使用IPicture介面讀取和顯示BMP,GIF,JPG,ICO,EMF,WMF影像 (轉)[@more@]

問題的起源

很久以來，我都被一個問題困擾。關於中顯示影像的問題，我在上搜尋了很長時間，找到了無數的解決方案，比如分析格式,直接讀取檔案的;用的(ImgEdit);以及不知道內部實現方法的庫（ImageLoad）。而我找到的方法大都不容易使用，特別是那些直接按位讀取影像的。很多時候我不得不為每種檔案格式寫一段程式碼。

目前我的解決方案

在使用了多種圖形顯示方案之後，我決定使用提供的IPicture介面來顯示影像。由於MFC的CPictureHolder類是這個介面的一個封裝，而且自帶了從影像控制程式碼讀入圖形的功能，所以我的工作以CPictureHolder類為基礎。要是你不喜歡MFC的話，你可以把CPictureHolder類的程式碼從MFC的裡面分離出來單獨使用。

CPictureHolder類的設計目的是實現控制元件的Picture屬性，允許在控制元件中顯示影像。作為預設的Picture屬性，開發者可以指定一個點陣圖(Bitmap)，圖示(Icon)，或者圖元檔案(Metafile)來顯示。雖然微軟的文件中並未說明支援JPEG格式的影像，但是經過我的測試，在98以上，以及中，它實際上是支援JPEG格式的，根據微軟的文件，支援的影像格式有BMP,DIB,WMF，ICO。筆者並未測試其他影像格式是否被支援，例如PNG、GIF、PCX等等，有興趣的讀者可以去自己測試一下。(據111222的文件/develop/read_article.?id=10632">http://www.csdn.net/develop/read_article.asp?id=10632，也支援GIF格式)

由於CPictureHolder類並未實現從檔案/資源/讀入影像，使用起來很不方便，所以我擴充套件了這個類以支援上述功能。部分工作基於Dr. Yovav Gad, （to:s@SuperMain.com">Sources@SuperMain.com ，）和的程式碼。

要使用CPictureHolder類，必須先包含afxctl.h

原始碼

#include
class CPicture:public CPictureHolder
{
public:
 BOOL Load(CString ilePathName);//從檔案讀取影像
 BOOL Load(HINSTANCE hInstance,LPCTSTR lpszResourceName, LPCSTR ResourceType);//從資源讀取影像
 BOOL LoadPictureData(BYTE* pBuffer, int nSize);//從記憶體讀取影像
 BOOL SaveAsBitmap(CString sFilePathName);//寫入到BMP檔案
 void Render(CDC* pDC, LPRECT pDrawRect/*目標矩形，單位是邏輯座標單位*/, LPRECT

pSrcRect=NULL/*來源矩形，單位是0.01毫米,如果為空，則拉伸整個影像到目標矩形*/,LPCRECT prcWBounds=NULL/*圖元檔案專用，繫結矩形*/);//在給定的DC上畫圖，
 CPicture();
 virtual ~CPicture();
 void UnloadPicture();//釋放影像，作用同CPictureHolder::~CPictureHolder()
public:
 LONG  get_Height(); // 以0.01毫米為單位的影像高度
 LONG  get_Width();  // 以0.01毫米為單位的影像寬度
};

//-----------------------------------------------------------------------------
// Does:  Free The Allocated Memory That Holdes The IPicture Interface Data
// ~~~~  And Clear Picture Information
//
// Note:  This Might Also Be Useful If U Only Need To Show The Picture Once
// ~~~~~  Or If U Copy The Picture To The Device Context, So It Can Still
//  Remain On Screen - But IPicture Data Is Not Needed No More
//
//-----------------------------------------------------------------------------
void CPicture::UnloadPicture()
//=============================================================================
{
 if(m_pPict != NULL){
 m_pPict->Release();
 m_pPict = NULL;
 }
}
//-----------------------------------------------------------------------------
// Does:  Open a Resource And Load It Into IPicture (Interface)
// ~~~~  (.BMP .DIB .EMF .GIF .ICO .JPG .WMF)
//
// Note:  When Adding a Bitmap Resource It Would Automatically Show On "Bitmap"
// ~~~~  This NOT Good Coz We Need To Load It From a Custom Resource "BMP"
//  To Add a Custom Rresource: Import Resource -> Open As -> Custom
//  (Both .BMP And .DIB Should Be Found Under "BMP")
//
// InPut:  ResourceName - As a UINT Defined (Example: IDR_PICTURE_RESOURCE)
// ~~~~~  ResourceType - Type Name (Example: "JPG")
//
// OutPut: TRUE If Succeeded...
// ~~~~~~
//-----------------------------------------------------------------------------
BOOL CPicture::Load(HINSTANCE hInstance,LPCTSTR lpszResourceName, LPCSTR ResourceType)
//=============================================================================
{
 HGLOBAL hGlobal = NULL;
 HRSRC hSource = NULL;
 LPVOID lpVoid  = NULL;
 int nSize  = 0;
 BOOL bResult=FALSE;
 if(m_pPict != NULL) UnloadPicture(); // Important - Avoid Leaks...

