怎样显示jpg图像？

Question

// Picture.cpp: implementation of the CPicture class.
//
//////////////////////////////////////////////////////////////////////#include "stdafx.h"
#include "Picture.h"#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////CPicture::CPicture()
{
m_pPicture = NULL;
}CPicture::~CPicture()
{
UnLoad();
}bool CPicture::Load(CString sResourceType, CString sResource)
{
bool bResult = false; if (m_pPicture != NULL)
UnLoad(); if (m_pPicture == NULL)
{
BYTE* pBuff = NULL;
int nSize = 0;
if (GetResource(sResource.GetBuffer(0), sResourceType.GetBuffer(0), pBuff, nSize))
{
if (nSize > 0)
{
pBuff = new BYTE[nSize]; if (GetResource(sResource.GetBuffer(0), sResourceType.GetBuffer(0), pBuff, nSize))
{
if (LoadFromBuffer(pBuff, nSize))
bResult = true;
} delete [] pBuff;
}
}
}
return bResult;
}bool CPicture::Load(CString sFileName)
{
bool bResult = false; if (m_pPicture != NULL)
UnLoad(); if (m_pPicture == NULL)
{
CFile cFile;
CFileException e; if (cFile.Open(sFileName, CFile::modeRead | CFile::typeBinary, &e))
{
BYTE* pBuff = new BYTE[cFile.GetLength()]; if (cFile.Read(pBuff, cFile.GetLength()) > 0)
{
if (LoadFromBuffer(pBuff, cFile.GetLength()))
bResult = true;
} delete [] pBuff;
}
}
return bResult;
}void CPicture::UnLoad()
{
if (m_pPicture != NULL)
{
m_pPicture->Release();
m_pPicture = NULL;
}
}bool CPicture::Draw(CDC* pDC)
{
if (m_pPicture != NULL)
{
long hmWidth;
long hmHeight;
m_pPicture->get_Width(&hmWidth);
m_pPicture->get_Height(&hmHeight); int nWidth = MulDiv(hmWidth, pDC->GetDeviceCaps(LOGPIXELSX), HIMETRIC_INCH);
int nHeight = MulDiv(hmHeight, pDC->GetDeviceCaps(LOGPIXELSY), HIMETRIC_INCH);

return Draw(pDC, 0, 0, nWidth, nHeight);
}
return false;
}bool CPicture::Draw(CDC* pDC, CPoint Pos)
{
if (m_pPicture != NULL)
{
long hmWidth;
long hmHeight;
m_pPicture->get_Width(&hmWidth);
m_pPicture->get_Height(&hmHeight); int nWidth = MulDiv(hmWidth, pDC->GetDeviceCaps(LOGPIXELSX), HIMETRIC_INCH);
int nHeight = MulDiv(hmHeight, pDC->GetDeviceCaps(LOGPIXELSY), HIMETRIC_INCH);

return Draw(pDC, Pos.x, Pos.y, nWidth, nHeight);
}
return false;
}bool CPicture::Draw(CDC* pDC, CPoint Pos, CSize Size)
{
if (m_pPicture != NULL)
{
long hmWidth;
long hmHeight;
m_pPicture->get_Width(&hmWidth);
m_pPicture->get_Height(&hmHeight); int nWidth = Size.cx;
int nHeight = Size.cy;

return Draw(pDC, Pos.x, Pos.y, nWidth, nHeight);
}
return false;
}bool CPicture::Draw(CDC* pDC, double nSizeRatio)
{
if (m_pPicture != NULL)
{
long hmWidth;
long hmHeight;
m_pPicture->get_Width(&hmWidth);
m_pPicture->get_Height(&hmHeight); int nWidth = int(MulDiv(hmWidth, pDC->GetDeviceCaps(LOGPIXELSX), HIMETRIC_INCH) * nSizeRatio);
int nHeight = int(MulDiv(hmHeight, pDC->GetDeviceCaps(LOGPIXELSY), HIMETRIC_INCH) * nSizeRatio);

return Draw(pDC, 0, 0, nWidth, nHeight);
}
return false;
}bool CPicture::Draw(CDC* pDC, CPoint Pos, double nSizeRatio)
{
if (m_pPicture != NULL)
{
long hmWidth;
long hmHeight;
m_pPicture->get_Width(&hmWidth);
m_pPicture->get_Height(&hmHeight); int nWidth = int(MulDiv(hmWidth, pDC->GetDeviceCaps(LOGPIXELSX), HIMETRIC_INCH) * nSizeRatio);
int nHeight = int(MulDiv(hmHeight, pDC->GetDeviceCaps(LOGPIXELSY), HIMETRIC_INCH) * nSizeRatio);

