C Win32: save .bmp image from HBITMAP - c

Question

I am working with a framegrabber and need to get the images from computer memory and save them on an image file. after trying for couple of days I end up with the following 2 functions, which creates a file and windows OS is able to run the .bmp file, but the bitmap file is black (the image size is 900KB , 640*480). does any body has any idea why, the picture is in black?
here are the two functions :
LPSTR CreateBMP( HWND hAppWnd, int nImageType )
{
void * pWinGBits = NULL;
int i;
Z_BITMAPINFO zWinGHeader; // bitmapinfo for cerating the DIB
// create DC for bitmap.
hDCBits = CreateCompatibleDC( ghDCMain );
switch ( nImageType )
{
case bayer_filter:
zWinGHeader.bmiHeader.biSize = sizeof( BITMAPINFOHEADER );
zWinGHeader.bmiHeader.biPlanes = 1;
zWinGHeader.bmiHeader.biClrImportant = 0;
zWinGHeader.bmiHeader.biHeight = -lYSize;
zWinGHeader.bmiHeader.biWidth = lXSize;
zWinGHeader.bmiHeader.biBitCount = 32;
zWinGHeader.bmiHeader.biClrUsed = 0;//3;
zWinGHeader.bmiHeader.biCompression = BI_BITFIELDS;
zWinGHeader.bmiHeader.biSizeImage = 0;
zWinGHeader.bmiColors[0].rgbBlue = 0x00;
zWinGHeader.bmiColors[0].rgbGreen = 0x00;
zWinGHeader.bmiColors[0].rgbRed = 0xFF;
zWinGHeader.bmiColors[0].rgbReserved = 0x00;
zWinGHeader.bmiColors[1].rgbBlue = 0x00;
zWinGHeader.bmiColors[1].rgbGreen = 0xFF;
zWinGHeader.bmiColors[1].rgbRed = 0x00;
zWinGHeader.bmiColors[1].rgbReserved = 0x00;
zWinGHeader.bmiColors[2].rgbBlue = 0xFF;
zWinGHeader.bmiColors[2].rgbGreen = 0x00;
zWinGHeader.bmiColors[2].rgbRed = 0x00;
zWinGHeader.bmiColors[2].rgbReserved = 0x00;
break;
case color32:
zWinGHeader.bmiHeader.biSize = sizeof( BITMAPINFOHEADER );
zWinGHeader.bmiHeader.biPlanes = 1;
zWinGHeader.bmiHeader.biClrImportant = 0;
zWinGHeader.bmiHeader.biHeight = -lYSize;
zWinGHeader.bmiHeader.biWidth = lXSize/4;
zWinGHeader.bmiHeader.biBitCount = 32;
zWinGHeader.bmiHeader.biClrUsed = 0;
zWinGHeader.bmiHeader.biCompression = BI_BITFIELDS;
zWinGHeader.bmiHeader.biSizeImage = 0;
zWinGHeader.bmiColors[0].rgbBlue = 0x00;
zWinGHeader.bmiColors[0].rgbGreen = 0x00;
zWinGHeader.bmiColors[0].rgbRed = 0xFF;
zWinGHeader.bmiColors[0].rgbReserved = 0x00;
zWinGHeader.bmiColors[1].rgbBlue = 0x00;
zWinGHeader.bmiColors[1].rgbGreen = 0xFF;
zWinGHeader.bmiColors[1].rgbRed = 0x00;
zWinGHeader.bmiColors[1].rgbReserved = 0x00;
zWinGHeader.bmiColors[2].rgbBlue = 0xFF;
zWinGHeader.bmiColors[2].rgbGreen = 0x00;
zWinGHeader.bmiColors[2].rgbRed = 0x00;
zWinGHeader.bmiColors[2].rgbReserved = 0x00;
break;
case color24:
zWinGHeader.bmiHeader.biSize = sizeof( BITMAPINFOHEADER );
zWinGHeader.bmiHeader.biPlanes = 1;
zWinGHeader.bmiHeader.biClrImportant = 0;
zWinGHeader.bmiHeader.biHeight = -lYSize;
zWinGHeader.bmiHeader.biWidth = lXSize/3;
zWinGHeader.bmiHeader.biBitCount = 24;
