c++ - 尝试为多种 BPP 格式创建保存位图功能

Question

我有一个 C++ MFC 项目，我需要在其中翻转可以采用不同格式的位图，然后保存它。我在制作以多种格式保存位图的功能时遇到问题。

当我尝试启用 ATL(Active Template Libraray)以使用 CImage 中的函数时，我添加的 #includes 破坏了项目。在尝试了几种不同的方法后，我放弃了。

因为我不能使用 CImage，所以我查看了 Microsoft 的保存位图图像的示例。问题是他们的示例不适用于 24 位位图以外的任何图像。

这是来自 MSDN 的函数。

PBITMAPINFO BitmapTools::CreateBitmapInfoStruct(HBITMAP hBmp)
{ 
BITMAP bmp; 
PBITMAPINFO pbmi; 
WORD    cClrBits; 

// Retrieve the bitmap color format, width, and height.  
if (!GetObjectW(hBmp, sizeof(BITMAP), (LPSTR)&bmp)) 
    return pbmi;
// errhandler("GetObject", hwnd); 

// Convert the color format to a count of bits.  
cClrBits = (WORD)(bmp.bmPlanes * bmp.bmBitsPixel); 
if (cClrBits == 1) 
    cClrBits = 1; 
else if (cClrBits <= 4) 
    cClrBits = 4; 
else if (cClrBits <= 8) 
    cClrBits = 8; 
else if (cClrBits <= 16) 
    cClrBits = 16; 
else if (cClrBits <= 24) 
    cClrBits = 24; 
else cClrBits = 32; 

// Allocate memory for the BITMAPINFO structure. (This structure  
// contains a BITMAPINFOHEADER structure and an array of RGBQUAD  
// data structures.)  

if (cClrBits < 24)
{
    pbmi = (PBITMAPINFO) LocalAlloc(LPTR, 
        sizeof(BITMAPINFOHEADER) + 
        sizeof(RGBQUAD) * (1<< cClrBits)); 

    // There is no RGBQUAD array for these formats: 24-bit-per-pixel or 32-bit-per-pixel 
}
else
{
    pbmi = (PBITMAPINFO) LocalAlloc(LPTR, sizeof(BITMAPINFOHEADER)); 
}

// Initialize the fields in the BITMAPINFO structure.  

pbmi->bmiHeader.biSize = sizeof(BITMAPINFOHEADER); 
pbmi->bmiHeader.biWidth = bmp.bmWidth; 
pbmi->bmiHeader.biHeight = bmp.bmHeight; 
pbmi->bmiHeader.biPlanes = bmp.bmPlanes; 
pbmi->bmiHeader.biBitCount = bmp.bmBitsPixel; 
if (cClrBits < 24) 
    pbmi->bmiHeader.biClrUsed = (1<<cClrBits); 

// If the bitmap is not compressed, set the BI_RGB flag.  
pbmi->bmiHeader.biCompression = BI_RGB; 

// Compute the number of bytes in the array of color  
// indices and store the result in biSizeImage.  
// The width must be DWORD aligned unless the bitmap is 
// RLE compressed. 
pbmi->bmiHeader.biSizeImage = ((pbmi->bmiHeader.biWidth * cClrBits +31) & ~31) /8
    * pbmi->bmiHeader.biHeight; 
// Set biClrImportant to 0, indicating that all of the  
// device colors are important.  
pbmi->bmiHeader.biClrImportant = 0; 
return pbmi; 
} 

创建文件的函数:

void BitmapTools::CreateBMPFile(LPTSTR pszFile, PBITMAPINFO pbi, HBITMAP hBMP, HDC hDC) 
{ 
HANDLE hf;                  // file handle  
BITMAPFILEHEADER hdr;       // bitmap file-header  
PBITMAPINFOHEADER pbih;     // bitmap info-header  
LPBYTE lpBits;              // memory pointer  
DWORD dwTotal;              // total count of bytes  
DWORD cb;                   // incremental count of bytes  
BYTE *hp;                   // byte pointer  
DWORD dwTmp; 

pbih = (PBITMAPINFOHEADER) pbi; 
lpBits = (LPBYTE) GlobalAlloc(GMEM_FIXED, pbih->biSizeImage);

if (!lpBits) 
    return;//errhandler("GlobalAlloc", hwnd); 