return Draw(pDC, Pos.x, Pos.y, nWidth, nHeight);
}
return false;
}bool CPicture::Draw(CDC* pDC, int x, int y, int cx, int cy)
{
long hmWidth;
long hmHeight;
m_pPicture->get_Width(&hmWidth);
m_pPicture->get_Height(&hmHeight); if (m_pPicture->Render(pDC->m_hDC, x, y, cx, cy, 0, hmHeight, hmWidth, -hmHeight, NULL) == S_OK)
return true; return false;
}bool CPicture::LoadFromBuffer(BYTE* pBuff, int nSize)
{
bool bResult = false; HGLOBAL hGlobal = GlobalAlloc(GMEM_MOVEABLE, nSize);
void* pData = GlobalLock(hGlobal);
memcpy(pData, pBuff, nSize);
GlobalUnlock(hGlobal); IStream* pStream = NULL; if (CreateStreamOnHGlobal(hGlobal, TRUE, &pStream) == S_OK)
{
HRESULT hr;
if ((hr = OleLoadPicture(pStream, nSize, FALSE, IID_IPicture, (LPVOID *)&m_pPicture)) == S_OK)
bResult = true;

pStream->Release();
} return bResult;
}bool CPicture::GetResource(LPSTR lpName, LPSTR lpType, void* pResource, int& nBufSize)
{ 
HRSRC hResInfo;
HANDLE hRes;
HMODULE hInst = NULL; 
LPSTR lpRes = NULL; 
int nLen = 0;
bool bResult = FALSE; // Find the resource
hResInfo = FindResource(hInst, lpName, lpType); if (hResInfo == NULL) 
return false; // Load the resource
hRes = LoadResource(hInst, hResInfo); if (hRes == NULL) 
return false; // Lock the resource
lpRes = (char*)LockResource(hRes); if (lpRes != NULL)
{ 
if (pResource == NULL)
{
nBufSize = SizeofResource(hInst, hResInfo);
bResult = true;
}
else
{
if (nBufSize >= (int)SizeofResource(hInst, hResInfo))
{
memcpy(pResource, lpRes, nBufSize);
bResult = true;
}
}  UnlockResource(hRes);  
} // Free the resource
FreeResource(hRes); return bResult;
}CSize CPicture::GetSize(CDC* pDC)
{
CSize rcResult = CSize(0,0);

if (m_pPicture != NULL)
{
long hmWidth;
long hmHeight;
m_pPicture->get_Width(&hmWidth);
m_pPicture->get_Height(&hmHeight); rcResult.cx = MulDiv(hmWidth, pDC->GetDeviceCaps(LOGPIXELSX), HIMETRIC_INCH);
rcResult.cy = MulDiv(hmHeight, pDC->GetDeviceCaps(LOGPIXELSY), HIMETRIC_INCH);
} return rcResult;
}

Answer 1

// Picture.h: interface for the CPicture class.
//
//////////////////////////////////////////////////////////////////////#if !defined(AFX_PICTURE_H__6098A4C3_D6D5_4711_BC7B_1595F459B480__INCLUDED_)
#define AFX_PICTURE_H__6098A4C3_D6D5_4711_BC7B_1595F459B480__INCLUDED_#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000class CPicture  
{
public:
CPicture();
virtual ~CPicture(); bool Load(CString sResourceType, CString sResource);
bool Load(CString sFileName);
bool Draw(CDC* pDC);
bool Draw(CDC* pDC, CPoint Pos);
bool Draw(CDC* pDC, CPoint Pos, CSize Size);
bool Draw(CDC* pDC, double nSizeRatio);
bool Draw(CDC* pDC, CPoint Pos, double nSizeRatio);
CSize GetSize(CDC* pDC);
private:
static bool GetResource(LPSTR lpName, LPSTR lpType, void* pResource, int& nBufSize);
void UnLoad();
bool LoadFromBuffer(BYTE* pBuff, int nSize);
bool Draw(CDC* pDC, int x, int y, int cx, int cy);
IPicture* m_pPicture;
enum
{
HIMETRIC_INCH = 2540
};
};#endif // !defined(AFX_PICTURE_H__6098A4C3_D6D5_4711_BC7B_1595F459B480__INCLUDED_)

Answer 2

CRect rect;
CDC *pDC ;
//GetDlgItem(IDC_BMP)->GetClientRect(&rect);
CWnd *pWnd = GetDlgItem(IDC_BMP);
pWnd->GetWindowRect(rect);
pDC = pWnd->GetDC();
this->ScreenToClient(&rect);
pic.Draw(pDC,CPoint(0,0),CSize(rect.Width(),rect.Height()));