wine/dlls/gdi32/bitmap.c

798 lines
22 KiB
C

/*
* GDI bitmap objects
*
* Copyright 1993 Alexandre Julliard
* 1998 Huw D M Davies
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
*/
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include "windef.h"
#include "winbase.h"
#include "wingdi.h"
#include "gdi_private.h"
#include "wine/debug.h"
WINE_DEFAULT_DEBUG_CHANNEL(bitmap);
static HGDIOBJ BITMAP_SelectObject( HGDIOBJ handle, HDC hdc );
static INT BITMAP_GetObject( HGDIOBJ handle, INT count, LPVOID buffer );
static BOOL BITMAP_DeleteObject( HGDIOBJ handle );
static const struct gdi_obj_funcs bitmap_funcs =
{
BITMAP_SelectObject, /* pSelectObject */
BITMAP_GetObject, /* pGetObjectA */
BITMAP_GetObject, /* pGetObjectW */
NULL, /* pUnrealizeObject */
BITMAP_DeleteObject /* pDeleteObject */
};
/***********************************************************************
* BITMAP_GetWidthBytes
*
* Return number of bytes taken by a scanline of 16-bit aligned Windows DDB
* data.
*/
INT BITMAP_GetWidthBytes( INT bmWidth, INT bpp )
{
switch(bpp)
{
case 1:
return 2 * ((bmWidth+15) >> 4);
case 24:
bmWidth *= 3; /* fall through */
case 8:
return bmWidth + (bmWidth & 1);
case 32:
return bmWidth * 4;
case 16:
case 15:
return bmWidth * 2;
case 4:
return 2 * ((bmWidth+3) >> 2);
default:
WARN("Unknown depth %d, please report.\n", bpp );
}
return -1;
}
/******************************************************************************
* CreateBitmap [GDI32.@]
*
* Creates a bitmap with the specified info.
*
* PARAMS
* width [I] bitmap width
* height [I] bitmap height
* planes [I] Number of color planes
* bpp [I] Number of bits to identify a color
* bits [I] Pointer to array containing color data
*
* RETURNS
* Success: Handle to bitmap
* Failure: 0
*/
HBITMAP WINAPI CreateBitmap( INT width, INT height, UINT planes,
UINT bpp, LPCVOID bits )
{
BITMAP bm;
bm.bmType = 0;
bm.bmWidth = width;
bm.bmHeight = height;
bm.bmWidthBytes = BITMAP_GetWidthBytes( width, bpp );
bm.bmPlanes = planes;
bm.bmBitsPixel = bpp;
bm.bmBits = (LPVOID)bits;
return CreateBitmapIndirect( &bm );
}
/******************************************************************************
* CreateCompatibleBitmap [GDI32.@]
*
* Creates a bitmap compatible with the DC.
*
* PARAMS
* hdc [I] Handle to device context
* width [I] Width of bitmap
* height [I] Height of bitmap
*
* RETURNS
* Success: Handle to bitmap
* Failure: 0
*/
HBITMAP WINAPI CreateCompatibleBitmap( HDC hdc, INT width, INT height)
{
HBITMAP hbmpRet = 0;
TRACE("(%p,%d,%d) =\n", hdc, width, height);
if (GetObjectType( hdc ) != OBJ_MEMDC)
{
hbmpRet = CreateBitmap(width, height,
GetDeviceCaps(hdc, PLANES),
GetDeviceCaps(hdc, BITSPIXEL),
NULL);
}
else /* Memory DC */
{
DIBSECTION dib;
HBITMAP bitmap = GetCurrentObject( hdc, OBJ_BITMAP );
INT size = GetObjectW( bitmap, sizeof(dib), &dib );
if (!size) return 0;
if (size == sizeof(BITMAP))
{
/* A device-dependent bitmap is selected in the DC */
hbmpRet = CreateBitmap(width, height,
dib.dsBm.bmPlanes,
dib.dsBm.bmBitsPixel,
NULL);
}
else
{
/* A DIB section is selected in the DC */
BITMAPINFO *bi;
void *bits;
/* Allocate memory for a BITMAPINFOHEADER structure and a
color table. The maximum number of colors in a color table
is 256 which corresponds to a bitmap with depth 8.