// Retrieve the color table (RGBQUAD array) and the bits  
// (array of palette indices) from the DIB.  
if (!GetDIBits(hDC, hBMP, 0, (WORD) pbih->biHeight, lpBits, pbi, 
    DIB_RGB_COLORS)) 
{
    return;//errhandler("GetDIBits", hwnd); 
}

// Create the .BMP file.  
hf = CreateFile(pszFile, 
    GENERIC_READ | GENERIC_WRITE, 
    (DWORD) 0, 
    NULL, 
    CREATE_ALWAYS, 
    FILE_ATTRIBUTE_NORMAL, 
    (HANDLE) NULL); 
if (hf == INVALID_HANDLE_VALUE) 
    return;//errhandler("CreateFile", hwnd); 
hdr.bfType = 0x4d42;        // 0x42 = "B" 0x4d = "M"  
// Compute the size of the entire file.  
hdr.bfSize = (DWORD) (sizeof(BITMAPFILEHEADER) + 
    pbih->biSize + pbih->biClrUsed 
    * sizeof(RGBQUAD) + pbih->biSizeImage); 
hdr.bfReserved1 = 0; 
hdr.bfReserved2 = 0; 

// Compute the offset to the array of color indices.  
hdr.bfOffBits = (DWORD) sizeof(BITMAPFILEHEADER) + 
    pbih->biSize + pbih->biClrUsed 
    * sizeof (RGBQUAD); 

// Copy the BITMAPFILEHEADER into the .BMP file.  
if (!WriteFile(hf, (LPVOID) &hdr, sizeof(BITMAPFILEHEADER), 
    (LPDWORD) &dwTmp,  NULL)) 
{
    return;//errhandler("WriteFile", hwnd); 
}

// Copy the BITMAPINFOHEADER and RGBQUAD array into the file.  
if (!WriteFile(hf, (LPVOID) pbih, sizeof(BITMAPINFOHEADER) 
    + pbih->biClrUsed * sizeof (RGBQUAD), 
    (LPDWORD) &dwTmp, ( NULL)))
    return;//errhandler("WriteFile", hwnd); 

// Copy the array of color indices into the .BMP file.  
dwTotal = cb = pbih->biSizeImage; 
hp = lpBits; 
if (!WriteFile(hf, (LPSTR) hp, (int) cb, (LPDWORD) &dwTmp,NULL)) 
    return;// errhandler("WriteFile", hwnd); 

// Close the .BMP file.  
if (!CloseHandle(hf)) 
    return;// errhandler("CloseHandle", hwnd); 

// Free memory.  
GlobalFree((HGLOBAL)lpBits);
}

出于某种原因，当有调色板时，最后一个功能不起作用。如果有人有任何修改此建议的提示，我将不胜感激。

谢谢，-HL

已编辑:基本上，第一个函数从加载的位图中获取并存储 BitmapInfo。这是我的 H 文件中声明的函数。为简洁起见，我没有发布 .cpp 文件中已正常工作的所有方法。

class BitmapTools : public CBitmap
{
public:
// PaddedWidth = ((Width * (BitsPerPixel / 8)) + 3) & (~3)
// ScanPadding = PaddedWidth - (Width * ( BitsPerPixel / 8 ));
HBITMAP H_Bitmap;   
PBITMAPINFO PBMI;
// If the color depth is 8 bits or lower there will be a color palette/table. 
RGBQUAD colortable;
PBITMAPINFO CreateBitmapInfoStruct(HBITMAP hBmp);
void CreateBMPFile(LPTSTR pszFile, PBITMAPINFO pbi, HBITMAP hBMP, HDC hDC);
bool LoadAttachBitmap(LPCTSTR bmpfile);
void GetWidthAndHeight (int* pw, int* ph) const;
void Invert (BOOL bLateral);
void InvertAndFlip();
};

调用方法:

BitmapTools tools;
if (!tools.LoadAttachBitmap("test.bmp"))
{
    return;
}
tools.InvertAndFlip();
tools.PBMI = tools.CreateBitmapInfoStruct(tools.H_Bitmap);
HDC dc = CreateCompatibleDC(NULL); 
tools.CreateBMPFile("temp.bmp", tools.PBMI, tools.H_Bitmap, dc);
return;

Answer 1

我认为调色板图像存在内存分配问题，加上 header 数据错误。这个应该可以工作:

