dlls/gdi/bitmap.c

   1 /*
   2  * GDI bitmap objects
   3  *
   4  * Copyright 1993 Alexandre Julliard
   5  *           1998 Huw D M Davies
   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include <stdlib.h>
  23 #include <string.h>
  24
  25 #include "wine/winbase16.h"
  26 #include "wine/wingdi16.h"
  27 #include "gdi.h"
  28 #include "gdi_private.h"
  29 #include "wine/debug.h"
  30
  31 WINE_DEFAULT_DEBUG_CHANNEL(bitmap);
  32
  33
  34 static HGDIOBJ BITMAP_SelectObject( HGDIOBJ handle, void *obj, HDC hdc );
  35 static INT BITMAP_GetObject16( HGDIOBJ handle, void *obj, INT count, LPVOID buffer );
  36 static INT BITMAP_GetObject( HGDIOBJ handle, void *obj, INT count, LPVOID buffer );
  37 static BOOL BITMAP_DeleteObject( HGDIOBJ handle, void *obj );
  38
  39 static const struct gdi_obj_funcs bitmap_funcs =
  40 {
  41     BITMAP_SelectObject,  /* pSelectObject */
  42     BITMAP_GetObject16,   /* pGetObject16 */
  43     BITMAP_GetObject,     /* pGetObjectA */
  44     BITMAP_GetObject,     /* pGetObjectW */
  45     NULL,                 /* pUnrealizeObject */
  46     BITMAP_DeleteObject   /* pDeleteObject */
  47 };
  48
  49 /***********************************************************************
  50  *           BITMAP_GetWidthBytes
  51  *
  52  * Return number of bytes taken by a scanline of 16-bit aligned Windows DDB
  53  * data.
  54  */
  55 INT BITMAP_GetWidthBytes( INT bmWidth, INT bpp )
  56 {
  57     switch(bpp)
  58     {
  59     case 1:
  60         return 2 * ((bmWidth+15) >> 4);
  61
  62     case 24:
  63         bmWidth *= 3; /* fall through */
  64     case 8:
  65         return bmWidth + (bmWidth & 1);
  66
  67     case 32:
  68         return bmWidth * 4;
  69
  70     case 16:
  71     case 15:
  72         return bmWidth * 2;
  73
  74     case 4:
  75         return 2 * ((bmWidth+3) >> 2);
  76
  77     default:
  78         WARN("Unknown depth %d, please report.\n", bpp );
  79     }
  80     return -1;
  81 }
  82
  83
  84 /******************************************************************************
  85  * CreateBitmap [GDI32.@]
  86  *
  87  * Creates a bitmap with the specified info.
  88  *
  89  * PARAMS
  90  *    width  [I] bitmap width
  91  *    height [I] bitmap height
  92  *    planes [I] Number of color planes
  93  *    bpp    [I] Number of bits to identify a color
  94  *    bits   [I] Pointer to array containing color data
  95  *
  96  * RETURNS
  97  *    Success: Handle to bitmap
  98  *    Failure: 0
  99  */
 100 HBITMAP WINAPI CreateBitmap( INT width, INT height, UINT planes,
 101                              UINT bpp, LPCVOID bits )
 102 {
 103     BITMAP bm;
 104
 105     bm.bmType = 0;
 106     bm.bmWidth = width;
 107     bm.bmHeight = height;
 108     bm.bmWidthBytes = BITMAP_GetWidthBytes( width, bpp );
 109     bm.bmPlanes = planes;
 110     bm.bmBitsPixel = bpp;
 111     bm.bmBits = (LPVOID)bits;
 112
 113     return CreateBitmapIndirect( &bm );
 114 }
 115
 116 /******************************************************************************
 117  * CreateCompatibleBitmap [GDI32.@]
 118  *
 119  * Creates a bitmap compatible with the DC.