Bitmaps with higher depths don't have color tables. */
bi = HeapAlloc(GetProcessHeap(), 0, sizeof(BITMAPINFOHEADER) + 256 * sizeof(RGBQUAD));
if (bi)
{
bi->bmiHeader.biSize = sizeof(bi->bmiHeader);
bi->bmiHeader.biWidth = width;
bi->bmiHeader.biHeight = height;
bi->bmiHeader.biPlanes = dib.dsBmih.biPlanes;
bi->bmiHeader.biBitCount = dib.dsBmih.biBitCount;
bi->bmiHeader.biCompression = dib.dsBmih.biCompression;
bi->bmiHeader.biSizeImage = 0;
bi->bmiHeader.biXPelsPerMeter = dib.dsBmih.biXPelsPerMeter;
bi->bmiHeader.biYPelsPerMeter = dib.dsBmih.biYPelsPerMeter;
bi->bmiHeader.biClrUsed = dib.dsBmih.biClrUsed;
bi->bmiHeader.biClrImportant = dib.dsBmih.biClrImportant;
if (bi->bmiHeader.biCompression == BI_BITFIELDS)
{
/* Copy the color masks */
CopyMemory(bi->bmiColors, dib.dsBitfields, 3 * sizeof(DWORD));
}
else if (bi->bmiHeader.biBitCount <= 8)
{
/* Copy the color table */
GetDIBColorTable(hdc, 0, 256, bi->bmiColors);
}
hbmpRet = CreateDIBSection(hdc, bi, DIB_RGB_COLORS, &bits, NULL, 0);
HeapFree(GetProcessHeap(), 0, bi);
}
}
}
TRACE("\t\t%p\n", hbmpRet);
return hbmpRet;
}
/******************************************************************************
* CreateBitmapIndirect [GDI32.@]
*
* Creates a bitmap with the specified info.
*
* PARAMS
* bmp [I] Pointer to the bitmap info describing the bitmap
*
* RETURNS
* Success: Handle to bitmap
* Failure: NULL. Use GetLastError() to determine the cause.
*
* NOTES
* If a width or height of 0 are given, a 1x1 monochrome bitmap is returned.
*/
HBITMAP WINAPI CreateBitmapIndirect( const BITMAP *bmp )
{
BITMAP bm;
BITMAPOBJ *bmpobj;
HBITMAP hbitmap;
if (!bmp || bmp->bmType)
{
SetLastError( ERROR_INVALID_PARAMETER );
return NULL;
}
if (bmp->bmWidth > 0x7ffffff || bmp->bmHeight > 0x7ffffff)
{
SetLastError( ERROR_INVALID_PARAMETER );
return 0;
}
bm = *bmp;
if (!bm.bmWidth || !bm.bmHeight)
{
return GetStockObject( DEFAULT_BITMAP );
}
else
{
if (bm.bmHeight < 0)
bm.bmHeight = -bm.bmHeight;
if (bm.bmWidth < 0)
bm.bmWidth = -bm.bmWidth;
}
if (bm.bmPlanes != 1)
{
FIXME("planes = %d\n", bm.bmPlanes);
SetLastError( ERROR_INVALID_PARAMETER );
return NULL;
}
/* Windows only uses 1, 4, 8, 16, 24 and 32 bpp */
if(bm.bmBitsPixel == 1) bm.bmBitsPixel = 1;
else if(bm.bmBitsPixel <= 4) bm.bmBitsPixel = 4;
else if(bm.bmBitsPixel <= 8) bm.bmBitsPixel = 8;
else if(bm.bmBitsPixel <= 16) bm.bmBitsPixel = 16;
else if(bm.bmBitsPixel <= 24) bm.bmBitsPixel = 24;
else if(bm.bmBitsPixel <= 32) bm.bmBitsPixel = 32;
else {
WARN("Invalid bmBitsPixel %d, returning ERROR_INVALID_PARAMETER\n", bm.bmBitsPixel);
SetLastError(ERROR_INVALID_PARAMETER);
return NULL;
}
/* Windows ignores the provided bm.bmWidthBytes */
bm.bmWidthBytes = BITMAP_GetWidthBytes( bm.bmWidth, bm.bmBitsPixel );
/* XP doesn't allow to create bitmaps larger than 128 Mb */
if (bm.bmHeight > 128 * 1024 * 1024 / bm.bmWidthBytes)
{
SetLastError( ERROR_NOT_ENOUGH_MEMORY );
return 0;
}
/* Create the BITMAPOBJ */
if (!(bmpobj = HeapAlloc( GetProcessHeap(), 0, sizeof(*bmpobj) )))
{
SetLastError( ERROR_NOT_ENOUGH_MEMORY );
return 0;
}
bmpobj->size.cx = 0;
