ShowImagePreview.rar

#include "stdafx.h" #include "cPic.h" /************************************************************************** * * * " T H E _ F I L E _ C L A S S " * * * **************************************************************************/ /* WHY THIS CLASS? JUST TO MAKE THINGS EASIER WHEN READING THE IMAGE FILE */ //constructor _FILE_::_FILE_() { m_File = NULL; } //destructor ! _FILE_::~_FILE_() { // this->Close(); } //opens a file either for reading or writing BOOL _FILE_::OpenA(char * FileName ,FILE_OPENMODE Open_Mode) { switch (Open_Mode) { case OFM_READ: m_File = fopen(FileName,"rb"); break; case OFM_WRITE: m_File = fopen(FileName,"wb"); break; } if(!m_File) return FALSE; return TRUE; } BOOL _FILE_::OpenW(WCHAR * FileName ,FILE_OPENMODE Open_Mode) { switch (Open_Mode) { case OFM_READ: m_File =_wfsopen(FileName,L"rb",_SH_DENYNO); break; case OFM_WRITE: m_File = _wfsopen(FileName,L"wb",_SH_DENYNO); break; } if(!m_File) return FALSE; return TRUE; } //Reads data from the file stream. BOOL _FILE_::Read(VOID * zBuffer,DWORD cSize) { if(fread(zBuffer,sizeof(BYTE),cSize,m_File) < cSize) return FALSE; return TRUE; } //Writes data to the file stream. BOOL _FILE_::Write(VOID * zBuffer,DWORD cSize) { if(fwrite(zBuffer,sizeof(BYTE),cSize,m_File) < cSize) return FALSE; return TRUE; } //Gets the File Size LONG _FILE_::GetSize(VOID) { long t_location = ftell(m_File); fseek(this->m_File,0,SEEK_END); long f_size = ftell(this->m_File ); fseek(this->m_File ,t_location,SEEK_SET); return f_size; } //Closes the File VOID _FILE_::Close(VOID) { if(m_File) { fclose(this->m_File); this->m_File = NULL; } return; } /************************************************************************** * * * " T H E _ P I C T U R E _ C L A S S " * * * **************************************************************************/ /* A CLASS FOR READING IMAGE FILES LIKE JPG,BMP,WMF,GIF...LIKE THE ONE IN VISUAL BASIC AND DRAWING THEM AS WELL */ //constructor _PICTURE_::_PICTURE_() { m_pic = NULL; hGlobal = NULL; } //destructor _PICTURE_::~_PICTURE_() { this->FreePicture(); } /* OUR MAIN FUNCTION */ HBITMAP _PICTURE_::LoadPictureA(char *FileName) { _FILE_ cFile; //the image file //if we couldn't open the image file then we should get out of here if(!cFile.OpenA(FileName,OFM_READ)) return NULL; //we must know exactly the buffer size to allocate //in order to read the image in it //so get the image file size long nSize = cFile.GetSize(); //allocate enough memory to hold the image //it must be allocated using GlobalAlloc //otherwise it will fail...try using new or malloc and you'll see!!! hGlobal = GlobalAlloc(GMEM_MOVEABLE,nSize); //get pointer to first byte void* pData = GlobalLock(hGlobal); //read the file in the prev allocated memory if(!cFile.Read(pData,nSize)) return NULL;; //we don't need the file any more so close it cFile.Close(); GlobalUnlock(hGlobal); IStream* pStream = NULL; //ole routines.... //creates a stream from our handle //don't know why and how? if (CreateStreamOnHGlobal(hGlobal, TRUE, &pStream) != S_OK) return NULL; HRESULT hr; //aha..now let ole reads the image and load it for us if ((hr = OleLoadPicture(pStream, nSize, FALSE, IID_IPicture, (LPVOID *)&this->m_pic)) != S_OK) return NULL; HBITMAP hbmp = NULL; //return an HBITMAP to our image like the LoadImage function does //we might need the handle