zWinGHeader.bmiHeader.biClrUsed = 0;
zWinGHeader.bmiHeader.biCompression = BI_RGB;
zWinGHeader.bmiHeader.biSizeImage = 0;
break;
case color3x16:
zWinGHeader.bmiHeader.biSize = sizeof( BITMAPINFOHEADER );
zWinGHeader.bmiHeader.biPlanes = 1;
zWinGHeader.bmiHeader.biClrImportant = 0;
zWinGHeader.bmiHeader.biHeight = -lYSize;
zWinGHeader.bmiHeader.biWidth = lXSize/6;
zWinGHeader.bmiHeader.biBitCount = 32;
zWinGHeader.bmiHeader.biClrUsed = 0;
zWinGHeader.bmiHeader.biCompression = BI_BITFIELDS;
zWinGHeader.bmiHeader.biSizeImage = 0;
zWinGHeader.bmiColors[0].rgbBlue = 0x00;
zWinGHeader.bmiColors[0].rgbGreen = 0x00;
zWinGHeader.bmiColors[0].rgbRed = 0xFF;
zWinGHeader.bmiColors[0].rgbReserved = 0x00;
zWinGHeader.bmiColors[1].rgbBlue = 0x00;
zWinGHeader.bmiColors[1].rgbGreen = 0xFF;
zWinGHeader.bmiColors[1].rgbRed = 0x00;
zWinGHeader.bmiColors[1].rgbReserved = 0x00;
zWinGHeader.bmiColors[2].rgbBlue = 0xFF;
zWinGHeader.bmiColors[2].rgbGreen = 0x00;
zWinGHeader.bmiColors[2].rgbRed = 0x00;
zWinGHeader.bmiColors[2].rgbReserved = 0x00;
break;
case bw1x10:
// create bitmap-infoheader.
zWinGHeader.bmiHeader.biSize = sizeof( BITMAPINFOHEADER );
zWinGHeader.bmiHeader.biPlanes = 1;
zWinGHeader.bmiHeader.biBitCount = 8;
zWinGHeader.bmiHeader.biCompression = BI_RGB;
zWinGHeader.bmiHeader.biSizeImage = 0;
zWinGHeader.bmiHeader.biClrUsed = 256;
zWinGHeader.bmiHeader.biClrImportant= 0;
zWinGHeader.bmiHeader.biHeight = -lYSize;
zWinGHeader.bmiHeader.biWidth = lXSize/2;
// create colortable fot bitmap (grayvalues).
for (i = 0; i < 256; i++)
{
zWinGHeader.bmiColors[i].rgbGreen = i;
zWinGHeader.bmiColors[i].rgbBlue = i;
zWinGHeader.bmiColors[i].rgbRed = i;
zWinGHeader.bmiColors[i].rgbReserved = 0;
}
break;
default:
case bw8:
// create bitmap-infoheader.
zWinGHeader.bmiHeader.biSize = sizeof( BITMAPINFOHEADER );
zWinGHeader.bmiHeader.biPlanes = 1;
zWinGHeader.bmiHeader.biBitCount = 8;
zWinGHeader.bmiHeader.biCompression = BI_RGB;
zWinGHeader.bmiHeader.biSizeImage = 0;
zWinGHeader.bmiHeader.biClrUsed = (1<<8);
zWinGHeader.bmiHeader.biClrImportant= 0;
zWinGHeader.bmiHeader.biHeight = -lYSize;
zWinGHeader.bmiHeader.biWidth = lXSize;
//zWinGHeader.bmiHeader.biSizeImage = ((zWinGHeader.bmiHeader.biWidth * 8 +31) & ~31) /8
// * zWinGHeader.bmiHeader.biHeight;
// create colortable fot bitmap (grayvalues).
for (i = 0; i < 256; i++)
{
zWinGHeader.bmiColors[i].rgbGreen = i;
zWinGHeader.bmiColors[i].rgbBlue = i;
zWinGHeader.bmiColors[i].rgbRed = i;
zWinGHeader.bmiColors[i].rgbReserved = 0;
}
break;
}
// cerate identity palette
hPal = CreateIdentityPalette( zWinGHeader.bmiColors );
// get new palette into DC and map into physical palette register.
hOldPal = SelectPalette( ghDCMain, hPal, FALSE);
RealizePalette( ghDCMain );
// cerate DIB-Section f黵 direct access of image-data.
