dibapi.cpp

用于网络传输时的Jpg和Bmp格式相互转换的API封装

WORD DIBBitCount(LPBYTE lpDIB) 
{ 
    if (IS_WIN30_DIB(lpDIB)) 
        return ((LPBITMAPINFOHEADER)lpDIB)->biBitCount; 
    else 
        return ((LPBITMAPCOREHEADER)lpDIB)->bcBitCount; 
} 

WORD DIBBitCount(HDIB hDIB) 
{ 
	LPBYTE lpDIB = (LPBYTE)GlobalLock(hDIB);
	WORD wSize = DIBBitCount(lpDIB);
	GlobalUnlock(hDIB);
	return wSize;
} 
 
/**************************************************************************** 
* 
*     FUNCTION: BytesPerLine 
* 
*     PURPOSE:  Calculates the number of bytes in one scan line. 
* 
*     PARAMS:   LPBYTE lpDIB - pointer to the BITMAPINFOHEADER 
                              that begins the CF_DIB block 
* 
*     RETURNS:  DWORD - number of bytes in one scan line (DWORD aligned) 
* 
\****************************************************************************/ 
DWORD BytesPerLine(LPBYTE lpDIB) 
{ 
    return WIDTHBYTES(((LPBITMAPINFOHEADER)lpDIB)->biWidth * ((LPBITMAPINFOHEADER)lpDIB)->biPlanes * ((LPBITMAPINFOHEADER)lpDIB)->biBitCount); 
} 

DWORD BytesPerLine(HDIB hDIB) 
{ 
	LPBYTE lpDIB = (LPBYTE)GlobalLock(hDIB);
	DWORD dw = BytesPerLine(lpDIB);
	GlobalUnlock(hDIB);
	return dw;
} 

/**************************************************************************** 
* 
*     FUNCTION: DIBlockSize 
* 
*     PURPOSE:  Calculates the number of bytes in one scan line. 
* 
*     PARAMS:   LPBYTE lpDIB - pointer to the BITMAPINFOHEADER 
                              that begins the CF_DIB block 
* 
*     RETURNS:  DWORD - DIB block size
* 
\****************************************************************************/ 
DWORD DIBlockSize(LPBYTE lpDIB)
{
	if (((LPBITMAPINFOHEADER)lpDIB)->biSizeImage == 0)
		((LPBITMAPINFOHEADER)lpDIB)->biSizeImage = BytesPerLine(lpDIB) * ((LPBITMAPINFOHEADER)lpDIB)->biHeight;
	return ((LPBITMAPINFOHEADER)lpDIB)->biSize + PaletteSize(lpDIB) + ((LPBITMAPINFOHEADER)lpDIB)->biSizeImage;
}

DWORD DIBlockSize(HDIB hDIB) 
{ 
	LPBYTE lpDIB = (LPBYTE)GlobalLock(hDIB);
	DWORD dw = DIBlockSize(lpDIB);
	GlobalUnlock(hDIB);
	return dw;
} 
 
/************************************************************************* 
 * 
 * CreateDIBPalette() 
 * 
 * Parameter: 
 * 
 * LPBYTE lpbi       - specifies the DIB 
 * 
 * Return Value: 
 * 
 * HPALETTE         - specifies the palette 
 * 
 * Description: 
 * 
 * This function creates a palette from a DIB by allocating memory for the 
 * logical palette, reading and storing the colors from the DIB's color table 
 * into the logical palette, creating a palette from this logical palette, 
 * and then returning the palette's handle. This allows the DIB to be 
 * displayed using the best possible colors (important for DIBs with 256 or 
 * more colors). 
 * 
 ************************************************************************/ 
HPALETTE CreateDIBPalette(LPBYTE lpbi) 
{ 
    LPLOGPALETTE        lpPal;          // pointer to a logical palette 
    HANDLE              hLogPal;        // handle to a logical palette 
    HPALETTE            hPal = NULL;    // handle to a palette 
    int                 i, wNumColors;  // loop index, number of colors in color table 
    LPBITMAPINFO        lpbmi;          // pointer to BITMAPINFO structure (Win3.0) 
    LPBITMAPCOREINFO    lpbmc;          // pointer to BITMAPCOREINFO structure (OS/2) 
    BOOL                bWinStyleDIB;   // Win3.0 DIB? 
 