this->m_pic->get_Handle((OLE_HANDLE *) &hbmp); return hbmp; } HBITMAP _PICTURE_::LoadPictureW(WCHAR *FileName) { _FILE_ cFile; //the image file //if we couldn't open the image file then we should get out of here if(!cFile.Open(FileName,OFM_READ)) return NULL; //we must know exactly the buffer size to allocate //in order to read the image in it //so get the image file size long nSize = cFile.GetSize(); //allocate enough memory to hold the image //it must be allocated using GlobalAlloc //otherwise it will fail...try using new or malloc and you'll see!!! hGlobal = GlobalAlloc(GMEM_MOVEABLE,nSize); //get pointer to first byte void* pData = GlobalLock(hGlobal); //read the file in the prev allocated memory if(!cFile.Read(pData,nSize)) return NULL;; //we don't need the file any more so close it cFile.Close(); GlobalUnlock(hGlobal); IStream* pStream = NULL; //ole routines.... //creates a stream from our handle //don't know why and how? if (CreateStreamOnHGlobal(hGlobal, TRUE, &pStream) != S_OK) return NULL; HRESULT hr; //aha..now let ole reads the image and load it for us if ((hr = OleLoadPicture(pStream, nSize, FALSE, IID_IPicture, (LPVOID *)&this->m_pic)) != S_OK) return NULL; HBITMAP hbmp = NULL; //return an HBITMAP to our image like the LoadImage function does //we might need the handle this->m_pic->get_Handle((OLE_HANDLE *) &hbmp); return hbmp; } //an overloaded version of the above to draw the picture //as well in a given DC HBITMAP _PICTURE_::LoadPictureA(char *FileName,HDC hdc) { HBITMAP hbmp = this->LoadPictureA(FileName); this->DrawPicture(hdc,0,0,this->_GetWidth(),_GetHeight()); return hbmp; } HBITMAP _PICTURE_::LoadPictureW(WCHAR *FileName,HDC hdc) { HBITMAP hbmp = this->LoadPicture(FileName); this->DrawPicture(hdc,0,0,this->_GetWidth(),_GetHeight()); return hbmp; } //returns the width of the loaded image DWORD _PICTURE_::_GetWidth(VOID) { if(! m_pic) return 0; OLE_XSIZE_HIMETRIC pWidth; m_pic->get_Width(&pWidth); HDC tDC = CreateCompatibleDC(0); int nWidth = MulDiv(pWidth,GetDeviceCaps(tDC,LOGPIXELSX), HIMETRIC_INCH); DeleteDC(tDC); return (DWORD) nWidth; } //returns the height of the loaded image DWORD _PICTURE_::_GetHeight(VOID) { if(! m_pic) return 0; OLE_YSIZE_HIMETRIC pHeight; m_pic->get_Height(&pHeight); HDC tDC = CreateCompatibleDC(0); int nHeight = MulDiv(pHeight,GetDeviceCaps(tDC,LOGPIXELSY), HIMETRIC_INCH); DeleteDC(tDC); return (DWORD) nHeight; } //returns the current DC of the loaded image HDC _PICTURE_::_GetDC(VOID) { if(! m_pic) return NULL; HDC pDC ; m_pic->get_CurDC(&pDC); return pDC; } //returns the Handle of the loaded image(HBITMAP) HBITMAP _PICTURE_::_GetHandle( VOID ) { if(! m_pic) return NULL; HBITMAP hbmp; m_pic->get_Handle((OLE_HANDLE *) &hbmp); return hbmp; } //Draws the image in a specified DC..with given dimensions //specify -1 for width and height if you like to draw //with original dimensions BOOL _PICTURE_::DrawPicture(HDC hdc,long x,long y,long cx,long cy) { if(! m_pic) return FALSE; LONG pHeight,pWidth; if(cx == -1) cx = this->_GetWidth(); if(cy == -1) cy = this->_GetHeight(); m_pic->get_Width(&pWidth); m_pic->get_Height(&pHeight); if (m_pic->Render(hdc, x, y, cx, cy,0, pHeight, pWidth,-pHeight, NULL) != S_OK) return FALSE ; return TRUE; } //Cleans up VOID _PICTURE_::FreePicture(VOID) { if (m_pic) { m_pic->Release(); m_pic = NULL; } if (hGlobal) { GlobalFree(hGlobal); hGlobal = NULL; } }