hBitmap = CreateDIBSection(
hDCBits, // handle of device context
(BITMAPINFO *)&zWinGHeader, // address of structure containing
// bitmap size, format and color data
DIB_RGB_COLORS, // color data type indicator: RGB values
// or palette indices
&pWinGBits, // pointer to variable to receive a pointer
// to the bitmap's bit values
NULL, // optional handle to a file mapping object
0 // offset to the bitmap bit values within
// the file mapping object
);
// get bitmap into DC .
hOldBitmap = (HBITMAP)SelectObject( hDCBits, hBitmap );
return pWinGBits; // return pointer to DIB
}
and here is the function for saving into .bmp :
BOOL SaveToFile(HBITMAP hBitmap3, LPCTSTR lpszFileName)
{
HDC hDC;
int iBits;
WORD wBitCount;
DWORD dwPaletteSize=0, dwBmBitsSize=0, dwDIBSize=0, dwWritten=0;
BITMAP Bitmap0;
BITMAPFILEHEADER bmfHdr;
BITMAPINFOHEADER bi;
LPBITMAPINFOHEADER lpbi;
HANDLE fh, hDib, hPal,hOldPal2=NULL;
hDC = CreateDC("DISPLAY", NULL, NULL, NULL);
iBits = GetDeviceCaps(hDC, BITSPIXEL) * GetDeviceCaps(hDC, PLANES);
DeleteDC(hDC);
if (iBits <= 1)
wBitCount = 1;
else if (iBits <= 4)
wBitCount = 4;
else if (iBits <= 8)
wBitCount = 8;
else
wBitCount = 24;
GetObject(hBitmap3, sizeof(Bitmap0), (LPSTR)&Bitmap0);
bi.biSize = sizeof(BITMAPINFOHEADER);
bi.biWidth = Bitmap0.bmWidth;
bi.biHeight =-Bitmap0.bmHeight;
bi.biPlanes = 1;
bi.biBitCount = wBitCount;
bi.biCompression = BI_RGB;
bi.biSizeImage = 0;
bi.biXPelsPerMeter = 0;
bi.biYPelsPerMeter = 0;
bi.biClrImportant = 0;
bi.biClrUsed = 256;
dwBmBitsSize = ((Bitmap0.bmWidth * wBitCount +31) & ~31) /8
* Bitmap0.bmHeight;
hDib = GlobalAlloc(GHND,dwBmBitsSize + dwPaletteSize + sizeof(BITMAPINFOHEADER));
lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib);
*lpbi = bi;
hPal = GetStockObject(DEFAULT_PALETTE);
if (hPal)
{
hDC = GetDC(NULL);
hOldPal2 = SelectPalette(hDC, (HPALETTE)hPal, FALSE);
RealizePalette(hDC);
}
GetDIBits(hDC, hBitmap3, 0, (UINT) Bitmap0.bmHeight, (LPSTR)lpbi + sizeof(BITMAPINFOHEADER)
+dwPaletteSize, (BITMAPINFO *)lpbi, DIB_RGB_COLORS);
if (hOldPal2)
{
SelectPalette(hDC, (HPALETTE)hOldPal2, TRUE);
RealizePalette(hDC);
ReleaseDC(NULL, hDC);
}
fh = CreateFile(lpszFileName, GENERIC_WRITE,0, NULL, CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL);
if (fh == INVALID_HANDLE_VALUE)
return FALSE;
bmfHdr.bfType = 0x4D42; // "BM"
dwDIBSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + dwPaletteSize + dwBmBitsSize;
bmfHdr.bfSize = dwDIBSize;
bmfHdr.bfReserved1 = 0;
bmfHdr.bfReserved2 = 0;
bmfHdr.bfOffBits = (DWORD)sizeof(BITMAPFILEHEADER) + (DWORD)sizeof(BITMAPINFOHEADER) + dwPaletteSize;
WriteFile(fh, (LPSTR)&bmfHdr, sizeof(BITMAPFILEHEADER), &dwWritten, NULL);
WriteFile(fh, (LPSTR)lpbi, dwDIBSize, &dwWritten, NULL);
GlobalUnlock(hDib);
GlobalFree(hDib);
CloseHandle(fh);
counter=1;
return TRUE;
