使用IPicture接口读取和显示BMP,GIF,JPG,ICO,EMF,WMF图像
导读：
使用IPicture接口读取和显示BMP,GIF,JPG,ICO,EMF,WMF图像 (转)
问题的起源
很久以来，我都被一个问题困扰。关于程序中显示图像的问题，我在网络上搜索了很长时间，找到了无数的解决方案，比如分析文件格式,直接读取文件的;用控件的(ImgEdit);以及不知道内部实现方法的库（ImageLoad）。而我找到的方法大都不容易使用，特别是那些直接按位读取图像的。很多时候我不得不为每种文件格式写一段代码。
目前我的解决方案
在使用了多种图形显示方案之后，我决定使用微软提供的IPicture接口来显示图像。由于MFC的CPictureHolder类是这个接口的一个封装，而且自带了从图像句柄读入图形的功能，所以我的工作以CPictureHolder类为基础。要是你不喜欢MFC的话，你可以把CPictureHolder类的代码从MFC的源代码里面分离出来单独使用。
CPictureHolder类的设计目的是实现ActiveX控件的Picture属性，允许用户在控件中显示图像。作为默认的Picture属性，开发者可以指定一个位图(Bitmap)，图标(Icon)，或者图元文件(Metafile)来显示。虽然微软的文档中并未说明支持JPEG格式的图像，但是经过我的测试，在windows98以上，以及Windows2000中，它实际上是支持JPEG格式的，根据微软的文档，支持的图像格式有BMP,DIB,WMF，ICO。笔者并未测试其他图像格式是否被支持，例如PNG、GIF、PCX等等，有兴趣的读者可以去自己测试一下。(据111222的文档.NET/develop/read_article.ASP?id=10632">http://www.csdn.net/develop/read_article.asp?id=10632，也支持GIF格式)
由于CPictureHolder类并未实现从文件/资源/内存读入图像，使用起来很不方便，所以我扩展了这个类以支持上述功能。部分工作基于Dr. Yovav Gad, （Mailto:[email protected]">[email protected]，www.SuperMain.com）和http://www.thecodeproject.com/bitmap/cpicture.asp的代码。
要使用CPictureHolder类，必须先包含afxctl.h
源代码
- #include
- class CPicture: public CPictureHolder
- {
- public :
- BOOL Load(CString sfilePathName); //从文件读取图像
- BOOL Load( HINSTANCE hInstance, LPCTSTR lpszResourceName, LPCSTR ResourceType); //从资源读取图像
- BOOL LoadPictureData( BYTE * pBuffer, int nSize); //从内存读取图像
- BOOL SaveAsBitmap(CString sFilePathName); //写入到BMP文件
- void Render(CDC* pDC, LPRECT pDrawRect /*目标矩形，单位是逻辑坐标单位*/ , LPRECT
- pSrcRect=NULL /*来源矩形，单位是0.01毫米,如果为空，则拉伸整个图像到目标矩形*/ ,LPCRECT prcWBounds=NULL /*图元文件专用，绑定矩形*/ ); //在给定的DC上画图，
- CPicture();
- virtual ~CPicture();
- void UnloadPicture(); //释放图像，作用同CPictureHolder::~CPictureHolder()
- public :
- LONG get_Height(); // 以0.01毫米为单位的图像高度
- LONG get_Width(); // 以0.01毫米为单位的图像宽度
- };
- //-----------------------------------------------------------------------------
- // 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 objectIn 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;
- Dword OutData;
- long OutStream;
- CFile BitmapFile; CFileException e;
- double SkipFloat = 0;
- DWORD ByteSkip= 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;
- }