 hSource = FindResource(hInstance, lpszResourceName, ResourceType);

 if(hSource == NULL)
 {
 HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd;
 MessageBoxEx(hWnd, "FindResource() Failedt", ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH);
 return(FALSE);
 }

 hGlobal = LoadResource(hInstance, hSource);
 if(hGlobal == NULL)
 {
 HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd;
 MessageBoxEx(hWnd, "LoadResource() Failedt", ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH);
 return(FALSE);
 }

 lpVoid = LockResource(hGlobal);
 if(lpVoid == NULL)
 {
 HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd;
 MessageBoxEx(hWnd, "LockResource() Failedt", ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH);
 return(FALSE);
 }

 nSize = (UINT)SizeofResource(hInstance, hSource);
 if(LoadPictureData((BYTE*)hGlobal, nSize)) bResult = TRUE;

 UnlockResource(hGlobal); // 16Bit Windows Needs This
 FreeResource(hGlobal); // 16Bit Windows Needs This (32Bit - Automatic Release)
 return(bResult);
}

//-----------------------------------------------------------------------------
// Does:  Open a File And Load It Into IPicture (Interface)
// ~~~~  (.BMP .DIB .EMF .GIF .ICO .JPG .WMF)
//
// InPut:  sFilePathName - Path And FileName Target To Save
// ~~~~~ 
//
// OutPut: TRUE If Succeeded...
// ~~~~~~
//-----------------------------------------------------------------------------
BOOL CPicture::Load(CString sFilePathName)
//=============================================================================
{
 if(!PathFileExists(sFilePathName))return FALSE;
 BOOL bResult = FALSE;
 CFile PictureFile;
 CFileException e;
 int nSize = 0;

 if(m_pPict != NULL) UnloadPicture(); // Important - Avoid Leaks...

 if(PictureFile.Open(sFilePathName, CFile::modeRead | CFile::typeBinary, &e))
 {
 nSize = PictureFile.GetLength();
 BYTE* pBuffer = new BYTE[nSize];
 
 if(PictureFile.Read(pBuffer, nSize) > 0)
 {
 if(LoadPictureData(pBuffer, nSize)) bResult = TRUE;
 }

 PictureFile.Close();
 delete [] pBuffer;
 }
 else // Open Failed...
 {
 TCHAR szCause[255];
 e.GetErrorMessage(szCause, 255, NULL);
 HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd;
 MessageBoxEx(hWnd, szCause, ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH);
 bResult = FALSE;
 }
 return(bResult);
}

//-----------------------------------------------------------------------------
// Does:  Read The Picture Data From a Source (File / Resource)
// ~~~~  And Load It Into The Current IPicture In Use
//
// InPut:  Buffer Of Data Source (File / Resource) And Its Size
// ~~~~~ 
//
// OutPut: Feed The IPicture Object With The Picture Data
// ~~~~~~  (Use Draw Functions To Show It On a Device Context)
//  TRUE If Succeeded...
//-----------------------------------------------------------------------------
BOOL CPicture::LoadPictureData(BYTE *pBuffer, int nSize)
//=============================================================================
{
 BOOL bResult = FALSE;
 HGLOBAL hGlobal = GlobalAlloc(GMEM_MOVEABLE, nSize);

 if(hGlobal == NULL)
 {
 HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd;
 MessageBoxEx(hWnd, "Can not allocate enough memoryt", ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH);
 return(FALSE);
 }

 void* pData = GlobalLock(hGlobal);
 memcpy(pData, pBuffer, 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_pPict)) == E_NOINTERFACE)
 {
 HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd;
 MessageBoxEx(hWnd, "IPicture interface is not supportedt", ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH);
 return(FALSE);
 }
 else // S_OK
 {
 pStream->Release();
 pStream = NULL;
 bResult = TRUE;
 
 }
 }

 FreeResource(hGlobal); // 16Bit Windows Needs This (32Bit - Automatic Release)

 return(bResult);
}

//-----------------------------------------------------------------------------
// Does:  Draw The Loaded Picture Direct To The Client DC
// ~~~~
//
// Note:  Bigger OR Smaller Dimentions Than The Original Picture Size
// ~~~~  Will Draw The Picture Streached To Its New Given NEW Dimentions...
//
// InPut:  pDC - Given DC To Draw On
// ~~~~~  pSrcRect- Dimentions Of The Picture To Draw From(As a Rectangle)
// DrawRect - Dimentions Of The Picture To Draw To(As a Rectangle)
// OutPut: TRUE If Succeeded...
// ~~~~~~
//-----------------------------------------------------------------------------
//=============================================================================

void CPicture::Render(CDC* pDC, LPRECT pDrawRect, LPRECT pSrcRect/*=NULL*/,LPCRECT prcWBounds/*=NULL*/)
{
  if (pDC == NULL || m_pPict == NULL) return ;
 