bmpobj->size.cy = 0;
bmpobj->bitmap = bm;
bmpobj->bitmap.bmBits = NULL;
bmpobj->funcs = NULL;
bmpobj->dib = NULL;
bmpobj->color_table = NULL;
bmpobj->nb_colors = 0;
if (!(hbitmap = alloc_gdi_handle( &bmpobj->header, OBJ_BITMAP, &bitmap_funcs )))
{
HeapFree( GetProcessHeap(), 0, bmpobj );
return 0;
}
if (bm.bmBits)
SetBitmapBits( hbitmap, bm.bmHeight * bm.bmWidthBytes, bm.bmBits );
TRACE("%dx%d, %d colors returning %p\n", bm.bmWidth, bm.bmHeight,
1 << (bm.bmPlanes * bm.bmBitsPixel), hbitmap);
return hbitmap;
}
/***********************************************************************
* GetBitmapBits [GDI32.@]
*
* Copies bitmap bits of bitmap to buffer.
*
* RETURNS
* Success: Number of bytes copied
* Failure: 0
*/
LONG WINAPI GetBitmapBits(
HBITMAP hbitmap, /* [in] Handle to bitmap */
LONG count, /* [in] Number of bytes to copy */
LPVOID bits) /* [out] Pointer to buffer to receive bits */
{
BITMAPOBJ *bmp = GDI_GetObjPtr( hbitmap, OBJ_BITMAP );
LONG height, ret;
if (!bmp) return 0;
if (bmp->dib) /* simply copy the bits from the DIB */
{
DIBSECTION *dib = bmp->dib;
const char *src = dib->dsBm.bmBits;
INT width_bytes = BITMAP_GetWidthBytes(dib->dsBm.bmWidth, dib->dsBm.bmBitsPixel);
LONG max = width_bytes * bmp->bitmap.bmHeight;
if (!bits)
{
ret = max;
goto done;
}
if (count > max) count = max;
ret = count;
/* GetBitmapBits returns not 32-bit aligned data */
if (bmp->dib->dsBmih.biHeight >= 0) /* not top-down, need to flip contents vertically */
{
src += dib->dsBm.bmWidthBytes * dib->dsBm.bmHeight;
while (count > 0)
{
src -= dib->dsBm.bmWidthBytes;
memcpy( bits, src, min( count, width_bytes ) );
bits = (char *)bits + width_bytes;
count -= width_bytes;
}
}
else
{
while (count > 0)
{
memcpy( bits, src, min( count, width_bytes ) );
src += dib->dsBm.bmWidthBytes;
bits = (char *)bits + width_bytes;
count -= width_bytes;
}
}
goto done;
}
/* If the bits vector is null, the function should return the read size */
if(bits == NULL)
{
ret = bmp->bitmap.bmWidthBytes * bmp->bitmap.bmHeight;
goto done;
}
if (count < 0) {
WARN("(%d): Negative number of bytes passed???\n", count );
count = -count;
}
/* Only get entire lines */
height = count / bmp->bitmap.bmWidthBytes;
if (height > bmp->bitmap.bmHeight) height = bmp->bitmap.bmHeight;
count = height * bmp->bitmap.bmWidthBytes;
if (count == 0)
{
WARN("Less than one entire line requested\n");
ret = 0;
goto done;
}
TRACE("(%p, %d, %p) %dx%d %d colors fetched height: %d\n",
hbitmap, count, bits, bmp->bitmap.bmWidth, bmp->bitmap.bmHeight,
1 << bmp->bitmap.bmBitsPixel, height );
if(bmp->funcs && bmp->funcs->pGetBitmapBits)
{
TRACE("Calling device specific BitmapBits\n");
ret = bmp->funcs->pGetBitmapBits(hbitmap, bits, count);
} else {
if(!bmp->bitmap.bmBits) {
TRACE("Bitmap is empty\n");
memset(bits, 0, count);
ret = count;
} else {
memcpy(bits, bmp->bitmap.bmBits, count);
ret = count;
}
}
done:
GDI_ReleaseObj( hbitmap );
return ret;
}
/******************************************************************************
* SetBitmapBits [GDI32.@]
*
* Sets bits of color data for a bitmap.
