PARENTCLIP | DCX_CLIPSIBLINGS | DCX_CLIPCHILDREN | DCX_WINDOW;
 428
 429     struct x11drv_win_data *data = X11DRV_get_win_data( hwnd );
 430     struct dce *dce;
 431     BOOL bUpdateVisRgn = TRUE;
 432     HWND parent;
 433     LONG window_style = GetWindowLongW( hwnd, GWL_STYLE );
 434
 435     TRACE("hwnd %p, hrgnClip %p, flags %08lx\n", hwnd, hrgnClip, flags);
 436
 437     /* fixup flags */
 438
 439     if (flags & (DCX_WINDOW | DCX_PARENTCLIP)) flags |= DCX_CACHE;
 440
 441     if (flags & DCX_USESTYLE)
 442     {
 443         flags &= ~(DCX_CLIPCHILDREN | DCX_CLIPSIBLINGS | DCX_PARENTCLIP);
 444
 445         if (window_style & WS_CLIPSIBLINGS) flags |= DCX_CLIPSIBLINGS;
 446
 447         if (!(flags & DCX_WINDOW))
 448         {
 449             if (GetClassLongW( hwnd, GCL_STYLE ) & CS_PARENTDC) flags |= DCX_PARENTCLIP;
 450
 451             if (window_style & WS_CLIPCHILDREN && !(window_style & WS_MINIMIZE))
 452                 flags |= DCX_CLIPCHILDREN;
 453             if (!data || !data->dce) flags |= DCX_CACHE;
 454         }
 455     }
 456
 457     if (flags & DCX_WINDOW) flags &= ~DCX_CLIPCHILDREN;
 458
 459     parent = GetAncestor( hwnd, GA_PARENT );
 460     if (!parent || (parent == GetDesktopWindow()))
 461         flags = (flags & ~DCX_PARENTCLIP) | DCX_CLIPSIBLINGS;
 462
 463     /* it seems parent clip is ignored when clipping siblings or children */
 464     if (flags & (DCX_CLIPSIBLINGS | DCX_CLIPCHILDREN)) flags &= ~DCX_PARENTCLIP;
 465
 466     if( flags & DCX_PARENTCLIP )
 467     {
 468         LONG parent_style = GetWindowLongW( parent, GWL_STYLE );
 469         if( (window_style & WS_VISIBLE) && (parent_style & WS_VISIBLE) )
 470         {
 471             flags &= ~DCX_CLIPCHILDREN;
 472             if (parent_style & WS_CLIPSIBLINGS) flags |= DCX_CLIPSIBLINGS;
 473         }
 474     }
 475
 476     /* find a suitable DCE */
 477
 478     if (flags & DCX_CACHE)
 479     {
 480         struct dce *dceEmpty = NULL, *dceUnused = NULL;
 481
 482         /* Strategy: First, we attempt to find a non-empty but unused DCE with
 483          * compatible flags. Next, we look for an empty entry. If the cache is
 484          * full we have to purge one of the unused entries.
 485          */
 486         EnterCriticalSection( &dce_section );
 487         LIST_FOR_EACH_ENTRY( dce, &dce_list, struct dce, entry )
 488         {
 489             if ((dce->flags & DCX_CACHE) && !dce->count)
 490             {
 491                 dceUnused = dce;
 492
 493                 if (!dce->hwnd) dceEmpty = dce;
 494                 else if ((dce->hwnd == hwnd) && !((dce->flags ^ flags) & clip_flags))
 495                 {
 496                     TRACE("\tfound valid %p dce [%p], flags %08lx\n",
 497                           dce, hwnd, dce->flags );
 498                     bUpdateVisRgn = FALSE;
 499                     break;
 500                 }
 501             }
 502         }
 503
 504         if (&dce->entry == &dce_list)  /* nothing found */
 505             dce = dceEmpty ? dceEmpty : dceUnused;
 506
 507         if (dce) dce->count = 1;
 508
 509         LeaveCriticalSection( &dce_section );
 510
 511         /* if there's no dce empty or unused, allocate a new one */
 512         if (!dce) dce = alloc_cache_dce();
 513         if (!dce) return 0;
 514     }
 515     else
 516     {
 517         flags |= DCX_NORESETATTRS;
 518         dce = data->dce;
 519         if (dce->hwnd == hwnd)
 520         {
 521             TRACE("\tskipping hVisRgn update\n");
 522             bUpdateVisRgn = FALSE; /* updated automatically, via DCHook() */
 523         }
 524         else
 525         {
 526             /* we should free dce->clip_rgn here, but Windows apparently doesn't */
 527             dce->flags &= ~(DCX_EXCLUDERGN | DCX_INTERSECTRGN);
 528             dce->clip_rgn = 0;
 529         }
 530     }
 531
 532     if (flags & (DCX_INTERSECTRGN | DCX_EXCLUDERGN))
 533     {
 534         /* if the extra clip region has changed, get rid of the old one */
 535         if (dce->clip_rgn != hrgnClip || ((flags ^ dce->flags) & (DCX_INTERSECTRGN | DCX_EXCLUDERGN)))
