Use GDI + to convert BMP bitmap to JPG Bitmap (and convert com Object IPicture to jpg)

First, the header file contains the GDI + header and library.

 

# Ifndef ULONG_PTR
# Define ULONG_PTR unsigned long *
# Include "GdiPlus. h"
Using namespace Gdiplus;
# Pragma comment (lib, "gdiplus. lib ")
# Include <atlconv. h>
# Endif

 

Define related member variables in the class

GdiplusStartupInput m_gdiplusStartupInput;
ULONG_PTR m_gdiplusToken;

 

Initialize gdi +

GdiplusStartup (& m_gdiplusToken, & m_gdiplusStartupInput, NULL );

 

Destroy gdi + at end

GdiplusShutdown (m_gdipluw.en );

 

Conversion functions

BOOL CtojpgDlg: MBmpToMImage (CFile & cbfBmp, CFile & cbfImage, CString strType) <br/>{< br/> int iBmpSize = cbfBmp. getLength (); <br/> HGLOBAL hMemBmp = GlobalAlloc (GMEM_FIXED, iBmpSize); <br/> if (hMemBmp = NULL) return FALSE; <br/> IStream * pStmBmp = NULL; <br/> CreateStreamOnHGlobal (hMemBmp, FALSE, & pStmBmp); <br/> if (pStmBmp = NULL) <br/>{< br/> GlobalFree (hMemBmp); <br/> return FALSE; <br/>}< br/> BYTE * PbyBmp = (BYTE *) GlobalLock (hMemBmp); <br/> cbfBmp. seekToBegin (); <br/> cbfBmp. read (pbyBmp, iBmpSize); </p> <p> Image * imImage = NULL; <br/> imImage = Image: FromStream (pStmBmp, FALSE ); <br/> if (imImage = NULL) <br/>{< br/> GlobalUnlock (hMemBmp); <br/> GlobalFree (hMemBmp ); <br/> return FALSE; <br/>}< br/> USES_CONVERSION; <br/> CLSID clImageClsid; <br/> GetImageCLSID (_ T ("image/jpeg"), & clImageClsid); </p> <p> HGLOBAL hMemImage = GlobalAlloc (GMEM_MOVEABLE, 0); <br/> if (hMemImage = NULL) <br/>{< br/> pStmBmp-> Release (); <br/> GlobalUnlock (hMemBmp); <br/> GlobalFree (hMemBmp); <br/> if (imImage! = NULL) delete imImage; <br/> return FALSE; <br/>}< br/> IStream * pStmImage = NULL; <br/> CreateStreamOnHGlobal (hMemImage, TRUE, & pStmImage); <br/> if (pStmImage = NULL) <br/>{< br/> pStmBmp-> Release (); <br/> GlobalUnlock (hMemBmp ); <br/> GlobalFree (hMemBmp); <br/> GlobalFree (hMemImage); <br/> if (imImage! = NULL) delete imImage; <br/> return FALSE; <br/>}< br/> imImage-> Save (pStmImage, & clImageClsid ); <br/> if (pStmImage = NULL) <br/>{< br/> pStmBmp-> Release (); <br/> pStmImage-> Release (); <br/> GlobalUnlock (hMemBmp); <br/> GlobalFree (hMemImage); <br/> if (imImage! = NULL) delete imImage; <br/> return FALSE; <br/>}< br/> LARGE_INTEGER liBegin = {0}; <br/> pStmImage-> Seek (liBegin, STREAM_SEEK_SET, NULL); <br/> BYTE * pbyImage = (BYTE *) GlobalLock (hMemImage); <br/> cbfImage. seekToBegin (); <br/> cbfImage. write (pbyImage, GlobalSize (hMemImage); </p> <p> if (imImage! = NULL) delete imImage; <br/> pStmBmp-> Release (); <br/> pStmImage-> Release (); <br/> GlobalUnlock (hMemBmp ); <br/> GlobalUnlock (hMemImage); <br/> GlobalFree (hMemBmp); <br/> GlobalFree (hMemImage); <br/> return TRUE; <br/>}</p> <p> BOOL CtojpgDlg: GetImageCLSID (const WCHAR * format, CLSID * pCLSID) <br/>{< br/> UINT num = 0; <br/> UINT size = 0; </p> <p> ImageCodecInfo * pImageCodecInfo = NULL; <br/> GetImageEncodersSize (& num, & size); <br/> if (size = 0) {<br/> return FALSE; <br/>}< br/> pImageCodecInfo = (ImageCodecInfo *) (malloc (size); <br/> if (pImageCodecInfo = NULL) <br/> return FALSE; <br/> GetImageEncoders (num, size, pImageCodecInfo ); </p> <p> // Find for the support of format for image in the windows <br/> for (UINT I = 0; I <num; ++ I) <br/>{< br/> // MimeType: Depiction for the program image <br/> if (wcscmp (pImageCodecInfo [I]. mimeType, format) = 0) <br/>{< br/> * pCLSID = pImageCodecInfo [I]. clsid; <br/> free (pImageCodecInfo); <br/> return TRUE; <br/>}< br/> free (pImageCodecInfo ); <br/> return FALSE; <br/>}