 120  *
 121  * PARAMS
 122  *    hdc    [I] Handle to device context
 123  *    width  [I] Width of bitmap
 124  *    height [I] Height of bitmap
 125  *
 126  * RETURNS
 127  *    Success: Handle to bitmap
 128  *    Failure: 0
 129  */
 130 HBITMAP WINAPI CreateCompatibleBitmap( HDC hdc, INT width, INT height)
 131 {
 132     HBITMAP hbmpRet = 0;
 133     DC *dc;
 134
 135     TRACE("(%p,%d,%d) = \n", hdc, width, height);
 136
 137     if ((width >= 0x10000) || (height >= 0x10000))
 138     {
 139         FIXME("got bad width %d or height %d, please look for reason\n",
 140               width, height);
 141     }
 142     else
 143     {
 144         if (!(dc = DC_GetDCPtr(hdc))) return 0;
 145
 146         if (GDIMAGIC( dc->header.wMagic ) != MEMORY_DC_MAGIC)
 147         {
 148             hbmpRet = CreateBitmap(width, height,
 149                                    GetDeviceCaps(hdc, PLANES),
 150                                    GetDeviceCaps(hdc, BITSPIXEL),
 151                                    NULL);
 152         }
 153         else  /* Memory DC */
 154         {
 155             BITMAPOBJ *bmp = GDI_GetObjPtr( dc->hBitmap, BITMAP_MAGIC );
 156
 157             if (!bmp->dib)
 158             {
 159                 /* A device-dependent bitmap is selected in the DC */
 160                 hbmpRet = CreateBitmap(width, height,
 161                                        bmp->bitmap.bmPlanes,
 162                                        bmp->bitmap.bmBitsPixel,
 163                                        NULL);
 164             }
 165             else
 166             {
 167                 /* A DIB section is selected in the DC */
 168                 BITMAPINFO *bi;
 169                 void *bits;
 170
 171                 /* Allocate memory for a BITMAPINFOHEADER structure and a
 172                    color table. The maximum number of colors in a color table
 173                    is 256 which corresponds to a bitmap with depth 8.
 174                    Bitmaps with higher depths don't have color tables. */
 175                 bi = HeapAlloc(GetProcessHeap(), 0, sizeof(BITMAPINFOHEADER) + 256 * sizeof(RGBQUAD));
 176
 177                 if (bi)
 178                 {
 179                     bi->bmiHeader.biSize          = sizeof(bi->bmiHeader);
 180                     bi->bmiHeader.biWidth         = width;
 181                     bi->bmiHeader.biHeight        = height;
 182                     bi->bmiHeader.biPlanes        = bmp->dib->dsBmih.biPlanes;
 183                     bi->bmiHeader.biBitCount      = bmp->dib->dsBmih.biBitCount;
 184                     bi->bmiHeader.biCompression   = bmp->dib->dsBmih.biCompression;
 185                     bi->bmiHeader.biSizeImage     = 0;
 186                     bi->bmiHeader.biXPelsPerMeter = bmp->dib->dsBmih.biXPelsPerMeter;
 187                     bi->bmiHeader.biYPelsPerMeter = bmp->dib->dsBmih.biYPelsPerMeter;
 188                     bi->bmiHeader.biClrUsed       = bmp->dib->dsBmih.biClrUsed;
 189                     bi->bmiHeader.biClrImportant  = bmp->dib->dsBmih.biClrImportant;
 190
 191                     if (bi->bmiHeader.biCompression == BI_BITFIELDS)
 192                     {
 193                         /* Copy the color masks */
 194                         CopyMemory(bi->bmiColors, bmp->dib->dsBitfields, 3 * sizeof(DWORD));
 195                     }
 196                     else if (bi->bmiHeader.biBitCount <= 8)
 197                     {
 198                         /* Copy the color table */
 199                         GetDIBColorTable(hdc, 0, 256, bi->bmiColors);
 200                     }
 201
 202                     hbmpRet = CreateDIBSection(hdc, bi, DIB_RGB_COLORS, &bits, NULL, 0);
 203                     HeapFree(GetProcessHeap(), 0, bi);
 204                 }
 205             }
 206             GDI_ReleaseObj(dc->hBitmap);
 207         }
 208         GDI_ReleaseObj(hdc);
 209     }
 210
 211     TRACE("\t\t%p\n", hbmpRet);
 212     return hbmpRet;
 213 }
 214
 215
 216 /******************************************************************************
 217  * CreateBitmapIndirect [GDI32.@]
 218  *
 219  * Creates a bitmap with the specified info.