    // if handle to DIB is invalid, return NULL 
 
    if (! lpbi) 
        return NULL; 
 
    // get pointer to BITMAPINFO (Win 3.0) 
 
    lpbmi = (LPBITMAPINFO)lpbi; 
 
    // get pointer to BITMAPCOREINFO (OS/2 1.x) 
 
    lpbmc = (LPBITMAPCOREINFO)lpbi; 
 
    // get the number of colors in the DIB  
 
    wNumColors = DIBNumColors(lpbi); 
 
    // is this a Win 3.0 DIB? 
 
    bWinStyleDIB = IS_WIN30_DIB(lpbi); 
    if (wNumColors) 
    { 
        // allocate memory block for logical palette 
 
        hLogPal = GlobalAlloc(GHND, sizeof(LOGPALETTE) + 
                sizeof(PALETTEENTRY) * wNumColors); 
 
        // if not enough memory, clean up and return NULL 
 
        if (!hLogPal) 
            return NULL; 
 
        // lock memory block and get pointer to it 
 
        lpPal = (LPLOGPALETTE)GlobalLock(hLogPal); 
 
        // set version and number of palette entries 
 
        lpPal->palVersion = PALVERSION; 
        lpPal->palNumEntries = wNumColors; 
 
        // store RGB triples (if Win 3.0 DIB) or RGB quads (if OS/2 DIB) 
        // into palette 
         
        for (i = 0; i < wNumColors; i++) 
        { 
            if (bWinStyleDIB) 
            { 
                lpPal->palPalEntry[i].peRed = lpbmi->bmiColors[i].rgbRed; 
                lpPal->palPalEntry[i].peGreen = lpbmi->bmiColors[i].rgbGreen; 
                lpPal->palPalEntry[i].peBlue = lpbmi->bmiColors[i].rgbBlue; 
                lpPal->palPalEntry[i].peFlags = 0; 
            } 
            else 
            { 
                lpPal->palPalEntry[i].peRed = lpbmc->bmciColors[i].rgbtRed; 
                lpPal->palPalEntry[i].peGreen = lpbmc->bmciColors[i].rgbtGreen; 
                lpPal->palPalEntry[i].peBlue = lpbmc->bmciColors[i].rgbtBlue; 
                lpPal->palPalEntry[i].peFlags = 0; 
            } 
        } 
 
        // create the palette and get handle to it 
 
        hPal = CreatePalette(lpPal); 
 
        // cleanup
 
        GlobalUnlock(hLogPal); 
        GlobalFree(hLogPal); 
    } 
 
    // return handle to DIB's palette 
    return hPal; 
} 
 
/************************************************************************* 
 * 
 * CreateDIBPalette() 
 * 
 * Parameter: 
 * 
 * HDIB hDIB        - specifies the DIB 
 * 
 * Return Value: 
 * 
 * HPALETTE         - specifies the palette 
 * 
 * Description: 
 * 
 * This function creates a palette from a DIB by allocating memory for the 
 * logical palette, reading and storing the colors from the DIB's color table 
 * into the logical palette, creating a palette from this logical palette, 
 * and then returning the palette's handle. This allows the DIB to be 
 * displayed using the best possible colors (important for DIBs with 256 or 
 * more colors). 
 * 
 ************************************************************************/ 
HPALETTE CreateDIBPalette(HDIB hDIB) 
{ 
    HPALETTE            hPal = NULL;    // handle to a palette 
    LPBYTE               lpbi;           // pointer to packed-DIB 
 
    // if handle to DIB is invalid, return NULL 
 
    if (!hDIB) 
        return NULL; 
 
    // lock DIB memory block and get a pointer to it 
 
    lpbi = (LPBYTE)GlobalLock(hDIB); 
 
	hPal = CreateDIBPalette(lpbi);

	// Unlock hDIB
    GlobalUnlock(hDIB); 
 
    // return handle to DIB's palette 
    return hPal; 
} 
 
/************************************************************************* 
 * 
 * DIBToBitmap() 
 * 
 * Parameters: 
 * 
 * HDIB hDIB        - specifies the DIB to convert 
 * 
 * HPALETTE hPal    - specifies the palette to use with the bitmap 
 * 
 * Return Value: 
 * 
 * HBITMAP          - identifies the device-dependent bitmap 
 * 
 * Description: 
 * 
 * This function creates a bitmap from a DIB using the specified palette. 
 * If no palette is specified, default is used. 
 * 
 * NOTE: 
 * 
 * The bitmap returned from this funciton is always a bitmap compatible 
 * with the screen (e.g. same bits/pixel and color planes) rather than 
 * a bitmap with the same attributes as the DIB.  This behavior is by 
 * design, and occurs because this function calls CreateDIBitmap to 
 * do its work, and CreateDIBitmap always creates a bitmap compatible 
 * with the hDC parameter passed in (because it in turn calls 
 * CreateCompatibleBitmap). 
 * 
 * So for instance, if your DIB is a monochrome DIB and you call this 
 * function, you will not get back a monochrome HBITMAP -- you will 
 * get an HBITMAP compatible with the screen DC, but with only 2 
 * colors used in the bitmap. 
 * 
 * If your application requires a monochrome HBITMAP returned for a 
 * monochrome DIB, use the function SetDIBits(). 
 * 
 * Also, the DIBpassed in to the function is not destroyed on exit. This 
 * must be done later, once it is no longer needed. 
 * 
 ************************************************************************/ 
HBITMAP DIBToBitmap(HDIB hDIB, HPALETTE hPal) 
{ 
    LPBYTE       lpDIBHdr, lpDIBBits;  // pointer to DIB header, pointer to DIB bits 
    HBITMAP     hBitmap;            // handle to device-dependent bitmap 
    HDC         hDC;                    // handle to DC 
    HPALETTE    hOldPal = NULL;    // handle to a palette 
 
