一个非常难的问题

[gcmandwxj]

请问大虾,如何显示非bmp格式的图形文件,且截取图像的某一指定范围，保存为bmp格式的图形文件.

[Kevin_qing]

你想怎么显示,象ACDSEE用DirectX? or GDI?

[Holly]

在WINDOWS中系统不支持许多的格式直接显示，大多数的图形格式都需要转换为BMP格式处理，在WINDOW98/2000中增加了对JPG和PNG格式的直接支持可以直接用StretchDIBits操作。

[opkj]

恐怕大多数格式是先转换为DIB格式吧。

[gcmandwxj]

我是指在窗口中显示bmp,gif,jpg格式的图形文件，且截取图像的某一指定范围，保存为bmp格式的图形文件.

[Jackyin]

a

[skt642]

10971关注！

[Kevin_qing]

找个图形库用用就是了

[seesi]

急不急的啊？不急的话，过几天我整理好后给你。急得话，等今天下午给你贴上来。

[seesi]

//加载图象
LoadPictureFromFile(HDC hdc, LPCTSTR szFile, CBitmap *pBitmap, CSize &mSize)
{
// open file
HANDLE hFile = CreateFile(szFile, GENERIC_READ, 0, NULL, OPEN_EXISTING, 0, NULL);
_ASSERTE(INVALID_HANDLE_VALUE != hFile);

// get file size
DWORD dwFileSize = GetFileSize(hFile, NULL);
_ASSERTE(-1 != dwFileSize);

LPVOID pvData = NULL;
// alloc memory based on file size
HGLOBAL hGlobal = GlobalAlloc(GMEM_MOVEABLE, dwFileSize);
_ASSERTE(NULL != hGlobal);

pvData = GlobalLock(hGlobal);
_ASSERTE(NULL != pvData);

DWORD dwBytesRead = 0;
// read file and store in global memory
BOOL bRead = ReadFile(hFile, pvData, dwFileSize, &dwBytesRead, NULL);
_ASSERTE(FALSE != bRead);
GlobalUnlock(hGlobal);
CloseHandle(hFile);

LPSTREAM pstm = NULL;
// create IStream* from global memory
HRESULT hr = CreateStreamOnHGlobal(hGlobal, TRUE, &pstm);
_ASSERTE(SUCCEEDED(hr) && pstm);

// Create IPicture from image file
LPPICTURE gpPicture;

hr = ::OleLoadPicture(pstm, dwFileSize, FALSE, IID_IPicture, (LPVOID *)&gpPicture);

_ASSERTE(SUCCEEDED(hr) && gpPicture);
pstm->Release();

OLE_HANDLE m_picHandle;
/*
long hmWidth, hmHeight;
gpPicture->get_Width(&hmWidth);
gpPicture->get_Height(&hmHeight);
int nWidth = MulDiv(hmWidth, GetDeviceCaps(hdc, LOGPIXELSX), HIMETRIC_INCH);
int nHeight = MulDiv(hmHeight, GetDeviceCaps(hdc, LOGPIXELSY), HIMETRIC_INCH);
*/
gpPicture->get_Handle(&m_picHandle);
pBitmap->DeleteObject();
pBitmap->Attach((HGDIOBJ) m_picHandle);

BITMAP bm;
GetObject(pBitmap->m_hObject, sizeof(bm), &bm);
mSize.cx = bm.bmWidth; //nWidth;
mSize.cy = bm.bmHeight; //nHeight;
}

//截取图象
void CopyBitmap(CDC *dc, CBitmap &mRes, const CBitmap &hbmp, RECT r)
{
if(!hbmp.m_hObject) return;
int w = r.right - r.left,
h = r.bottom - r.top;

CDC memdc, hDC;

mRes.CreateCompatibleBitmap(dc, w, h);

hDC.CreateCompatibleDC(dc);
hDC.SelectObject((HBITMAP) mRes);

memdc.CreateCompatibleDC(dc);
memdc.SelectObject(hbmp);

hDC.StretchBlt(0, 0, w, h, &memdc, r.left, r.top, w, h, SRCCOPY);
hDC.DeleteDC();
memdc.DeleteDC();
}

//DDB转变为DIB，准备保存

// DDBToDIB - Creates a DIB from a DDB
// bitmap - Device dependent bitmap
// dwCompression - Type of compression - see BITMAPINFOHEADER
// pPal - Logical palette
HANDLE DDBToDIB(CBitmap &bitmap, DWORD dwCompression, CPalette *pPal)
{
BITMAP bm;
BITMAPINFOHEADER bi;
LPBITMAPINFOHEADER lpbi;
DWORD dwLen;
HANDLE hDIB;
HANDLE handle;
HDC hDC;
HPALETTE hPal;


ASSERT( bitmap.GetSafeHandle() );

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

// If a palette has not been supplied use defaul palette
hPal=NULL;
if(pPal!=NULL)
{
hPal = (HPALETTE) pPal->GetSafeHandle();
}
if (hPal==NULL)
hPal = (HPALETTE) GetStockObject(DEFAULT_PALETTE);