 220  *
 221  * PARAMS
 222  *  bmp [I] Pointer to the bitmap info describing the bitmap
 223  *
 224  * RETURNS
 225  *    Success: Handle to bitmap
 226  *    Failure: NULL. Use GetLastError() to determine the cause.
 227  *
 228  * NOTES
 229  *  If a width or height of 0 are given, a 1x1 monochrome bitmap is returned.
 230  */
 231 HBITMAP WINAPI CreateBitmapIndirect( const BITMAP *bmp )
 232 {
 233     BITMAP bm;
 234     BITMAPOBJ *bmpobj;
 235     HBITMAP hbitmap;
 236
 237     if (!bmp || bmp->bmType || bmp->bmPlanes != 1)
 238     {
 239         if (bmp && bmp->bmPlanes != 1)
 240             FIXME("planes = %d\n", bmp->bmPlanes);
 241         SetLastError( ERROR_INVALID_PARAMETER );
 242         return NULL;
 243     }
 244
 245     bm = *bmp;
 246
 247     if (!bm.bmWidth || !bm.bmHeight)
 248     {
 249         bm.bmWidth = bm.bmHeight = 1;
 250         bm.bmPlanes = bm.bmBitsPixel = 1;
 251         bm.bmWidthBytes = 2;
 252         bm.bmBits = NULL;
 253     }
 254     else
 255     {
 256         if (bm.bmHeight < 0)
 257             bm.bmHeight = -bm.bmHeight;
 258         if (bm.bmWidth < 0)
 259             bm.bmWidth = -bm.bmWidth;
 260     }
 261
 262       /* Create the BITMAPOBJ */
 263     bmpobj = GDI_AllocObject( sizeof(BITMAPOBJ), BITMAP_MAGIC,
 264                               (HGDIOBJ *)&hbitmap, &bitmap_funcs );
 265
 266     if (!bmpobj)
 267     {
 268         SetLastError( ERROR_NOT_ENOUGH_MEMORY );
 269         return NULL;
 270     }
 271
 272     TRACE("%dx%d, %d colors returning %p\n", bm.bmWidth, bm.bmHeight,
 273           1 << (bm.bmPlanes * bm.bmBitsPixel), hbitmap);
 274
 275     bmpobj->size.cx = 0;
 276     bmpobj->size.cy = 0;
 277     bmpobj->bitmap = bm;
 278     bmpobj->bitmap.bmBits = NULL;
 279     bmpobj->funcs = NULL;
 280     bmpobj->dib = NULL;
 281     bmpobj->segptr_bits = 0;
 282
 283     if (bm.bmBits)
 284         SetBitmapBits( hbitmap, bm.bmHeight * bm.bmWidthBytes, bm.bmBits );
 285
 286     GDI_ReleaseObj( hbitmap );
 287     return hbitmap;
 288 }
 289
 290
 291 /***********************************************************************
 292  * GetBitmapBits [GDI32.@]
 293  *
 294  * Copies bitmap bits of bitmap to buffer.
