C / C++ / MFC

EliottA wrote:

Also, a general question, why use pointers (*) if you can use Addresses (&) to reference objects?

EliottA wrote:

What exactly are the following datatypes

1. Handle
2. PVOID
3. DWORD

EliottA wrote:

Also, a general question, why use pointers (*) if you can use Addresses (&) to reference objects?

negativeG wrote:

I want to make that instance be get focus and be the top most application.

negativeG wrote:

Sure, but how do I find the hWnd for the Applet (it is a dialog based) from my App?

negativeG wrote:

I want to make that instance be get focus and be the top most application.

alexhalt wrote:

But at this line


(void)jpeg_write_scanlines( &cinfo,
jsmpArray,
cinfo.image_height );




I've got the following error
Improper call to jpeg library in state 100

Stuart Dootson wrote:

If you're using Visual Studio 2003 or later, it might be easier to use CImage[^], as that has built-in 'save as jpeg' functionality?

Stuart Dootson wrote:

Looking at the code for libjpeg, 100 is the 'initialisation' state. This error would be raised by jpeg_write_scanlines if you hadn't called jpeg_start_compress.

bRet = OpenClipboard( hwndWindow );
	
	// ERROR_SUCCESS
	


	uFormat = CountClipboardFormats();
	
	
	hClipboardData = GetClipboardData( CF_BITMAP );


	hDib = DDBToDIB( ( HBITMAP )hClipboardData, BI_RGB, NULL );
	lpbi = ( LPBITMAPINFOHEADER )hDib;

	
		
	{
		struct jpeg_compress_struct cinfo;
		struct jpeg_error_mgr jerr;
		FILE * outfile;
		char filename[] = "out.jpg";

		cinfo.err = jpeg_std_error(&jerr);
		jpeg_create_compress(&cinfo);


		
		//! destination
		if ((outfile = fopen(filename, "wb")) == NULL) {
			fprintf(stderr, "can't open %s\n", filename);
			exit(1);
		}
		jpeg_stdio_dest(&cinfo, outfile);


		cinfo.image_width = lpbi->biWidth; 	/* image width and height, in pixels */
		cinfo.image_height = lpbi->biHeight;
		
		cinfo.input_components = 3;// lpbi->biBitCount/8;	/* # of color components per pixel */
		
		cinfo.in_color_space = JCS_RGB; /* colorspace of input image */

		jpeg_set_defaults(&cinfo);
		
		
		/* Make optional parameter settings here */
		{
			
			JSAMPARRAY jsmpArray;    //Pixel RGB buffer for JPEG file
			
			
			
			jsmpArray = (*cinfo.mem->alloc_sarray)
                ((j_common_ptr) &cinfo,
                 JPOOL_IMAGE,
                 cinfo.image_width * cinfo.input_components,
                 cinfo.image_height);

			
			DibToSamps(	hDib, cinfo.image_width * cinfo.input_components, cinfo, jsmpArray );

			jpeg_start_compress(&cinfo,TRUE);


			(void)jpeg_write_scanlines( &cinfo,
                                       jsmpArray,
                                       cinfo.image_height );

HANDLE DDBToDIB( HBITMAP bitmap, DWORD dwCompression, HPALETTE pPal ) 
{
	BITMAP			bm;
	BITMAPINFOHEADER	bi;
	LPBITMAPINFOHEADER 	lpbi;
	DWORD			dwLen;
	HANDLE			hDIB;
	HANDLE			handle;
	HDC 			hDC;
	HPALETTE		hPal;
	int nColors = 0;
	BOOL bGotBits;


	// The function has no arg for bitfields
	if( dwCompression == BI_BITFIELDS )
		return NULL;

	// If a palette has not been supplied use defaul palette
	hPal = (HPALETTE) pPal;
	if (hPal==NULL)
		hPal = (HPALETTE) GetStockObject(DEFAULT_PALETTE);

	// Get bitmap information
	GetObject(bitmap,sizeof(bm),(LPSTR)&bm);