*
* RETURNS
* Success: Number of bytes used in setting the bitmap bits
* Failure: 0
*/
LONG WINAPI SetBitmapBits(
HBITMAP hbitmap, /* [in] Handle to bitmap */
LONG count, /* [in] Number of bytes in bitmap array */
LPCVOID bits) /* [in] Address of array with bitmap bits */
{
BITMAPOBJ *bmp;
LONG height, ret;
if (!bits) return 0;
bmp = GDI_GetObjPtr( hbitmap, OBJ_BITMAP );
if (!bmp) return 0;
if (count < 0) {
WARN("(%d): Negative number of bytes passed???\n", count );
count = -count;
}
if (bmp->dib) /* simply copy the bits into the DIB */
{
DIBSECTION *dib = bmp->dib;
char *dest = dib->dsBm.bmBits;
LONG max = dib->dsBm.bmWidthBytes * dib->dsBm.bmHeight;
if (count > max) count = max;
ret = count;
if (bmp->dib->dsBmih.biHeight >= 0) /* not top-down, need to flip contents vertically */
{
dest += dib->dsBm.bmWidthBytes * dib->dsBm.bmHeight;
while (count > 0)
{
dest -= dib->dsBm.bmWidthBytes;
memcpy( dest, bits, min( count, dib->dsBm.bmWidthBytes ) );
bits = (const char *)bits + dib->dsBm.bmWidthBytes;
count -= dib->dsBm.bmWidthBytes;
}
}
else memcpy( dest, bits, count );
GDI_ReleaseObj( hbitmap );
return ret;
}
/* Only get entire lines */
height = count / bmp->bitmap.bmWidthBytes;
if (height > bmp->bitmap.bmHeight) height = bmp->bitmap.bmHeight;
count = height * bmp->bitmap.bmWidthBytes;
TRACE("(%p, %d, %p) %dx%d %d colors fetched height: %d\n",
hbitmap, count, bits, bmp->bitmap.bmWidth, bmp->bitmap.bmHeight,
1 << bmp->bitmap.bmBitsPixel, height );
if(bmp->funcs && bmp->funcs->pSetBitmapBits) {
TRACE("Calling device specific BitmapBits\n");
ret = bmp->funcs->pSetBitmapBits(hbitmap, bits, count);
} else {
if(!bmp->bitmap.bmBits) /* Alloc enough for entire bitmap */
bmp->bitmap.bmBits = HeapAlloc( GetProcessHeap(), 0, count );
if(!bmp->bitmap.bmBits) {
WARN("Unable to allocate bit buffer\n");
ret = 0;
} else {
memcpy(bmp->bitmap.bmBits, bits, count);
ret = count;
}
}
GDI_ReleaseObj( hbitmap );
return ret;
}
/**********************************************************************
* BITMAP_CopyBitmap
*
*/
HBITMAP BITMAP_CopyBitmap(HBITMAP hbitmap)
{
HBITMAP res;
DIBSECTION dib;
DWORD size;
if (!(size = GetObjectW( hbitmap, sizeof(dib), &dib ))) return 0;
if (size == sizeof(DIBSECTION))
{
void *bits;
BITMAPINFO *bi;
HDC dc = CreateCompatibleDC( NULL );
if (!dc) return 0;
if (!(bi = HeapAlloc(GetProcessHeap(), 0, FIELD_OFFSET( BITMAPINFO, bmiColors[256] ))))
{
DeleteDC( dc );
return 0;
}
bi->bmiHeader = dib.dsBmih;
/* Get the color table or the color masks */
GetDIBits( dc, hbitmap, 0, 0, NULL, bi, DIB_RGB_COLORS );
res = CreateDIBSection( dc, bi, DIB_RGB_COLORS, &bits, NULL, 0 );
if (res) SetDIBits( dc, res, 0, dib.dsBm.bmHeight, dib.dsBm.bmBits, bi, DIB_RGB_COLORS );
HeapFree( GetProcessHeap(), 0, bi );
DeleteDC( dc );
return res;
}
res = CreateBitmapIndirect( &dib.dsBm );
if(res) {
char *buf = HeapAlloc( GetProcessHeap(), 0, dib.dsBm.bmWidthBytes * dib.dsBm.bmHeight );
GetBitmapBits (hbitmap, dib.dsBm.bmWidthBytes * dib.dsBm.bmHeight, buf);
SetBitmapBits (res, dib.dsBm.bmWidthBytes * dib.dsBm.bmHeight, buf);
HeapFree( GetProcessHeap(), 0, buf );
}
return res;
}
/***********************************************************************
* BITMAP_SetOwnerDC
*
* Set the type of DC that owns the bitmap. This is used when the
* bitmap is selected into a device to initialize the bitmap function
* table.
