【转帖】how to save the preview bitmap
 

how to save the preview bitmap
how to save the preview bitmap
in the toolkit age, i can use follow codes to get the preview bitmap file:
"
cstring pvbmppath = "c:\\data\\preview.bmp";
int bmpflag = adextractbmpfromfiletofile(lpstr(lpszfilename),(lp str)(lpcstr)pvbmppath);
"
now i use dwgdirect to do the same thing.
i get the bitmapinfo* info, but i can not save it to a bitmap file.
" oduint32 datalength = 0;
bitmapinfo* info = (bitmapinfo*)m_pdb->thumbnailbitmap(datalength);
void* pbits = null;
hbitmap hbitmap = createdibsection( null, info , dib_rgb_colors , &pbits, null, 0 );
writebitmaptofile( hbitmap, lpszfilename );
"
have anyone do the same thing? i need your help.
last edited by jiff; 28th july 2005 at 09:27 pmfff">.
it's my writebitmaptofile() function.
i use follow funtion to save the picture file , but it's useless, just get a black bitmap.
bool writebitmaptofile( hbitmap hbitmap, lpcstr lpszfilename )
{
assert( lpszfilename != null );
if (hbitmap == null)
return false;
dibsection ds;
::getobject( hbitmap, sizeof(ds), &ds );
int ncolors = (1 << ds.dsbmih.bibitcount);
if (ncolors > 256) // can not support more than 256 color
return false;
if (ds.dsbmih.bisizeimage == 0)
{
ds.dsbmih.bisizeimage = ((((ds.dsbmih.biwidth * ds.dsbmih.bibitcount) + 31) & ~31) / 8)
* ds.dsbmih.biheight;
}
// get color data
rgbquad* prgb = (rgbquad*)malloc( sizeof(rgbquad)*ncolors );
cclientdc dc( null );
cdc memdc;
memdc.createcompatibledc(&dc);
hbitmap hold = (hbitmap)memdc.selectobject( hbitmap );
uint nentry = ::getdibcolortable( memdc, 0, ncolors, prgb );
verify( nentry == (uint)ncolors );
memdc.selectobject( hold );
memdc.deletedc();
// bitmap file header
bitmapfileheader hdr;
hdr.bftype = ((word) ('m' << 8) | 'b'); // is always "bm"
hdr.bfsize = sizeof(bitmapinfoheader) + sizeof(rgbquad)*ncolors + sizeof( hdr ) +
ds.dsbmih.bisizeimage;
hdr.bfreserved1 = 0;
hdr.bfreserved2 = 0;
hdr.bfoffbits = sizeof( hdr ) + sizeof(bitmapinfoheader) + sizeof(rgbquad)*ncolors;
try
{
cfile file;
if( !file.open( lpszfilename, cfile::modewrite|cfile::modecreate) )
return false;
file.write( &hdr, sizeof( hdr ) );
file.write( &ds.dsbmih, sizeof( ds.dsbmih ) );
file.write( prgb, sizeof(rgbquad)*ncolors );
file.write( ds.dsbm.bmbits, ds.dsbmih.bisizeimage );
}
catch ( cfileexception, e )
{
return false;
}
end_catch
free( prgb );
return true;
}
i got it too!!
i read wjs "extract thumbnail to file", then i change his codes a little. thanks wjs. i can save my bitmap file now. :-)
last edited by jiff; 29th july 2005 at 01:23 amfff">.