Jpegfile.h
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上传日期:2022-05-11
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文件大小:7k
源码类别:
网络截获/分析
开发平台:
Visual C++
- ////////////////////////////////////////////////////////////
- //
- // JpegFile - A C++ class to allow reading and writing of
- // RGB and Grayscale JPEG images. (actually, it reads all forms
- // that the JPEG lib will decode into RGB or grayscale) and
- // writes only RGB and Grayscale.
- //
- // It is based on a Win32 compilation of the IJG V.6a code.
- //
- // This will only work on 32-bit Windows systems. I have only
- // tried this with Win 95, VC++ 4.1.
- //
- // This class Copyright 1997, Chris Losinger
- // This is free to use and modify provided my name is included.
- //
- // Comments:
- // Thanks to Robert Johnson for discovering a DWORD-alignment bug
- // Thanks to Lee Bode for catching a bug in CMfcappView::OnFileGetdimensionsjpg()
- //
- ////////////////////////////////////////////////////////////
- //
- // General Usage:
- //
- // #include this file.
- // link with jpeglib2.lib
- //
- // All functions here are static. There is no need to have a JpegFile object.
- // There is actually nothing in a JpegFile object anyway.
- //
- // So, you can do this :
- //
- // BOOL ok = JpegFile::vertFlipBuf(buf, widthbytes, height);
- //
- // instead of this :
- //
- // JpegFile jpgOb;
- // BOOL ok = jpgOb.vertFlipBuf(buf, widthbytes, height);
- //
- /////
- //
- // Linking usage :
- // It is sometimes necessary to set /NODEFAULTLIB:LIBC (or LIBCD) to use this
- // class.
- //
- /////
- //
- // Error reporting:
- // The class generates message boxes in response to JPEG errors.
- //
- // The JpegFile.cpp fn my_error_exit defines the behavior for
- // fatal errors : show msg box, return to caller.
- //
- // Warnings are handled by jpeglib.lib - which generates msg boxes too.
- //
- ////////////////////////////////////////////////////////////////
- /*
- ////////////////////////////////////////////////////////////////
- // Reading Usage :
- UINT height;
- UINT width;
- BYTE *dataBuf;
- //read the file
- dataBuf=JpegFile::JpegFileToRGB(fileName,
- &width,
- &height);
- if (dataBuf==NULL) {
- return;
- }
- // RGB -> BGR
- JpegFile::BGRFromRGB(dataBuf, m_width, m_height);
- BYTE *buf;
- // create a DWORD aligned buffer from the JpegFile object
- buf = JpegFile::MakeDwordAlignedBuf(dataBuf,
- width,
- height,
- &m_widthDW);
- // flip that buffer
- JpegFile::VertFlipBuf(m_buf, m_widthDW, m_height);
- // you now have a buffer ready to be used as a DIB
- // be sure to delete [] dataBuf; // !!!!!!!!!!
- // delete [] buf;
- // Writing Usage
- // this assumes your data is stored as a 24-bit RGB DIB.
- // if you have a 1,4,8,15/16 or 32 bit DIB, you'll have to
- // do some work to get it into a 24-bit RGB state.
- BYTE *tmp=NULL;
- // assume buf is a DWORD-aligned BGR buffer, vertically flipped
- // as if read from a BMP file.
- // un-DWORD-align
- tmp=JpegFile::RGBFromDWORDAligned(buf,
- widthPix,
- widthBytes,
- height);
- // vertical flip
- JpegFile::VertFlipBuf(tmp, widthPix * 3, height);
- // reverse BGR
- JpegFile::BGRFromRGB(tmp, widthPix, height);
- if (tmp==NULL) {
- AfxMessageBox("~DWORD Memory Error");
- return;
- }
- // write it
- BOOL ok=JpegFile::RGBToJpegFile(fileName,
- tmp,
- width,
- height,
- TRUE,
- 75);
- if (!ok) {
- AfxMessageBox("Write Error");
- }
- delete [] tmp;
- ////////////////////////////////////////////////////////////////
- */
- //
- // for DWORD aligning a buffer
- //
- #define WIDTHBYTES(bits) (((bits) + 31) / 32 * 4)
- class JpegFile
- {
- public:
- ////////////////////////////////////////////////////////////////
- // read a JPEG file to an RGB buffer - 3 bytes per pixel
- // returns a ptr to a buffer .
- // caller is responsible for cleanup!!!
- // BYTE *buf = JpegFile::JpegFileToRGB(....);
- // delete [] buf;
- static BYTE * JpegFileToRGB(CString fileName, // path to image
- UINT *width, // image width in pixels
- UINT *height); // image height
- ////////////////////////////////////////////////////////////////
- // write a JPEG file from a 3-component, 1-byte per component buffer
- static BOOL RGBToJpegFile(CString fileName, // path
- BYTE *dataBuf, // RGB buffer
- UINT width, // pixels
- UINT height, // rows
- BOOL color, // TRUE = RGB
- // FALSE = Grayscale
- int quality); // 0 - 100
- ////////////////////////////////////////////////////////////////
- // fetch width / height of an image
- static BOOL GetJPGDimensions(CString fileName, // path
- UINT *width, // pixels
- UINT *height);
- ////////////////////////////////////////////////////////////////
- // utility functions
- // to do things like DWORD-align, flip, convert to grayscale, etc.
- //
- ////////////////////////////////////////////////////////////////
- // allocates a DWORD-aligned buffer, copies data buffer
- // caller is responsible for delete []'ing the buffer
- static BYTE * MakeDwordAlignedBuf(BYTE *dataBuf, // input buf
- UINT widthPix, // input pixels
- UINT height, // lines
- UINT *uiOutWidthBytes); // new width bytes
- ////////////////////////////////////////////////////////////////
- // if you have a DWORD aligned buffer, this will copy the
- // RGBs out of it into a new buffer. new width is widthPix * 3 bytes
- // caller is responsible for delete []'ing the buffer
- static BYTE *RGBFromDWORDAligned(BYTE *inBuf, // input buf
- UINT widthPix, // input size
- UINT widthBytes, // input size
- UINT height);
- ////////////////////////////////////////////////////////////////
- // vertically flip a buffer - for BMPs
- // in-place
- // note, this routine works on a buffer of width widthBytes: not a
- // buffer of widthPixels.
- static BOOL VertFlipBuf(BYTE * inbuf, // input buf
- UINT widthBytes, // input width bytes
- UINT height); // height
- // NOTE :
- // the following routines do their magic on buffers with a whole number
- // of pixels per data row! these are assumed to be non DWORD-aligned buffers.
- ////////////////////////////////////////////////////////////////
- // convert RGB to grayscale using luminance calculation
- // in-place
- static BOOL MakeGrayScale(BYTE *buf, // input buf
- UINT widthPix, // width in pixels
- UINT height); // height
- ////////////////////////////////////////////////////////////////
- // swap Red and Blue bytes
- // in-place
- static BOOL BGRFromRGB(BYTE *buf, // input buf
- UINT widthPix, // width in pixels
- UINT height); // lines
- ////////////////////////////////////////////////////////////////
- // these do nothing
- JpegFile(); // creates an empty object
- ~JpegFile(); // destroys nothing
- };