 295  *
 296  * RETURNS
 297  *    Success: Number of bytes copied
 298  *    Failure: 0
 299  */
 300 LONG WINAPI GetBitmapBits(
 301     HBITMAP hbitmap, /* [in]  Handle to bitmap */
 302     LONG count,        /* [in]  Number of bytes to copy */
 303     LPVOID bits)       /* [out] Pointer to buffer to receive bits */
 304 {
 305     BITMAPOBJ *bmp = (BITMAPOBJ *) GDI_GetObjPtr( hbitmap, BITMAP_MAGIC );
 306     LONG height, ret;
 307
 308     if (!bmp) return 0;
 309
 310     /* If the bits vector is null, the function should return the read size */
 311     if(bits == NULL)
 312     {
 313         ret = bmp->bitmap.bmWidthBytes * bmp->bitmap.bmHeight;
 314         goto done;
 315     }
 316
 317     if (count < 0) {
 318         WARN("(%ld): Negative number of bytes passed???\n", count );
 319         count = -count;
 320     }
 321
 322     /* Only get entire lines */
 323     height = count / bmp->bitmap.bmWidthBytes;
 324     if (height > bmp->bitmap.bmHeight) height = bmp->bitmap.bmHeight;
 325     count = height * bmp->bitmap.bmWidthBytes;
 326     if (count == 0)
 327       {
 328         WARN("Less than one entire line requested\n");
 329         ret = 0;
 330         goto done;
 331       }
 332
 333
 334     TRACE("(%p, %ld, %p) %dx%d %d colors fetched height: %ld\n",
 335           hbitmap, count, bits, bmp->bitmap.bmWidth, bmp->bitmap.bmHeight,
 336           1 << bmp->bitmap.bmBitsPixel, height );
 337
 338     if(bmp->funcs && bmp->funcs->pGetBitmapBits)
 339     {
 340         TRACE("Calling device specific BitmapBits\n");
 341         ret = bmp->funcs->pGetBitmapBits(hbitmap, bits, count);
 342     } else {
 343
 344         if(!bmp->bitmap.bmBits) {
 345             WARN("Bitmap is empty\n");
 346             ret = 0;
 347         } else {
 348             memcpy(bits, bmp->bitmap.bmBits, count);
 349             ret = count;
 350         }
 351
 352     }
 353  done:
 354     GDI_ReleaseObj( hbitmap );
 355     return ret;
 356 }
 357
 358
 359 /******************************************************************************
 360  * SetBitmapBits [GDI32.@]
 361  *
 362  * Sets bits of color data for a bitmap.
 363  *
 364  * RETURNS
 365  *    Success: Number of bytes used in setting the bitmap bits
 366  *    Failure: 0
 367  */
 368 LONG WINAPI SetBitmapBits(
 369     HBITMAP hbitmap, /* [in] Handle to bitmap */
 370     LONG count,        /* [in] Number of bytes in bitmap array */
 371     LPCVOID bits)      /* [in] Address of array with bitmap bits */
 372 {
 373     BITMAPOBJ *bmp = (BITMAPOBJ *) GDI_GetObjPtr( hbitmap, BITMAP_MAGIC );
 374     LONG height, ret;
 375
 376     if ((!bmp) || (!bits))
 377         return 0;
 378
 379     if (count < 0) {
 380         WARN("(%ld): Negative number of bytes passed???\n", count );
 381         count = -count;
 382     }
 383
 384     /* Only get entire lines */
 385     height = count / bmp->bitmap.bmWidthBytes;
 386     if (height > bmp->bitmap.bmHeight) height = bmp->bitmap.bmHeight;
 387     count = height * bmp->bitmap.bmWidthBytes;
 388
 389     TRACE("(%p, %ld, %p) %dx%d %d colors fetched height: %ld\n",
 390           hbitmap, count, bits, bmp->bitmap.bmWidth, bmp->bitmap.bmHeight,
 391           1 << bmp->bitmap.bmBitsPixel, height );
 392
 393     if(bmp->funcs && bmp->funcs->pSetBitmapBits) {
 394
 395         TRACE("Calling device specific BitmapBits\n");
