Sweden-Number/dlls/gdi32/bitmap.c

710 lines
21 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 */
};
/***********************************************************************
* null driver fallback implementations
*/
DWORD nulldrv_GetImage( PHYSDEV dev, HBITMAP hbitmap, BITMAPINFO *info,
struct gdi_image_bits *bits, struct bitblt_coords *src )
{
if (!hbitmap) return ERROR_NOT_SUPPORTED;
return dib_driver.pGetImage( 0, hbitmap, info, bits, src );
}
DWORD nulldrv_PutImage( PHYSDEV dev, HBITMAP hbitmap, HRGN clip, BITMAPINFO *info,
const struct gdi_image_bits *bits, struct bitblt_coords *src,
struct bitblt_coords *dst, DWORD rop )
{
if (!hbitmap) return ERROR_SUCCESS;
return dib_driver.pPutImage( NULL, hbitmap, clip, info, bits, src, dst, rop );
}
BOOL nulldrv_CopyBitmap( HBITMAP src, HBITMAP dst )
{
BOOL ret = TRUE;
BITMAPOBJ *src_bmp = GDI_GetObjPtr( src, OBJ_BITMAP );
if (!src_bmp) return FALSE;
if (src_bmp->dib.dsBm.bmBits)
{
BITMAPOBJ *dst_bmp = GDI_GetObjPtr( dst, OBJ_BITMAP );
int stride = get_dib_stride( dst_bmp->dib.dsBm.bmWidth, dst_bmp->dib.dsBm.bmBitsPixel );
dst_bmp->dib.dsBm.bmBits = HeapAlloc( GetProcessHeap(), 0, dst_bmp->dib.dsBm.bmHeight * stride );
if (dst_bmp->dib.dsBm.bmBits)
memcpy( dst_bmp->dib.dsBm.bmBits, src_bmp->dib.dsBm.bmBits, dst_bmp->dib.dsBm.bmHeight * stride );
else
ret = FALSE;
GDI_ReleaseObj( dst );
}
GDI_ReleaseObj( src );
return ret;
}
/******************************************************************************
* 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 = get_bitmap_stride( 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)
{
char buffer[FIELD_OFFSET( BITMAPINFO, bmiColors[256] )];
BITMAPINFO *bi = (BITMAPINFO *)buffer;
DIBSECTION dib;
TRACE("(%p,%d,%d)\n", hdc, width, height);
if (GetObjectType( hdc ) != OBJ_MEMDC)
return CreateBitmap( width, height,
GetDeviceCaps(hdc, PLANES), GetDeviceCaps(hdc, BITSPIXEL), NULL );
switch (GetObjectW( GetCurrentObject( hdc, OBJ_BITMAP ), sizeof(dib), &dib ))
{
case sizeof(BITMAP): /* A device-dependent bitmap is selected in the DC */
return CreateBitmap( width, height, dib.dsBm.bmPlanes, dib.dsBm.bmBitsPixel, NULL );
case sizeof(DIBSECTION): /* A DIB section is selected in the DC */
bi->bmiHeader = dib.dsBmih;
bi->bmiHeader.biWidth = width;
bi->bmiHeader.biHeight = height;
if (dib.dsBmih.biCompression == BI_BITFIELDS) /* copy the color masks */
memcpy(bi->bmiColors, dib.dsBitfields, sizeof(dib.dsBitfields));
else if (dib.dsBmih.biBitCount <= 8) /* copy the color table */
GetDIBColorTable(hdc, 0, 256, bi->bmiColors);
return CreateDIBSection( hdc, bi, DIB_RGB_COLORS, NULL, NULL, 0 );
default:
return 0;
}
}
/******************************************************************************
* 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 = get_bitmap_stride( 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(), HEAP_ZERO_MEMORY, sizeof(*bmpobj) )))