// Get bitmap information
bitmap.GetObject(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
int 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.GetSafeHandle(), 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
BOOL bGotBits = GetDIBits( hDC, (HBITMAP)bitmap.GetSafeHandle(),
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;
}

//保存DIB为位图文件
int SaveBmp(HANDLE hDib, LPSTR filename)
{
/*
BITMAPFILEHEADER bfh;
BITMAPINFOHEADER *lpbi=(BITMAPINFOHEADER*)hDib;

bfh.bfType=0x4D42; //BM
bfh.bfSize=sizeof(bfh)+GlobalSize(hData);
bfh.bfReserved1=bfh.bfReserved2=0;
int colors=1<lpbi->biBitCount;
if(colors>256) colors=0;
bfh.bfOffBits=sizeof(bfh)+lpbi->biSize+colors*sizeof(RGBQUAD);

HANDLE hFile=CreateFile(filename,GENERIC_WRITE
,FILE_SHARE_READ|FILE_SHARE_WRITE,NULL,CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL,NULL);
if(hFile)
{
DWORD write;
WriteFile(hFile,&bfh,sizeof(bfh),&write,NULL);
WriteFile(hFile,lpbi,GlobalSize(hData),&write,NULL);
int i=sizeof(hData);
CloseHandle(hFile);
return true;
}
return false;
*/
CFile file;
if(!file.Open(filename,CFile::modeCreate|CFile::modeWrite))
return FALSE;

BITMAPFILEHEADER bmfHdr; // Header for Bitmap file
LPBITMAPINFOHEADER lpBI; // Pointer to DIB info structure
DWORD dwDIBSize;

if (hDib == NULL)
{
file.Close();
return FALSE;
}

/*
* Get a pointer to the DIB memory, the first of which contains
* a BITMAPINFO structure
*/
lpBI = (LPBITMAPINFOHEADER) ::GlobalLock((HGLOBAL) hDib);
if (lpBI == NULL)
{
file.Close();
return FALSE;
}

if (!((*(LPDWORD)(lpBI)) == sizeof(BITMAPINFOHEADER)))
{
::GlobalUnlock((HGLOBAL) hDib);
file.Close();
return FALSE; // It's an other-style DIB (save not supported)
}

/*
* Fill in the fields of the file header
*/

/* Fill in file type (first 2 bytes must be "BM" for a bitmap) */
bmfHdr.bfType = ((WORD) ('M' << 8) | 'B'); // "BM"

// Calculating the size of the DIB is a bit tricky (if we want to
// do it right). The easiest way to do this is to call GlobalSize()
// on our global handle, but since the size of our global memory may have
// been padded a few bytes, we may end up writing out a few too
// many bytes to the file (which may cause problems with some apps).
//
// So, instead let's calculate the size manually (if we can)
//
// First, find size of header plus size of color table. Since the
// first DWORD in both BITMAPINFOHEADER and BITMAPCOREHEADER conains
// the size of the structure, let's use this.

dwDIBSize = *(LPDWORD)lpBI + PaletteSize((LPSTR)lpBI); // Partial Calculation

// Now calculate the size of the image

if ((lpBI->biCompression == BI_RLE8) || (lpBI->biCompression == BI_RLE4))
{
// It's an RLE bitmap, we can't calculate size, so trust the
// biSizeImage field

dwDIBSize += lpBI->biSizeImage;
}
else
{
DWORD dwBmBitsSize; // Size of Bitmap Bits only

// It's not RLE, so size is Width (DWORD aligned) * Height

dwBmBitsSize = WIDTHBYTES((lpBI->biWidth)*((DWORD)lpBI->biBitCount)) * lpBI->biHeight;

dwDIBSize += dwBmBitsSize;

// Now, since we have calculated the correct size, why don't we
// fill in the biSizeImage field (this will fix any .BMP files which
// have this field incorrect).

lpBI->biSizeImage = dwBmBitsSize;
}


// Calculate the file size by adding the DIB size to sizeof(BITMAPFILEHEADER)

bmfHdr.bfSize = dwDIBSize + sizeof(BITMAPFILEHEADER);
bmfHdr.bfReserved1 = 0;
bmfHdr.bfReserved2 = 0;

/*
* Now, calculate the offset the actual bitmap bits will be in
* the file -- It's the Bitmap file header plus the DIB header,
* plus the size of the color table.
*/
bmfHdr.bfOffBits = (DWORD)sizeof(BITMAPFILEHEADER) + lpBI->biSize
+ PaletteSize((LPSTR)lpBI);
TRY
{
// Write the file header
file.Write((LPSTR)&bmfHdr, sizeof(BITMAPFILEHEADER));
//
// Write the DIB header and the bits
//
file.WriteHuge(lpBI, dwDIBSize);
}
CATCH (CFileException, e)
{
::GlobalUnlock((HGLOBAL) hDib);
THROW_LAST();
}
END_CATCH

::GlobalUnlock((HGLOBAL) hDib);
file.Close();
return TRUE;
}



简直累死了，行不行啊？？