 396         ret = bmp->funcs->pSetBitmapBits(hbitmap, bits, count);
 397     } else {
 398
 399         if(!bmp->bitmap.bmBits) /* Alloc enough for entire bitmap */
 400             bmp->bitmap.bmBits = HeapAlloc( GetProcessHeap(), 0, count );
 401         if(!bmp->bitmap.bmBits) {
 402             WARN("Unable to allocate bit buffer\n");
 403             ret = 0;
 404         } else {
 405             memcpy(bmp->bitmap.bmBits, bits, count);
 406             ret = count;
 407         }
 408     }
 409
 410     GDI_ReleaseObj( hbitmap );
 411     return ret;
 412 }
 413
 414 /**********************************************************************
 415  *              BITMAP_CopyBitmap
 416  *
 417  */
 418 HBITMAP BITMAP_CopyBitmap(HBITMAP hbitmap)
 419 {
 420     BITMAPOBJ *bmp = (BITMAPOBJ *) GDI_GetObjPtr( hbitmap, BITMAP_MAGIC );
 421     HBITMAP res = 0;
 422     BITMAP bm;
 423
 424     if(!bmp) return 0;
 425
 426     bm = bmp->bitmap;
 427     bm.bmBits = NULL;
 428     res = CreateBitmapIndirect(&bm);
 429
 430     if(res) {
 431         char *buf = HeapAlloc( GetProcessHeap(), 0, bm.bmWidthBytes *
 432                                bm.bmHeight );
 433         GetBitmapBits (hbitmap, bm.bmWidthBytes * bm.bmHeight, buf);
 434         SetBitmapBits (res, bm.bmWidthBytes * bm.bmHeight, buf);
 435         HeapFree( GetProcessHeap(), 0, buf );
 436     }
 437
 438     GDI_ReleaseObj( hbitmap );
 439     return res;
 440 }
 441
 442
 443 /***********************************************************************
 444  *           BITMAP_SetOwnerDC
 445  *
 446  * Set the type of DC that owns the bitmap. This is used when the
 447  * bitmap is selected into a device to initialize the bitmap function
 448  * table.
 449  */
 450 BOOL BITMAP_SetOwnerDC( HBITMAP hbitmap, DC *dc )
 451 {
 452     BITMAPOBJ *bitmap;
 453     BOOL ret;
 454
 455     /* never set the owner of the stock bitmap since it can be selected in multiple DCs */
 456     if (hbitmap == GetStockObject(DEFAULT_BITMAP)) return TRUE;
 457
 458     if (!(bitmap = GDI_GetObjPtr( hbitmap, BITMAP_MAGIC ))) return FALSE;
 459
 460     ret = TRUE;
 461     if (!bitmap->funcs)  /* not owned by a DC yet */
 462     {
 463         if (dc->funcs->pCreateBitmap) ret = dc->funcs->pCreateBitmap( dc->physDev, hbitmap );
 464         if (ret) bitmap->funcs = dc->funcs;
 465     }
 466     else if (bitmap->funcs != dc->funcs)
 467     {
 468         FIXME( "Trying to select bitmap %p in different DC type\n", hbitmap );
 469         ret = FALSE;
 470     }
 471     GDI_ReleaseObj( hbitmap );
 472     return ret;
 473 }
 474
 475
 476 /***********************************************************************
 477  *           BITMAP_SelectObject
 478  */
 479 static HGDIOBJ BITMAP_SelectObject( HGDIOBJ handle, void *obj, HDC hdc )
 480 {
 481     HGDIOBJ ret;
 482     BITMAPOBJ *bitmap = obj;
 483     DC *dc = DC_GetDCPtr( hdc );
 484
 485     if (!dc) return 0;
 486     if (GetObjectType( hdc ) != OBJ_MEMDC)
 487     {
 488         GDI_ReleaseObj( hdc );
 489         return 0;
 490     }
 491     ret = dc->hBitmap;
 492     if (handle == dc->hBitmap) goto done;  /* nothing to do */
 493
 494     if (bitmap->header.dwCount && (handle != GetStockObject(DEFAULT_BITMAP)))
 495     {
 496         WARN( "Bitmap already selected in another DC\n" );
 497         GDI_ReleaseObj( hdc );
 498         return 0;
 499     }
 500
 501     if (!bitmap->funcs && !BITMAP_SetOwnerDC( handle, dc ))