{
SetLastError( ERROR_NOT_ENOUGH_MEMORY );
return 0;
}
bmpobj->dib.dsBm = bm;
bmpobj->dib.dsBm.bmBits = NULL;
bmpobj->funcs = &null_driver;
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, bpp %d planes %d: returning %p\n", bm.bmWidth, bm.bmHeight,
bm.bmBitsPixel, bm.bmPlanes, 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 */
{
char buffer[FIELD_OFFSET( BITMAPINFO, bmiColors[256] )];
BITMAPINFO *info = (BITMAPINFO *)buffer;
struct gdi_image_bits src_bits;
struct bitblt_coords src;
int dst_stride, max, ret;
BITMAPOBJ *bmp = GDI_GetObjPtr( hbitmap, OBJ_BITMAP );
if (!bmp) return 0;
dst_stride = get_bitmap_stride( bmp->dib.dsBm.bmWidth, bmp->dib.dsBm.bmBitsPixel );
ret = max = dst_stride * bmp->dib.dsBm.bmHeight;
if (!bits) goto done;
if (count > max) count = max;
ret = count;
src.visrect.left = 0;
src.visrect.right = bmp->dib.dsBm.bmWidth;
src.visrect.top = 0;
src.visrect.bottom = (count + dst_stride - 1) / dst_stride;
src.x = src.y = 0;
src.width = src.visrect.right - src.visrect.left;
src.height = src.visrect.bottom - src.visrect.top;
if (!bmp->funcs->pGetImage( NULL, hbitmap, info, &src_bits, &src ))
{
const char *src_ptr = src_bits.ptr;
int src_stride = get_dib_stride( info->bmiHeader.biWidth, info->bmiHeader.biBitCount );
/* GetBitmapBits returns 16-bit aligned data */
if (info->bmiHeader.biHeight > 0)
{
src_ptr += (info->bmiHeader.biHeight - 1) * src_stride;
src_stride = -src_stride;
}
src_ptr += src.visrect.top * src_stride;
if (src_stride == dst_stride) memcpy( bits, src_ptr, count );
else while (count > 0)
{
memcpy( bits, src_ptr, min( count, dst_stride ) );
src_ptr += src_stride;
bits = (char *)bits + dst_stride;
count -= dst_stride;
}
if (src_bits.free) src_bits.free( &src_bits );
}
else ret = 0;
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 */
{
char buffer[FIELD_OFFSET( BITMAPINFO, bmiColors[256] )];
BITMAPINFO *info = (BITMAPINFO *)buffer;
BITMAPOBJ *bmp;
DWORD err;
int i, src_stride, dst_stride;
struct bitblt_coords src, dst;
struct gdi_image_bits src_bits;
HRGN clip = NULL;
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;
}
src_stride = get_bitmap_stride( bmp->dib.dsBm.bmWidth, bmp->dib.dsBm.bmBitsPixel );
count = min( count, src_stride * bmp->dib.dsBm.bmHeight );
dst_stride = get_dib_stride( bmp->dib.dsBm.bmWidth, bmp->dib.dsBm.bmBitsPixel );
src.visrect.left = src.x = 0;
src.visrect.top = src.y = 0;
src.visrect.right = src.width = bmp->dib.dsBm.bmWidth;
src.visrect.bottom = src.height = (count + src_stride - 1 ) / src_stride;
dst = src;
if (count % src_stride)
{
HRGN last_row;
int extra_pixels = ((count % src_stride) << 3) / bmp->dib.dsBm.bmBitsPixel;
if ((count % src_stride << 3) % bmp->dib.dsBm.bmBitsPixel)
FIXME( "Unhandled partial pixel\n" );
clip = CreateRectRgn( src.visrect.left, src.visrect.top,
src.visrect.right, src.visrect.bottom - 1 );
last_row = CreateRectRgn( src.visrect.left, src.visrect.bottom - 1,