BOOL SaveHBitmap(const char* filename, HBITMAP hbitmap, HDC hdc)
{
    BITMAP bitmap;
    if (!GetObject(hbitmap, sizeof(BITMAP), (void*)&bitmap))
        return FALSE;

    // Convert the color format to a count of bits.  
    WORD clrbits = (WORD)(bitmap.bmPlanes * bitmap.bmBitsPixel);
    if (clrbits == 1) clrbits = 1;
    else if (clrbits <= 4)  clrbits = 4;
    else if (clrbits <= 8)  clrbits = 8;
    else if (clrbits <= 16) clrbits = 16;
    else if (clrbits <= 24) clrbits = 24;
    else clrbits = 32;

    //clrUsed is zero for 24 bit and higher
    int clrUsed = (clrbits <= 8) ? (1 << clrbits) : 0;
    TRACE("clrUsed %d\n", clrUsed);

    int bitmapInfoSize = sizeof(BITMAPINFOHEADER) + sizeof(RGBQUAD) * clrUsed;
    PBITMAPINFO bitmapInfo = (PBITMAPINFO)new char[bitmapInfoSize];
    memset(bitmapInfo, 0, bitmapInfoSize);

    // Initialize the fields in the BITMAPINFO structure.  
    bitmapInfo->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
    bitmapInfo->bmiHeader.biWidth = bitmap.bmWidth;
    bitmapInfo->bmiHeader.biHeight = bitmap.bmHeight;
    bitmapInfo->bmiHeader.biPlanes = bitmap.bmPlanes;
    bitmapInfo->bmiHeader.biBitCount = bitmap.bmBitsPixel;
    bitmapInfo->bmiHeader.biClrUsed = clrUsed;
    bitmapInfo->bmiHeader.biCompression = BI_RGB;

    // Compute the number of bytes in the array of color indices and store the result in biSizeImage.  
    // The width must be DWORD aligned unless the bitmap is RLE compressed. 
    int dibSize = ((bitmap.bmWidth * clrbits + 31) & ~31) / 8 * bitmap.bmHeight;
    char* dib = new char[dibSize];

    bitmapInfo->bmiHeader.biSizeImage = dibSize;

    // Set biClrImportant to 0, indicating that all of the device colors are important.  
    bitmapInfo->bmiHeader.biClrImportant = 0;

    PBITMAPINFOHEADER bmpInfoHeader = (PBITMAPINFOHEADER)bitmapInfo;

    if (!GetDIBits(hdc, hbitmap, 0, bmpInfoHeader->biHeight, dib, bitmapInfo, 0))
    {
        delete bitmapInfo;
        delete[]dib;
        return FALSE;
    }

    BITMAPFILEHEADER bmpFileHeader = { 0 };
    bmpFileHeader.bfType = 0x4d42;
    bmpFileHeader.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + clrUsed * sizeof(RGBQUAD);
    bmpFileHeader.bfSize = bmpFileHeader.bfOffBits + dibSize;

    HANDLE hfile = CreateFile(filename, GENERIC_READ | GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
    if (hfile != INVALID_HANDLE_VALUE)
    {
        DWORD dwTmp;
        WriteFile(hfile, (void*)&bmpFileHeader, sizeof(BITMAPFILEHEADER), &dwTmp, NULL);
        WriteFile(hfile, (void*)bmpInfoHeader, sizeof(BITMAPINFOHEADER) + clrUsed * sizeof(RGBQUAD), &dwTmp, NULL);
        WriteFile(hfile, (void*)dib, dibSize, &dwTmp, NULL);
        CloseHandle(hfile);
    }

    delete bitmapInfo;
    delete[]dib;

    return TRUE;
}

void foo()
{
    const char* filename = "c:\\test\\test8bit.bmp";

    if (IDOK != ::MessageBox(0, "this will over-write the file", 0, MB_OKCANCEL))
        return;

    HBITMAP hbitmap = (HBITMAP)LoadImage(0, filename, IMAGE_BITMAP, 0, 0,
        LR_CREATEDIBSECTION | LR_DEFAULTSIZE | LR_LOADFROMFILE);
    if (!hbitmap) return;

    //modify hbitmap here
    //...

    HDC hdc = CreateCompatibleDC(0);
    SaveHBitmap(filename, hbitmap, hdc);
    DeleteDC(hdc);

    ShellExecute(0, 0, filename, 0, 0, SW_SHOW);
}