BOOL BMP24to8(
char *szSourceFile,
char *
szTargetFile)
{
HANDLE hSourceFile=INVALID_HANDLE_VALUE,hTargetFile=
INVALID_HANDLE_VALUE;
DWORD dwSourceSize=
0,dwTargetSize=
0;
PBYTE pSource=NULL,pTarget=
NULL;
hSourceFile=
CreateFile(szSourceFile,GENERIC_READ,FILE_SHARE_READ,NULL,
OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,NULL);
if(hSourceFile==
INVALID_HANDLE_VALUE)
return FALSE;
dwSourceSize=
GetFileSize(hSourceFile,NULL);
pSource=
(PBYTE)VirtualAlloc(NULL,dwSourceSize,MEM_COMMIT,PAGE_READWRITE);
//分配空间失败或者文件太小（BMP文件不可能小于54个字节）
if(pSource==NULL||dwSourceSize<=
54)
{
CloseHandle(hSourceFile);
return FALSE;
}
DWORD dwTemp=
0;
ReadFile(hSourceFile,pSource,dwSourceSize,&
dwTemp,NULL);
BITMAPFILEHEADER *pSourceFileHeader=(BITMAPFILEHEADER*
)pSource;
BITMAPINFOHEADER *pSourceInfoHeader=(BITMAPINFOHEADER*)(pSource+
sizeof(BITMAPFILEHEADER));
//不是BMP文件或者不是24位真彩色
if(pSourceFileHeader->bfType!=
0x4d42||pSourceInfoHeader->biBitCount!=
24)
{
CloseHandle(hSourceFile);
VirtualFree(pSource,NULL,MEM_RELEASE);
return FALSE;
}
CloseHandle(hSourceFile);
LONG nWidth=pSourceInfoHeader->
biWidth;
LONG nHeight=pSourceInfoHeader->
biHeight;
LONG nSourceWidth=nWidth*
3;
if(nSourceWidth%
4) nSourceWidth=(nSourceWidth/
4+
1)*
4;
LONG nTargetWidth=nWidth;
if(nTargetWidth%
4) nTargetWidth=(nTargetWidth/
4+
1)*
4;
dwTargetSize=
sizeof(BITMAPFILEHEADER)+
sizeof(BITMAPINFOHEADER)+
sizeof(RGBQUAD)*
256+nHeight*
nTargetWidth;
pTarget=
(PBYTE)VirtualAlloc(NULL,dwTargetSize,MEM_COMMIT,PAGE_READWRITE);
memset(pTarget,0,dwTargetSize);
if(pTarget==
NULL)
{
VirtualFree(pTarget,NULL,MEM_RELEASE <a href=
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);
return FALSE;
}
BITMAPFILEHEADER *pTargetFileHeader=(BITMAPFILEHEADER *
)pTarget;
BITMAPINFOHEADER *pTargetInfoHeader =
(BITMAPINFOHEADER *)(pTarget+
sizeof(BITMAPFILEHEADER));
pTargetFileHeader->bfType=pSourceFileHeader->
bfType;
pTargetFileHeader->bfSize=
dwTargetSize;
pTargetFileHeader->bfReserved1=
0;
pTargetFileHeader->bfReserved2=
0;
pTargetFileHeader->bfOffBits=
sizeof(BITMAPFILEHEADER)
+
sizeof(BITMAPINFOHEADER)+
sizeof(RGBQUAD)*
256;
pTargetInfoHeader->biBitCount=
8;
pTargetInfoHeader->biClrImportant=
0;
pTargetInfoHeader->biClrUsed=
256;
pTargetInfoHeader->biCompression=
BI_RGB;
pTargetInfoHeader->biHeight=pSourceInfoHeader->
biHeight;
pTargetInfoHeader->biPlanes=
1;
pTargetInfoHeader->biSize=
sizeof(BITMAPINFOHEADER);
pTargetInfoHeader->biSizeImage=nHeight*
nTargetWidth;
pTargetInfoHeader->biWidth=pSourceInfoHeader->
biWidth;
pTargetInfoHeader->biXPelsPerMeter=pSourceInfoHeader->
biXPelsPerMeter;
pTargetInfoHeader->biYPelsPerMeter=pSourceInfoHeader->
biYPelsPerMeter;
RGBQUAD *
pRgb;
for(
int i=
0;i<
256;i++)
//初始化8位灰度图的调色板信息
{
pRgb = (RGBQUAD*)(pTarget+
sizeof(BITMAPFILEHEADER)
+
sizeof(BITMAPINFOHEADER)+i*
sizeof(RGBQUAD));
pRgb->rgbBlue=i;pRgb->rgbGreen=i;pRgb->rgbRed=i;pRgb->rgbReserved=
0;
}
for (
int m=
0;m<nHeight;m++)
//转化真彩色图为灰度图
{
for(
int n=
0;n<nWidth;n++
)
{
pTarget[pTargetFileHeader->bfOffBits+m*nTargetWidth+n] =
pSource[pSourceFileHeader->bfOffBits+m*nSourceWidth+n*
3]*
0.114
+pSource[pSourceFileHeader->bfOffBits+m*nSourceWidth+n*
3+
1]*
0.587
+pSource[pSourceFileHeader->bfOffBits+m*nSourceWidth+n*
3+
2]*
0.299;
}
}
hTargetFile =
CreateFile(szTargetFile,GENERIC_WRITE,FILE_SHARE_WRITE,
NULL,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,NULL);
BOOL stat=WriteFile(hTargetFile,pTarget,dwTargetSize,&
dwTemp,NULL);
CloseHandle(hTargetFile);
VirtualFree(pSource,NULL,MEM_RELEASE);
VirtualFree(pTarget,NULL,MEM_RELEASE);
return stat;
}
转载于:https://www.cnblogs.com/luyuxibaby/p/5217428.html
相关资源：24位图转8位图像