    // if invalid handle, return NULL  
 
    if (!hDIB) 
        return NULL; 
 
    // lock memory block and get a pointer to it 
 
    lpDIBHdr = (LPBYTE)GlobalLock(hDIB); 
 
    // get a pointer to the DIB bits 
 
    lpDIBBits = FindDIBBits(lpDIBHdr); 
 
    // get a DC  
 
    hDC = GetDC(NULL); 
    if (!hDC) 
    { 
        // clean up and return NULL 
        GlobalUnlock(hDIB); 
        return NULL; 
    } 
 
    // select and realize palette 
 
    if (hPal) 
	{
        hOldPal = SelectPalette(hDC, hPal, FALSE); 
	    RealizePalette(hDC); 
	}
 
    // create bitmap from DIB info and bits 
    hBitmap = CreateDIBitmap(hDC, 
							(LPBITMAPINFOHEADER)lpDIBHdr, 
							CBM_INIT, 
							lpDIBBits, 
							(LPBITMAPINFO)lpDIBHdr, 
							DIB_RGB_COLORS);
 
    // restore previous palette 
    if (hOldPal) 
        SelectPalette(hDC, hOldPal, FALSE); 
 
    // clean up 
    ReleaseDC(NULL, hDC); 
    GlobalUnlock(hDIB); 
 
    // return handle to the bitmap 
    return hBitmap; 
} 
 
 
/************************************************************************* 
 * 
 * BitmapToDIB() 
 * 
 * Parameters: 
 * 
 * HBITMAP hBitmap  - specifies the bitmap to convert 
 * 
 * HPALETTE hPal    - specifies the palette to use with the bitmap 
 * 
 * Return Value: 
 * 
 * HDIB             - identifies the device-dependent bitmap 
 * 
 * Description: 
 * 
 * This function creates a DIB from a bitmap using the specified palette. 
 * 
 ************************************************************************/ 
HDIB BitmapToDIB(HBITMAP hBitmap, HPALETTE hPal) 
{ 
    BITMAP              bm;         // bitmap structure 
    BITMAPINFOHEADER    bi;         // bitmap header 
    LPBITMAPINFOHEADER  lpbi;       // pointer to BITMAPINFOHEADER 
    DWORD               dwLen;      // size of memory block 
    HANDLE              hDIB, h;    // handle to DIB, temp handle 
    HDC                 hDC;        // handle to DC 
    WORD                biBits;     // bits per pixel 
 
    // check if bitmap handle is valid 
 
    if (!hBitmap) 
        return NULL; 
 
    // fill in BITMAP structure, return NULL if it didn't work 
 
    if (!GetObject(hBitmap, sizeof(bm), (LPBYTE)&bm)) 
        return NULL; 
 
    // if no palette is specified, use default palette 
 
    if (hPal == NULL) 
        hPal = (HPALETTE)GetStockObject(DEFAULT_PALETTE); 
 
    // calculate bits per pixel 
 
    biBits = bm.bmPlanes * bm.bmBitsPixel; 
 
    // make sure bits per pixel is valid 
 
    if (biBits <= 1) 
        biBits = 1; 
    else if (biBits <= 4) 
        biBits = 4; 
    else if (biBits <= 8) 
        biBits = 8; 
    else // if greater than 8-bit, force to 24-bit 
        biBits = 24; 
 
    // initialize BITMAPINFOHEADER 
 
    bi.biSize = sizeof(BITMAPINFOHEADER); 
    bi.biWidth = bm.bmWidth; 
    bi.biHeight = bm.bmHeight; 
    bi.biPlanes = 1; 
    bi.biBitCount = biBits; 
    bi.biCompression = BI_RGB; 
    bi.biSizeImage = 0; 
    bi.biXPelsPerMeter = 0; 
    bi.biYPelsPerMeter = 0; 
    bi.biClrUsed = 0; 
    bi.biClrImportant = 0; 
 
    // calculate size of memory block required to store BITMAPINFO 
 
    dwLen = bi.biSize + PaletteSize((LPBYTE)&bi); 
 
    // get a DC 
 
    hDC = GetDC(NULL); 
 
    // select and realize our palette 
 
    hPal = SelectPalette(hDC, hPal, FALSE); 
    RealizePalette(hDC);