}
I CAN Draw the images from memory perfectly with the following function, so for sure I dont have any problem for reading the image data :
void DrawPicture( HDC hDC, PBYTE pDest, PBYTE pSrc, LONG lXSize, LONG lYSize )
{
LONG lXSizeDiv, lYSizeDiv;
LONG lX, lY;
DWORD dwMax;
RECT rect;
HDC hdc;
PBYTE pTmpDest;
double fXFactor, fYFactor;
// HBRUSH hBrush;
// POINT Point;
switch( gzMvfgKamDef.iImageType )
{
case bayer_filter:
lXSizeDiv = 1;
lYSizeDiv = 1;
BayerToRGB( (PDWORD) pDest, pSrc, lXSize, lYSize,
gzMvfgKamDef.iBayerQuadrant, gzMvfgKamDef.iBayerQuality );
break;
case color24:
lXSizeDiv = 3;
lYSizeDiv = 1;
memcpy( pDest, pSrc, (size_t)( lXSize * lYSize ) );
break;
case color32:
lXSizeDiv = 4;
lYSizeDiv = 1;
memcpy( pDest, pSrc, (size_t)( lXSize * lYSize ) );
break;
case color3x16:
lXSizeDiv = 6;
lYSizeDiv = 1;
Conv3x16To3x8( pDest, pSrc, 4, lXSize, lYSize );
break;
case bw1x10:
lXSizeDiv = 2;
lYSizeDiv = 1;
Conv1x10To1x8( pDest, pSrc, 2, lXSize, lYSize );
break;
case bw6Tap:
lXSizeDiv = 1;
lYSizeDiv = 1;
Conv6TapTo1x8( pDest, pSrc, 1, lXSize, lYSize );
break;
default:
case bw8:
lXSizeDiv = 1;
lYSizeDiv = 1;
memcpy( pDest, pSrc, (size_t)( lXSize * lYSize ) );
break;
}
if( gahIniDlg[ NdxHistogramDlg ].hWnd )
{
memset( gadwHistogram, 0, sizeof( gadwHistogram) );
pTmpDest = pDest;
for ( lY = 0; lY < lYSize; lY++ )
{
for ( lX = 0; lX < lXSize; lX++ )
{
gadwHistogram[ *pTmpDest ]++;
pTmpDest++;
}
}
GetClientRect ( gahIniDlg[ NdxHistogramDlg ].hWnd, &rect) ;
hdc = GetDC ( gahIniDlg[ NdxHistogramDlg ].hWnd );
dwMax = 0;
for ( lX = 0 ; lX <= 0xff; lX++ )
dwMax = ( gadwHistogram[ lX ] > dwMax ) ? gadwHistogram[ lX ] : dwMax;
fYFactor = (double) dwMax / (double) rect.bottom;
fXFactor = (double) ( rect.right - 100 ) / (double) 0x100;
/*
SelectObject (hdc, GetStockObject (BLACK_PEN)) ;
for( lX = 0; lX <= 0xff; lX+=8 )
{
MoveToEx( hdc, lX * fXFactor, rect.bottom, &Point );
LineTo( hdc, lX * fXFactor, rect.bottom-10 );
}
*/
SelectObject (hdc, GetStockObject (WHITE_PEN)) ;
// hBrush = CreateSolidBrush( GetSysColor( COLOR_WINDOW ));
// hBrush = CreateSolidBrush( 0xffffff );
// SelectObject (hdc, hBrush);
Polyline( hdc, gaHistogram, 0x100 );
// DeleteObject( hBrush );
for ( lX = 0 ; lX <= 0xff; lX++ )
{
gaHistogram[ lX ].x = (DWORD)( fXFactor * (double)lX );
gaHistogram[ lX ].y = rect.bottom - (DWORD)( (double) gadwHistogram[ lX ] / fYFactor );
}
SelectObject (hdc, GetStockObject (BLACK_PEN)) ;
Polyline( hdc, gaHistogram, 0x100 );
ReleaseDC ( gahIniDlg[ NdxHistogramDlg ].hWnd , hdc ) ;
}
// display the bitmap
StretchBlt( hDC, rcWin.left, rcWin.top, lXSize / lXSizeDiv, lYSize / lYSizeDiv,
hDCBits, 0, 0, lXSize / lXSizeDiv, lYSize / lYSizeDiv, SRCCOPY );
//BitBlt( hDC, rcWin.left, rcWin.top, lXSize / lXSizeDiv, lYSize / lYSizeDiv,
//hDCBits, 0, 0, SRCCOPY );
}

