将HBITMAP保存为Bmp文件,发现Bmp文件颜色不正确,哪位老大帮俺看看

[codemon]

将HBITMAP保存为Bmp文件,发现Bmp文件颜色不正确,哪位老大帮俺看看

BOOL Save(LPCTSTR lpszFileName,HBITMAP hBmp,BITMAPINFO* pBi)
{
BITMAPINFOHEADER* pBh=(BITMAPINFOHEADER*)pBi;
LPBYTE lpBits = new BYTE[pBh->biSizeImage];
if (!lpBits) return FALSE;

HDC hdc=GetDC(NULL);
if (!hdc ||
!GetDIBits(hdc,hBmp, 0, (WORD)(pBh->biHeight),lpBits,pBi,DIB_RGB_COLORS))
{
if(hdc) ReleaseDC(NULL,hdc);
delete lpBits;
return FALSE;
}

ReleaseDC(NULL,hdc);

FILE* pFile=NULL;
pFile = fopen(lpszFileName, "w+b");
if(!pFile)
{
delete lpBits;
return FALSE;
}


BITMAPFILEHEADER hdr;
hdr.bfType = (WORD)('M'<<8)|'B';
hdr.bfSize = (DWORD) (sizeof(BITMAPFILEHEADER) + pBh->biSize + pBh->biClrUsed* sizeof(RGBQUAD) + pBh->biSizeImage);
hdr.bfReserved1 = 0;
hdr.bfReserved2 = 0;
hdr.bfOffBits = (DWORD) sizeof(BITMAPFILEHEADER) + pBh->biSize + pBh->biClrUsed * sizeof(RGBQUAD);

fseek(pFile,0,SEEK_SET);
fwrite(&hdr,sizeof(BYTE),sizeof(BITMAPFILEHEADER),pFile);
fwrite(pBh,sizeof(BYTE), sizeof(BITMAPINFOHEADER)+pBh->biClrUsed * sizeof(RGBQUAD),pFile);
fwrite(lpBits,sizeof(BYTE),pBh->biSizeImage,pFile);
fclose(pFile);

delete lpBits;
return TRUE;
}

[codemon]

等待ing....

[s_phoenix]

gz
我最近听别人说什么“调色板”。我也不太懂。看看后面的大侠了，是否和这个有关？

[wuxuan]

see this.
http://www.codeproject.com/bitmap/cximage.asp

[nzzt]

这个函数绝对没有问题。
出问题的地方可能是：
1。BITMAPINFO 没算对
2。HBITMAP 不是用当前系统的DC抓下来的。你传个HDC进来，用传进来的HDC看看。

MSDN上的例子：

PBITMAPINFO CreateBitmapInfoStruct(HWND hwnd, HBITMAP hBmp)
{
BITMAP bmp;
PBITMAPINFO pbmi;
WORD cClrBits;

// Retrieve the bitmap color format, width, and height.
if (!GetObject(hBmp, sizeof(BITMAP), (LPSTR)&bmp))
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 the 24-bit-per-pixel format.

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.
// For Windows NT, the width must be DWORD aligned unless
// the bitmap is RLE compressed. This example shows this.
// For Windows 95/98/Me, the width must be WORD 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;
} The following example code defines a function that initializes the remaining structures, retrieves the array of palette indices, opens the file, copies the data, and closes the file.

void CreateBMPFile(HWND hwnd, 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)
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))
{
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)
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))
{
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))
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))
errhandler("WriteFile", hwnd);

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

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

[codemon]

解决啦！！！
原来是 biCompression 的值不对 :)

[zhangdaqiang]

http://www.codeproject.com/bitmap/cximage.asp

[codemon]

wuxuan(真心英雄)
公司限制,只能上CSDN,能不能帮个忙贴过来?谢了先。

[zzhcom]

只能说你们公司的网管孤陋寡闻了，codeproject这么经典的网站都不能上，有这样的公司
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