 502     {
 503         GDI_ReleaseObj( hdc );
 504         return 0;
 505     }
 506
 507     if (dc->funcs->pSelectBitmap) handle = dc->funcs->pSelectBitmap( dc->physDev, handle );
 508
 509     if (handle)
 510     {
 511         dc->hBitmap = handle;
 512         dc->flags &= ~DC_DIRTY;
 513         SetRectRgn( dc->hVisRgn, 0, 0, bitmap->bitmap.bmWidth, bitmap->bitmap.bmHeight);
 514         DC_InitDC( dc );
 515     }
 516     else ret = 0;
 517
 518  done:
 519     GDI_ReleaseObj( hdc );
 520     return ret;
 521 }
 522
 523
 524 /***********************************************************************
 525  *           BITMAP_DeleteObject
 526  */
 527 static BOOL BITMAP_DeleteObject( HGDIOBJ handle, void *obj )
 528 {
 529     BITMAPOBJ * bmp = obj;
 530
 531     if (bmp->funcs && bmp->funcs->pDeleteBitmap)
 532         bmp->funcs->pDeleteBitmap( handle );
 533
 534     HeapFree( GetProcessHeap(), 0, bmp->bitmap.bmBits );
 535
 536     if (bmp->dib)
 537     {
 538         DIBSECTION *dib = bmp->dib;
 539
 540         if (dib->dsBm.bmBits)
 541         {
 542             if (dib->dshSection)
 543             {
 544                 SYSTEM_INFO SystemInfo;
 545                 GetSystemInfo( &SystemInfo );
 546                 UnmapViewOfFile( (char *)dib->dsBm.bmBits -
 547                                  (dib->dsOffset % SystemInfo.dwAllocationGranularity) );
 548             }
 549             else if (!dib->dsOffset)
 550                 VirtualFree(dib->dsBm.bmBits, 0L, MEM_RELEASE );
 551         }
 552         HeapFree(GetProcessHeap(), 0, dib);
 553         bmp->dib = NULL;
 554         if (bmp->segptr_bits)
 555         { /* free its selector array */
 556             WORD sel = SELECTOROF(bmp->segptr_bits);
 557             WORD count = (GetSelectorLimit16(sel) / 0x10000) + 1;
 558             int i;
 559
 560             for (i = 0; i < count; i++) FreeSelector16(sel + (i << __AHSHIFT));
 561         }
 562     }
 563     return GDI_FreeObject( handle, obj );
 564 }
 565
 566
 567 /***********************************************************************
 568  *           BITMAP_GetObject16
 569  */
 570 static INT BITMAP_GetObject16( HGDIOBJ handle, void *obj, INT count, LPVOID buffer )
 571 {
 572     BITMAPOBJ *bmp = obj;
 573
 574     if (bmp->dib)
 575     {
 576         if ( count <= sizeof(BITMAP16) )
 577         {
 578             BITMAP *bmp32 = &bmp->dib->dsBm;
 579             BITMAP16 bmp16;
 580             bmp16.bmType       = bmp32->bmType;
 581             bmp16.bmWidth      = bmp32->bmWidth;
 582             bmp16.bmHeight     = bmp32->bmHeight;
 583             bmp16.bmWidthBytes = bmp32->bmWidthBytes;
 584             bmp16.bmPlanes     = bmp32->bmPlanes;
 585             bmp16.bmBitsPixel  = bmp32->bmBitsPixel;
 586             bmp16.bmBits       = (SEGPTR)0;
 587             memcpy( buffer, &bmp16, count );
 588             return count;
 589         }
 590         else
 591         {
 592             FIXME("not implemented for DIBs: count %d\n", count);
 593             return 0;
 594         }
 595     }
 596     else
 597     {
 598         BITMAP16 bmp16;
 599         bmp16.bmType       = bmp->bitmap.bmType;
 600         bmp16.bmWidth      = bmp->bitmap.bmWidth;
 601         bmp16.bmHeight     = bmp->bitmap.bmHeight;
 602         bmp16.bmWidthBytes = bmp->bitmap.bmWidthBytes;
 603         bmp16.bmPlanes     = bmp->bitmap.bmPlanes;