 CRect recrDest(pDrawRect);

  long Width  = 0;
  long Height = 0;
  m_pPict->get_Width(&Width);
  m_pPict->get_Height(&Height);

 CRect SrcRect(0,0,Width,Height);

 if(pSrcRect){
 SrcRect=*pSrcRect;
 }
 CRect DrawRect(pDrawRect);
  HRESULT hrP = NULL;

  hrP = m_pPict->Render(pDC->m_hDC,
  DrawRect.left,  // Left
  DrawRect.top,  // Top
  DrawRect.Width(), // Right
  DrawRect.Height(), // Bottom
  SrcRect.left,
  SrcRect.top,
  SrcRect.Width(),
  SrcRect.Height(),
  prcWBounds);

  if (SUCCEEDED(hrP)) return;
 AfxThrowMemoryException();
  return;
}//-----------------------------------------------------------------------------
// Does:  Saves The Picture That Is Stored In The IPicture Object As a Bitmap
// ~~~~  (Converts From Any Known Picture Type To a Bitmap / Icon File)
//
// InPut:  sFilePathName - Path And FileName Target To Save
// ~~~~~
//
// OutPut: TRUE If Succeeded...
// ~~~~~~
//-----------------------------------------------------------------------------
BOOL CPicture::SaveAsBitmap(CString sFilePathName)
//=============================================================================
{
 BOOL bResult = FALSE;
 ILockBytes *Buffer = 0;
 IStorage  *pStorage = 0;
 IStream  *FileStream = 0;
 BYTE  *BufferBytes;
 STATSTG BytesStatistics;
 D OutData;
 long OutStream;
 CFile BitmapFile; CFileException e;
 double SkipFloat = 0;
 DWORD ByteSk= 0;
 _ULARGE_INTEGER RealData;

 CreateILockBytesOnHGlobal(NULL, TRUE, &Buffer); // Create ILockBytes Buffer

 HRESULT hr = ::StgCreateDocfileOnILockBytes(Buffer,
  STGM_SHARE_EXCLUSIVE | STGM_CREATE | STGM_READWRITE, 0, &pStorage);

 hr = pStorage->CreateStream(L"PICTURE",
  STGM_SHARE_EXCLUSIVE | STGM_CREATE | STGM_READWRITE, 0, 0, &FileStream);

 m_pPict->SaveAsFile(FileStream, TRUE, &OutStream); // Copy Data Stream
 FileStream->Release();
 pStorage->Release();
 Buffer->Flush();

 // Get Statistics For Final Size Of Byte Array
 Buffer->Stat(&BytesStatistics, STATFLAG_NONAME);

 // Cut UnNeeded Data Coming From SaveAsFile() (Leave Only "Pure" Picture Data)
 SkipFloat = (double(OutStream) / 512); // Must Be In a 512 Blocks...
 if(SkipFloat > DWORD(SkipFloat)) ByteSkip = (DWORD)SkipFloat + 1;
 else ByteSkip = (DWORD)SkipFloat;
 ByteSkip = ByteSkip * 512; // Must Be In a 512 Blocks...
 
 // Find Difference Between The Two Values
 ByteSkip = (DWORD)(BytesStatistics.cbSize.QuadPart - ByteSkip);

 // Allocate Only The "Pure" Picture Data
 RealData.LowPart = 0;
 RealData.HighPart = 0;
 RealData.QuadPart = ByteSkip;
 BufferBytes = (BYTE*)malloc(OutStream);
 if(BufferBytes == NULL)
 {
 Buffer->Release();
 HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd;
 MessageBoxEx(hWnd, "Can not allocate enough memoryt", ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH);
 }

 Buffer->ReadAt(RealData, BufferBytes, OutStream, &OutData);

 if(BitmapFile.Open(sFilePathName, CFile::typeBinary | CFile::modeCreate | CFile::modeWrite, &e))
 {
 BitmapFile.Write(BufferBytes, OutData);
 BitmapFile.Close();
 bResult = TRUE;
 }
 else // Write File Failed...
 {
 TCHAR szCause[255];
 e.GetErrorMessage(szCause, 255, NULL);
 HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd;
 MessageBoxEx(hWnd, szCause, ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH);
 bResult = FALSE;
 }
 
 Buffer->Release();
 free(BufferBytes);

 return(bResult);
}

LONG  CPicture::get_Height()
{
 LONG  nHeight = 0;

 if (m_pPict != NULL)
 {
 m_pPict->get_Height(&nHeight);
 }

 return nHeight;
}
LONG  CPicture::get_Width()
{
 LONG  nWidth = 0;

 if (m_pPict != NULL)
 {
 m_pPict->get_Width(&nWidth);
 }

 return nWidth;

}