 

The above method is applicable when you know the BMP bitmap file, while converting from IPicture to jpg bitmap requires a slight change

 

LONG ExportShowPic (LONG nPicIndex, LPCTSTR strSavePath) // nPicIndex is the index of the IPICTURE array object, <br/> {// strSavePath is the jpg image storage path <br/> if (m_pIPicture [nPicIndex] = NULL) <br/>{< br/> return FALSE; <br/>}< br/> BOOL bResult = FALSE; <br/> // int iBmpSize = cbfBmp. getLength (); <br/> HGLOBAL hMemBmp = GlobalAlloc (GMEM_MOVEABLE, 0); <br/> if (hMemBmp = NULL) return FALSE; <br/> IStream * pStmBmp = NULL; <br/> C ReateStreamOnHGlobal (hMemBmp, FALSE, & pStmBmp); <br/> if (pStmBmp = NULL) <br/>{< br/> GlobalFree (hMemBmp ); <br/> return FALSE; <br/>}< br/> // BYTE * pbyBmp = (BYTE *) GlobalLock (hMemBmp); <br/> // cbfBmp. seekToBegin (); <br/> // cbfBmp. read (pbyBmp, iBmpSize); <br/> long OutStream = 0; <br/> m_pIPicture [nPicIndex]-> SaveAsFile (pStmBmp, TRUE, & OutStream ); // Copy Data Stream </p> <p> Image * imImage = NUL L; <br/> imImage = Image: FromStream (pStmBmp, FALSE); <br/> if (imImage = NULL) <br/>{< br/> GlobalUnlock (hMemBmp); <br/> GlobalFree (hMemBmp); <br/> return FALSE; <br/>}< br/> USES_CONVERSION; <br/> CLSID clImageClsid; <br/> GetImageCLSID (_ T ("image/jpeg"), & clImageClsid ); </p> <p> HGLOBAL hMemImage = GlobalAlloc (GMEM_MOVEABLE, 0); <br/> if (hMemImage = NULL) <br/>{< br/> pStmBmp-> Release (); <br /> GlobalUnlock (hMemBmp); <br/> GlobalFree (hMemBmp); <br/> if (imImage! = NULL) delete imImage; <br/> return FALSE; <br/>}< br/> IStream * pStmImage = NULL; <br/> CreateStreamOnHGlobal (hMemImage, TRUE, & pStmImage); <br/> if (pStmImage = NULL) <br/>{< br/> pStmBmp-> Release (); <br/> GlobalUnlock (hMemBmp ); <br/> GlobalFree (hMemBmp); <br/> GlobalFree (hMemImage); <br/> if (imImage! = NULL) delete imImage; <br/> return FALSE; <br/>}< br/> imImage-> Save (pStmImage, & clImageClsid ); <br/> if (pStmImage = NULL) <br/>{< br/> pStmBmp-> Release (); <br/> pStmImage-> Release (); <br/> GlobalUnlock (hMemBmp); <br/> GlobalFree (hMemImage); <br/> if (imImage! = NULL) delete imImage; <br/> return FALSE; <br/>}< br/> LARGE_INTEGER liBegin = {0}; <br/> pStmImage-> Seek (liBegin, STREAM_SEEK_SET, NULL); <br/> BYTE * pbyImage = (BYTE *) GlobalLock (hMemImage); <br/> // cbfImage. seekToBegin (); <br/> // cbfImage. write (pbyImage, GlobalSize (hMemImage); <br/> CFile fileJpg; <br/> if (fileJpg. open (strSavePath, CFile: modeCreate | CFile: modeWrite) <br/>{< br/> fileJpg. SeekToBegin (); <br/> fileJpg. Write (pbyImage, GlobalSize (hMemImage); <br/>}< br/> if (imImage! = NULL) delete imImage; <br/> pStmBmp-> Release (); <br/> pStmImage-> Release (); <br/> GlobalUnlock (hMemBmp ); <br/> GlobalUnlock (hMemImage); <br/> GlobalFree (hMemBmp); <br/> GlobalFree (hMemImage); </p> <p> bResult = TRUE; </p> <p> return TRUE; <br/>}