 604         bmp16.bmBitsPixel  = bmp->bitmap.bmBitsPixel;
 605         bmp16.bmBits       = (SEGPTR)0;
 606         if (count > sizeof(bmp16)) count = sizeof(bmp16);
 607         memcpy( buffer, &bmp16, count );
 608         return count;
 609     }
 610 }
 611
 612
 613 /***********************************************************************
 614  *           BITMAP_GetObject
 615  */
 616 static INT BITMAP_GetObject( HGDIOBJ handle, void *obj, INT count, LPVOID buffer )
 617 {
 618     BITMAPOBJ *bmp = obj;
 619
 620     if (bmp->dib)
 621     {
 622         if( !buffer )
 623             return sizeof(DIBSECTION);
 624         if (count < sizeof(DIBSECTION))
 625         {
 626             if (count > sizeof(BITMAP)) count = sizeof(BITMAP);
 627         }
 628         else
 629         {
 630             if (count > sizeof(DIBSECTION)) count = sizeof(DIBSECTION);
 631         }
 632
 633         memcpy( buffer, bmp->dib, count );
 634         return count;
 635     }
 636     else
 637     {
 638         if( !buffer )
 639             return sizeof(BITMAP);
 640         if (count > sizeof(BITMAP)) count = sizeof(BITMAP);
 641         memcpy( buffer, &bmp->bitmap, count );
 642         return count;
 643     }
 644 }
 645
 646
 647 /******************************************************************************
 648  * CreateDiscardableBitmap [GDI32.@]
 649  *
 650  * Creates a discardable bitmap.
 651  *
 652  * RETURNS
 653  *    Success: Handle to bitmap
 654  *    Failure: NULL
 655  */
 656 HBITMAP WINAPI CreateDiscardableBitmap(
 657     HDC hdc,    /* [in] Handle to device context */
 658     INT width,  /* [in] Bitmap width */
 659     INT height) /* [in] Bitmap height */
 660 {
 661     return CreateCompatibleBitmap( hdc, width, height );
 662 }
 663
 664
 665 /******************************************************************************
 666  * GetBitmapDimensionEx [GDI32.@]
 667  *
 668  * Retrieves dimensions of a bitmap.
 669  *
 670  * RETURNS
 671  *    Success: TRUE
 672  *    Failure: FALSE
 673  */
 674 BOOL WINAPI GetBitmapDimensionEx(
 675     HBITMAP hbitmap, /* [in]  Handle to bitmap */
 676     LPSIZE size)     /* [out] Address of struct receiving dimensions */
 677 {
 678     BITMAPOBJ * bmp = (BITMAPOBJ *) GDI_GetObjPtr( hbitmap, BITMAP_MAGIC );
 679     if (!bmp) return FALSE;
 680     *size = bmp->size;
 681     GDI_ReleaseObj( hbitmap );
 682     return TRUE;
 683 }
 684
 685
 686 /******************************************************************************
 687  * SetBitmapDimensionEx [GDI32.@]
 688  *
 689  * Assigns dimensions to a bitmap.
 690  * MSDN says that this function will fail if hbitmap is a handle created by
 691  * CreateDIBSection, but that's not true on Windows 2000.
 692  *
 693  * RETURNS
 694  *    Success: TRUE
 695  *    Failure: FALSE
 696  */
 697 BOOL WINAPI SetBitmapDimensionEx(
 698     HBITMAP hbitmap, /* [in]  Handle to bitmap */
 699     INT x,           /* [in]  Bitmap width */
 700     INT y,           /* [in]  Bitmap height */
 701     LPSIZE prevSize) /* [out] Address of structure for orig dims */
 702 {
 703     BITMAPOBJ * bmp = (BITMAPOBJ *) GDI_GetObjPtr( hbitmap, BITMAP_MAGIC );
 704     if (!bmp) return FALSE;
 705     if (prevSize) *prevSize = bmp->size;
 706     bmp->size.cx = x;
 707     bmp->size.cy = y;
 708     GDI_ReleaseObj( hbitmap );
 709     return TRUE;
 710 }