Answer 1

I just find out I had a silly mistake in another part of my code I was using :
// Convert Image to bitmap and display it
DrawPicture( ghDCMain, pWinGBitmap, gpbImageData, lXSize, lYSize );
if(counter!=1) {
hBitmap2 = CreateCompatibleBitmap (hDCBits, lXSize, lYSize);
SaveToFile(hBitmap2, "c:\\t.bmp");
OutputDebugString("tested !!!!");
}
by deleting the hBitmap2 = CreateCompatibleBitmap (hDCBits, lXSize, lYSize); line, and changing the hBitmap2 to hBitmap the result of CreateDIBSection(), it saved the image beautifully. THANK YOU EVERYONE FOR YOUR HELP.

Answer 2

FORMAT_INFO sFormat;
mvfg_getparam( MVFGPAR_DATAFORMAT, &sFormat, giCurrentGrabberID);
long lFrameSize = sFormat.lFrameSize;
BYTE *pBitmap = (BYTE*)malloc(FrameSize);
memcpy( pBitmap, CamGetPicture(), FrameSize );
writeBitmapToFile(pBitmap, FrameSize, "tmp.bmp");
/*
* write our raw data into a bitmap file
* adding the correct header and put it all
* together in a single file
*/
int
writeBitmapToFile(void *data, unsigned long size, const char *filename)
{
bmpFileHeader_t header;
bmpInfoHeader_t info;
bmpRGBQuad_t rgb = { 0, 0, 0, 0};
FILE *out;
size_t len;
int i;
header.type = 0x4d42; // magic sequence 'BM'
header.size = 0;
header.res0 = 0;
header.res1 = 0;
/* 256 different colors, each is defined by an bmpRBQuad type */
header.offset = 256 * sizeof(bmpRGBQuad_t) +
sizeof(bmpInfoHeader_t) + sizeof(bmpFileHeader_t);
info.size = sizeof(bmpInfoHeader_t);
info.width = WIDTH;
info.height = HEIGHT;
info.planes = 1;
info.cDepth = 8; /* 8 Bit */
info.compression = 0;
info.rawSize = size;
info.hRes = 0;
info.vRes = 0;
info.nrColors = 0x100;
info.impColors = 0;
out = fopen(filename, "wb");
if (out == NULL) {
printf("error cannot open %s for writing\n", filename);
return -1;
}
len = fwrite(&header, 1, sizeof(header), out);
if (len != sizeof(header)) {
printf("error while writing header\n");
return -1;
}
len = fwrite(&info, 1, sizeof(info), out);
if (len != sizeof(info)) {
printf("error while writing info header\n");
return -1;
}
/* stupid try and error programming leads to this */
for (i = 0; i < 256; i++) {
rgb.red = i;
rgb.green = i;
rgb.blue = i;
len = fwrite(&rgb, 1, sizeof(rgb), out);
if (len != sizeof(rgb)) {
printf("error while writing rgb header\n");
return -1;
}
}
len = fwrite(data, 1, size, out);
if (len != size ) {
printf("error while writing bitmap data\n");
return -1;
}
return 0;
}
Reference - mikrotron
Reference - write bitmap

Answer 3

Are you sure there is proper data in there?
I would try extract the RGB data and save it in some very simple format "manually", just to see what is in there. If you are looking for a dead simple but still standard image format, look at PPM images.

Answer 4

From the documentation for CreateCompatibleDC:
When the memory DC is created, its display surface is exactly one monochrome pixel wide and one monochrome pixel high. Before an application can use a memory DC for drawing operations, it must select a bitmap of the correct width and height into the DC.
Since you're using CreateDIBSection with that DC, the resulting DIB section will be 1-bit monochrome as well.