*/
BOOL BITMAP_SetOwnerDC( HBITMAP hbitmap, DC *dc )
{
BITMAPOBJ *bitmap;
BOOL ret;
/* never set the owner of the stock bitmap since it can be selected in multiple DCs */
if (hbitmap == GetStockObject(DEFAULT_BITMAP)) return TRUE;
if (!(bitmap = GDI_GetObjPtr( hbitmap, OBJ_BITMAP ))) return FALSE;
ret = TRUE;
if (!bitmap->funcs) /* not owned by a DC yet */
{
if (dc->funcs->pCreateBitmap) ret = dc->funcs->pCreateBitmap( dc->physDev, hbitmap,
bitmap->bitmap.bmBits );
if (ret) bitmap->funcs = dc->funcs;
}
else if (bitmap->funcs != dc->funcs)
{
FIXME( "Trying to select bitmap %p in different DC type\n", hbitmap );
ret = FALSE;
}
GDI_ReleaseObj( hbitmap );
return ret;
}
/***********************************************************************
* BITMAP_SelectObject
*/
static HGDIOBJ BITMAP_SelectObject( HGDIOBJ handle, HDC hdc )
{
HGDIOBJ ret;
BITMAPOBJ *bitmap;
DC *dc;
if (!(dc = get_dc_ptr( hdc ))) return 0;
if (GetObjectType( hdc ) != OBJ_MEMDC)
{
ret = 0;
goto done;
}
ret = dc->hBitmap;
if (handle == dc->hBitmap) goto done; /* nothing to do */
if (!(bitmap = GDI_GetObjPtr( handle, OBJ_BITMAP )))
{
ret = 0;
goto done;
}
if (bitmap->header.selcount && (handle != GetStockObject(DEFAULT_BITMAP)))
{
WARN( "Bitmap already selected in another DC\n" );
GDI_ReleaseObj( handle );
ret = 0;
goto done;
}
if (!bitmap->funcs && !BITMAP_SetOwnerDC( handle, dc ))
{
GDI_ReleaseObj( handle );
ret = 0;
goto done;
}
if (dc->funcs->pSelectBitmap && !dc->funcs->pSelectBitmap( dc->physDev, handle ))
{
GDI_ReleaseObj( handle );
ret = 0;
}
else
{
dc->hBitmap = handle;
GDI_inc_ref_count( handle );
dc->dirty = 0;
dc->vis_rect.left = 0;
dc->vis_rect.top = 0;
dc->vis_rect.right = bitmap->bitmap.bmWidth;
dc->vis_rect.bottom = bitmap->bitmap.bmHeight;
SetRectRgn( dc->hVisRgn, 0, 0, bitmap->bitmap.bmWidth, bitmap->bitmap.bmHeight);
GDI_ReleaseObj( handle );
DC_InitDC( dc );
GDI_dec_ref_count( ret );
}
done:
release_dc_ptr( dc );
return ret;
}
/***********************************************************************
* BITMAP_DeleteObject
*/
static BOOL BITMAP_DeleteObject( HGDIOBJ handle )
{
const DC_FUNCTIONS *funcs;
BITMAPOBJ *bmp = GDI_GetObjPtr( handle, OBJ_BITMAP );
if (!bmp) return FALSE;
funcs = bmp->funcs;
GDI_ReleaseObj( handle );
if (funcs && funcs->pDeleteBitmap) funcs->pDeleteBitmap( handle );
if (!(bmp = free_gdi_handle( handle ))) return FALSE;
HeapFree( GetProcessHeap(), 0, bmp->bitmap.bmBits );
if (bmp->dib)
{
DIBSECTION *dib = bmp->dib;
if (dib->dsBm.bmBits)
{
if (dib->dshSection)
{
SYSTEM_INFO SystemInfo;
GetSystemInfo( &SystemInfo );
UnmapViewOfFile( (char *)dib->dsBm.bmBits -
(dib->dsOffset % SystemInfo.dwAllocationGranularity) );