src.visrect.left + extra_pixels, src.visrect.bottom );
CombineRgn( clip, clip, last_row, RGN_OR );
DeleteObject( last_row );
}
TRACE("(%p, %d, %p) %dx%d %d bpp fetched height: %d\n",
hbitmap, count, bits, bmp->dib.dsBm.bmWidth, bmp->dib.dsBm.bmHeight,
bmp->dib.dsBm.bmBitsPixel, src.height );
if (src_stride == dst_stride)
{
src_bits.ptr = (void *)bits;
src_bits.is_copy = FALSE;
src_bits.free = NULL;
}
else
{
if (!(src_bits.ptr = HeapAlloc( GetProcessHeap(), 0, dst.height * dst_stride )))
{
GDI_ReleaseObj( hbitmap );
return 0;
}
src_bits.is_copy = TRUE;
src_bits.free = free_heap_bits;
for (i = 0; i < count / src_stride; i++)
memcpy( (char *)src_bits.ptr + i * dst_stride, (char *)bits + i * src_stride, src_stride );
if (count % src_stride)
memcpy( (char *)src_bits.ptr + i * dst_stride, (char *)bits + i * src_stride, count % src_stride );
}
/* query the color info */
info->bmiHeader.biSize = sizeof(info->bmiHeader);
info->bmiHeader.biPlanes = 1;
info->bmiHeader.biBitCount = bmp->dib.dsBm.bmBitsPixel;
info->bmiHeader.biCompression = BI_RGB;
info->bmiHeader.biXPelsPerMeter = 0;
info->bmiHeader.biYPelsPerMeter = 0;
info->bmiHeader.biClrUsed = 0;
info->bmiHeader.biClrImportant = 0;
info->bmiHeader.biWidth = 0;
info->bmiHeader.biHeight = 0;
info->bmiHeader.biSizeImage = 0;
err = bmp->funcs->pPutImage( NULL, hbitmap, 0, info, NULL, NULL, NULL, SRCCOPY );
if (!err || err == ERROR_BAD_FORMAT)
{
info->bmiHeader.biWidth = bmp->dib.dsBm.bmWidth;
info->bmiHeader.biHeight = -dst.height;
info->bmiHeader.biSizeImage = dst.height * dst_stride;
err = bmp->funcs->pPutImage( NULL, hbitmap, clip, info, &src_bits, &src, &dst, SRCCOPY );
}
if (err) count = 0;
if (clip) DeleteObject( clip );
if (src_bits.free) src_bits.free( &src_bits );
GDI_ReleaseObj( hbitmap );
return count;
}
static void set_initial_bitmap_bits( HBITMAP hbitmap, BITMAPOBJ *bmp )
{
char src_bmibuf[FIELD_OFFSET( BITMAPINFO, bmiColors[256] )];
BITMAPINFO *src_info = (BITMAPINFO *)src_bmibuf;
char dst_bmibuf[FIELD_OFFSET( BITMAPINFO, bmiColors[256] )];
BITMAPINFO *dst_info = (BITMAPINFO *)dst_bmibuf;
DWORD err;
struct gdi_image_bits bits;
struct bitblt_coords src, dst;
if (!bmp->dib.dsBm.bmBits) return;
if (bmp->funcs->pPutImage == nulldrv_PutImage) return;
get_ddb_bitmapinfo( bmp, src_info );
bits.ptr = bmp->dib.dsBm.bmBits;
bits.is_copy = FALSE;
bits.free = NULL;
bits.param = NULL;
src.x = 0;
src.y = 0;
src.width = bmp->dib.dsBm.bmWidth;
src.height = bmp->dib.dsBm.bmHeight;
src.visrect.left = 0;
src.visrect.top = 0;
src.visrect.right = bmp->dib.dsBm.bmWidth;
src.visrect.bottom = bmp->dib.dsBm.bmHeight;
dst = src;
copy_bitmapinfo( dst_info, src_info );
err = bmp->funcs->pPutImage( NULL, hbitmap, 0, dst_info, &bits, &src, &dst, 0 );
if (err == ERROR_BAD_FORMAT)
{
err = convert_bits( src_info, &src, dst_info, &bits, FALSE );
if (!err) err = bmp->funcs->pPutImage( NULL, hbitmap, 0, dst_info, &bits, &src, &dst, 0 );