 536             delete_clip_rgn( dce );
 537         dce->clip_rgn = hrgnClip;
 538         if (!dce->clip_rgn) dce->clip_rgn = CreateRectRgn( 0, 0, 0, 0 );
 539         dce->flags |= flags & (DCX_INTERSECTRGN | DCX_EXCLUDERGN);
 540         bUpdateVisRgn = TRUE;
 541     }
 542
 543     dce->hwnd = hwnd;
 544     dce->flags = (dce->flags & ~clip_flags) | (flags & clip_flags);
 545
 546     if (SetHookFlags16( HDC_16(dce->hdc), DCHF_VALIDATEVISRGN ))
 547         bUpdateVisRgn = TRUE;  /* DC was dirty */
 548
 549     if (bUpdateVisRgn) update_visible_region( dce );
 550
 551     if (!(flags & DCX_NORESETATTRS))
 552     {
 553         RestoreDC( dce->hdc, 1 );  /* initial save level is always 1 */
 554         SaveDC( dce->hdc );  /* save the state again for next time */
 555     }
 556
 557     TRACE("(%p,%p,0x%lx): returning %p\n", hwnd, hrgnClip, flags, dce->hdc);
 558     return dce->hdc;
 559 }
 560
 561
 562 /***********************************************************************
 563  *              X11DRV_ReleaseDC  (X11DRV.@)
 564  */
 565 INT X11DRV_ReleaseDC( HWND hwnd, HDC hdc, BOOL end_paint )
 566 {
 567     enum x11drv_escape_codes escape = X11DRV_GET_DCE;
 568     struct dce *dce;
 569     BOOL ret = FALSE;
 570
 571     TRACE("%p %p\n", hwnd, hdc );
 572
 573     EnterCriticalSection( &dce_section );
 574     if (!ExtEscape( hdc, X11DRV_ESCAPE, sizeof(escape), (LPCSTR)&escape,
 575                     sizeof(dce), (LPSTR)&dce )) dce = NULL;
 576     if (dce && dce->count)
 577     {
 578         if (end_paint || (dce->flags & DCX_CACHE)) delete_clip_rgn( dce );
 579         if (dce->flags & DCX_CACHE) dce->count = 0;
 580         ret = TRUE;
 581     }
 582     LeaveCriticalSection( &dce_section );
 583     return ret;
 584 }
 585
 586 /***********************************************************************
 587  *              dc_hook
 588  *
 589  * See "Undoc. Windows" for hints (DC, SetDCHook, SetHookFlags)..
 590  */
 591 static BOOL16 CALLBACK dc_hook( HDC16 hDC, WORD code, DWORD data, LPARAM lParam )
 592 {
 593     BOOL retv = TRUE;
 594     struct dce *dce = (struct dce *)data;
 595
 596     TRACE("hDC = %04x, %i\n", hDC, code);
 597
 598     if (!dce) return 0;
 599     assert( HDC_16(dce->hdc) == hDC );
 600
 601     switch( code )
 602     {
 603     case DCHC_INVALIDVISRGN:
 604         /* GDI code calls this when it detects that the
 605          * DC is dirty (usually after SetHookFlags()). This
 606          * means that we have to recompute the visible region.
 607          */
 608         if (dce->count) update_visible_region( dce );
 609         else /* non-fatal but shouldn't happen */
 610             WARN("DC is not in use!\n");
 611         break;
 612     case DCHC_DELETEDC:
 613         /*
 614          * Windows will not let you delete a DC that is busy
 615          * (between GetDC and ReleaseDC)
 616          */
 617         if (dce->count)
 618         {
 619             WARN("Application trying to delete a busy DC %p\n", dce->hdc);
 620             retv = FALSE;
 621         }
 622         else
 623         {
 624             EnterCriticalSection( &dce_section );
 625             list_remove( &dce->entry );
 626             LeaveCriticalSection( &dce_section );
 627             if (dce->clip_rgn) DeleteObject( dce->clip_rgn );
 628             HeapFree( GetProcessHeap(), 0, dce );
 629         }
 630         break;
 631     }
 632     return retv;
 633 }
 634
 635
 636 /**********************************************************************
 637  *              WindowFromDC   (X11DRV.@)
 638  */
 639 HWND X11DRV_WindowFromDC( HDC hdc )
 640 {
 641     enum x11drv_escape_codes escape = X11DRV_GET_DCE;
 642     struct dce *dce;
 643     HWND hwnd = 0;
 644
 645     EnterCriticalSection( &dce_section );
 646     if (!ExtEscape( hdc, X11DRV_ESCAPE, sizeof(escape), (LPCSTR)&escape,
 647                     sizeof(dce), (LPSTR)&dce )) dce = NULL;
 648     if (dce) hwnd = dce->hwnd;
 649     LeaveCriticalSection( &dce_section );
 650     return hwnd;
 651 }