}
else if (!dib->dsOffset)
VirtualFree(dib->dsBm.bmBits, 0L, MEM_RELEASE );
}
HeapFree(GetProcessHeap(), 0, dib);
HeapFree(GetProcessHeap(), 0, bmp->color_table);
}
return HeapFree( GetProcessHeap(), 0, bmp );
}
/***********************************************************************
* BITMAP_GetObject
*/
static INT BITMAP_GetObject( HGDIOBJ handle, INT count, LPVOID buffer )
{
INT ret;
BITMAPOBJ *bmp = GDI_GetObjPtr( handle, OBJ_BITMAP );
if (!bmp) return 0;
if (!buffer) ret = sizeof(BITMAP);
else if (count < sizeof(BITMAP)) ret = 0;
else if (bmp->dib)
{
if (count >= sizeof(DIBSECTION))
{
DIBSECTION *dib = buffer;
*dib = *bmp->dib;
dib->dsBmih.biHeight = abs( dib->dsBmih.biHeight );
ret = sizeof(DIBSECTION);
}
else /* if (count >= sizeof(BITMAP)) */
{
DIBSECTION *dib = bmp->dib;
memcpy( buffer, &dib->dsBm, sizeof(BITMAP) );
ret = sizeof(BITMAP);
}
}
else
{
memcpy( buffer, &bmp->bitmap, sizeof(BITMAP) );
((BITMAP *) buffer)->bmBits = NULL;
ret = sizeof(BITMAP);
}
GDI_ReleaseObj( handle );
return ret;
}
/******************************************************************************
* CreateDiscardableBitmap [GDI32.@]
*
* Creates a discardable bitmap.
*
* RETURNS
* Success: Handle to bitmap
* Failure: NULL
*/
HBITMAP WINAPI CreateDiscardableBitmap(
HDC hdc, /* [in] Handle to device context */
INT width, /* [in] Bitmap width */
INT height) /* [in] Bitmap height */
{
return CreateCompatibleBitmap( hdc, width, height );
}
/******************************************************************************
* GetBitmapDimensionEx [GDI32.@]
*
* Retrieves dimensions of a bitmap.
*
* RETURNS
* Success: TRUE
* Failure: FALSE
*/
BOOL WINAPI GetBitmapDimensionEx(
HBITMAP hbitmap, /* [in] Handle to bitmap */
LPSIZE size) /* [out] Address of struct receiving dimensions */
{
BITMAPOBJ * bmp = GDI_GetObjPtr( hbitmap, OBJ_BITMAP );
if (!bmp) return FALSE;
*size = bmp->size;
GDI_ReleaseObj( hbitmap );
return TRUE;
}
/******************************************************************************
* SetBitmapDimensionEx [GDI32.@]
*
* Assigns dimensions to a bitmap.
* MSDN says that this function will fail if hbitmap is a handle created by
* CreateDIBSection, but that's not true on Windows 2000.
*
* RETURNS
* Success: TRUE
* Failure: FALSE
*/
BOOL WINAPI SetBitmapDimensionEx(
HBITMAP hbitmap, /* [in] Handle to bitmap */
INT x, /* [in] Bitmap width */
INT y, /* [in] Bitmap height */
LPSIZE prevSize) /* [out] Address of structure for orig dims */
{
BITMAPOBJ * bmp = GDI_GetObjPtr( hbitmap, OBJ_BITMAP );
if (!bmp) return FALSE;
if (prevSize) *prevSize = bmp->size;
bmp->size.cx = x;
bmp->size.cy = y;
GDI_ReleaseObj( hbitmap );
return TRUE;
}