if (bits.free) bits.free( &bits );
}
}
/***********************************************************************
* BITMAP_SelectObject
*/
static HGDIOBJ BITMAP_SelectObject( HGDIOBJ handle, HDC hdc )
{
HGDIOBJ ret;
BITMAPOBJ *bitmap;
DC *dc;
PHYSDEV physdev = NULL, old_physdev = NULL, createdev;
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 (dc->dibdrv) old_physdev = pop_dc_driver( dc, dc->dibdrv );
physdev = GET_DC_PHYSDEV( dc, pSelectBitmap );
createdev = GET_DC_PHYSDEV( dc, pCreateBitmap );
if (physdev->funcs == &null_driver)
{
physdev = dc->dibdrv;
if (physdev) push_dc_driver( &dc->physDev, physdev, physdev->funcs );
else
{
if (!dib_driver.pCreateDC( &dc->physDev, NULL, NULL, NULL, NULL )) goto done;
dc->dibdrv = physdev = dc->physDev;
}
}
/* never set the owner of the stock bitmap since it can be selected in multiple DCs */
if (handle != GetStockObject(DEFAULT_BITMAP) && bitmap->funcs != createdev->funcs)
{
/* we can only change from the null driver to some other driver */
if (bitmap->funcs != &null_driver)
{
FIXME( "Trying to select bitmap %p in different DC type\n", handle );
GDI_ReleaseObj( handle );
ret = 0;
goto done;
}
if (createdev->funcs != &null_driver)
{
if (!createdev->funcs->pCreateBitmap( createdev, handle ))
{
GDI_ReleaseObj( handle );
ret = 0;
goto done;
}
bitmap->funcs = createdev->funcs;
set_initial_bitmap_bits( handle, bitmap );
}
else bitmap->funcs = &dib_driver; /* use the DIB driver to emulate DDB support */
}
if (!physdev->funcs->pSelectBitmap( 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->dib.dsBm.bmWidth;
dc->vis_rect.bottom = bitmap->dib.dsBm.bmHeight;
dc->device_rect = dc->vis_rect;
GDI_ReleaseObj( handle );
DC_InitDC( dc );
GDI_dec_ref_count( ret );
}
done:
if(!ret)
{
if (physdev && physdev == dc->dibdrv) pop_dc_driver( dc, dc->dibdrv );
if (old_physdev) push_dc_driver( &dc->physDev, old_physdev, old_physdev->funcs );
}
release_dc_ptr( dc );
return ret;
}
/***********************************************************************
* BITMAP_DeleteObject
*/
static BOOL BITMAP_DeleteObject( HGDIOBJ handle )
{
const struct gdi_dc_funcs *funcs;
BITMAPOBJ *bmp = GDI_GetObjPtr( handle, OBJ_BITMAP );
if (!bmp) return FALSE;
funcs = bmp->funcs;
GDI_ReleaseObj( handle );
funcs->pDeleteBitmap( handle );
if (!(bmp = free_gdi_handle( handle ))) return FALSE;
HeapFree( GetProcessHeap(), 0, bmp->dib.dsBm.bmBits );
return HeapFree( GetProcessHeap(), 0, bmp );
}
/***********************************************************************
* BITMAP_GetObject
*/
static INT BITMAP_GetObject( HGDIOBJ handle, INT count, LPVOID buffer )
{
INT ret = 0;
BITMAPOBJ *bmp = GDI_GetObjPtr( handle, OBJ_BITMAP );
if (!bmp) return 0;
if (!buffer) ret = sizeof(BITMAP);
else if (count >= sizeof(BITMAP))
{
BITMAP *bitmap = buffer;
*bitmap = bmp->dib.dsBm;
bitmap->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;
}