	// Initialize the bitmapinfoheader
	bi.biSize		= sizeof(BITMAPINFOHEADER);
	bi.biWidth		= bm.bmWidth;
	bi.biHeight 		= bm.bmHeight;
	bi.biPlanes 		= 1;
	bi.biBitCount		= bm.bmPlanes * bm.bmBitsPixel;
	bi.biCompression	= dwCompression;
	bi.biSizeImage		= 0;
	bi.biXPelsPerMeter	= 0;
	bi.biYPelsPerMeter	= 0;
	bi.biClrUsed		= 0;
	bi.biClrImportant	= 0;

	// Compute the size of the  infoheader and the color table
	nColors = (1 << bi.biBitCount);
	if( nColors > 256 ) 
		nColors = 0;
	dwLen  = bi.biSize + nColors * sizeof(RGBQUAD);

	// We need a device context to get the DIB from
	hDC = GetDC(NULL);
	hPal = SelectPalette(hDC,hPal,FALSE);
	RealizePalette(hDC);

	// Allocate enough memory to hold bitmapinfoheader and color table
	hDIB = GlobalAlloc(GMEM_FIXED,dwLen);

	if (!hDIB)
	{
		SelectPalette(hDC,hPal,FALSE);
		ReleaseDC(NULL,hDC);
		return NULL;
	}

	lpbi = (LPBITMAPINFOHEADER)hDIB;

	*lpbi = bi;

	// Call GetDIBits with a NULL lpBits param, so the device driver 
	// will calculate the biSizeImage field 
	GetDIBits(hDC, (HBITMAP)bitmap, 0L, (DWORD)bi.biHeight,
			(LPBYTE)NULL, (LPBITMAPINFO)lpbi, (DWORD)DIB_RGB_COLORS);

	bi = *lpbi;

	// If the driver did not fill in the biSizeImage field, then compute it
	// Each scan line of the image is aligned on a DWORD (32bit) boundary
	if (bi.biSizeImage == 0)
	{
		bi.biSizeImage = ((((bi.biWidth * bi.biBitCount) + 31) & ~31) / 8) 
						* bi.biHeight;

		// If a compression scheme is used the result may infact be larger
		// Increase the size to account for this.
		if (dwCompression != BI_RGB)
			bi.biSizeImage = (bi.biSizeImage * 3) / 2;
	}

	// Realloc the buffer so that it can hold all the bits
	dwLen += bi.biSizeImage;
	if (handle = GlobalReAlloc(hDIB, dwLen, GMEM_MOVEABLE))
	{
		hDIB = handle;
	}
	else
	{
		GlobalFree(hDIB);
		
		// Reselect the original palette
		SelectPalette(hDC,hPal,FALSE);
		ReleaseDC(NULL,hDC);
		return NULL;
	}
	
	// Get the bitmap bits
	lpbi = (LPBITMAPINFOHEADER)hDIB;
	
	// FINALLY get the DIB
	bGotBits = GetDIBits( hDC, bitmap,
		0L,				// Start scan line
		(DWORD)bi.biHeight,		// # of scan lines
		(LPBYTE)lpbi 			// address for bitmap bits
		+ (bi.biSize + nColors * sizeof(RGBQUAD)),
		(LPBITMAPINFO)lpbi,		// address of bitmapinfo
		(DWORD)DIB_RGB_COLORS);		// Use RGB for color table
	
	if( !bGotBits )
	{
		GlobalFree(hDIB);
		
		SelectPalette(hDC,hPal,FALSE);
		ReleaseDC(NULL,hDC);
		return NULL;
	}
	
	SelectPalette(hDC,hPal,FALSE);
	ReleaseDC(NULL,hDC);
	return hDIB;
}

(void)jpeg_write_scanlines( &cinfo,
                                       jsmpArray,
                                       cinfo.image_height );

FISH786 wrote:

fopen_s

FISH786 wrote:

My question is short of going through the headear files, can someone recommend a good book or has a good documentation or a link that he/she is willing to share for the different functions.