lvjpeg.h

相机传输图像程序源代码 拜耳模式（RAW格式文件）与RGB图像数据互相转换函数库

/*                                                            *
 * LEUTRON VISION SUPPLEMENTAL LIBRARY FOR CONVERSION BETWEEN *
 * IN-MEMORY WINDOWS DEVICE INDEPENDENT BITMAP AND JPEG FILE  *
 *                                                            */

#ifndef LVJPEG_H
#define LVJPEG_H

#include <windows.h>

#if defined(__cplusplus)
  #define DLLENTRY extern "C" __declspec(dllexport)    
#else
  #define DLLENTRY __declspec(dllexport)
#endif

#define LV_DCT_DEFAULT 0
#define LV_DCT_FAST    1
#define LV_DCT_FLOAT   2

DLLENTRY BOOL WINAPI LvJpg_SaveBmpToJpgFile (BITMAPINFO* pBmpInfo,
                                             BYTE* pBmpData,
                                             const char* szFileName,
                                             int iQualityFactor, 
                                             int iDctMethod);

DLLENTRY BOOL WINAPI LvJpg_LoadBmpFromJpgFile (BITMAPINFO* pBmpInfo,
                                               BYTE* pBmpData,
                                               const char* szFileName,
                                               DWORD* pdwDataSize);

DLLENTRY void WINAPI LvJpg_GetLastErrorMessage (char* szMessage, int iMaxLength);

#endif


/*

BRIEF GUIDE
===============================================================================

DLLENTRY BOOL WINAPI LvJpg_SaveBmpToJpgFile (BITMAPINFO* pBmpInfo,
                                             BYTE* pBmpData,
                                             const char* szFileName,
                                             int iQualityFactor, 
                                             int iDctMethod);

Description:
-----------
  Compresses image from Windows Device Independent Bitmap and 
  saves it to the specified file.

  Supported formats: 
    8-bit (always saved as greyscaled)
    15-bit, 16-bit, 24-bit, 32-bit uncompressed

Parameters:
----------
  BITMAPINFO* pBmpInfo ...... Pointer to valid bitmap info structure.

  BYTE* pBmpData ............ Pointer to image data.

  const char* szFileName .... Name of the file (full path recommended).

  int iQualityFactor ........ Quality in range from 1 to 255, 
                              1 is the worst, 255 the best.

  int iDctMethod ............ LV_DCT_DEFAULT - slow, but accurate
                              LV_DCT_FAST    - fast, but less accurate
                              LV_DCT_FLOAT   - using floating point math, 
                                               accurate and maybe the fastest

Return value: 
------------
  TRUE if successful, FALSE if not - in such case call the 
  LvJpg_GetLastErrorMessage to get the error description.

-------------------------------------------------------------------------------

DLLENTRY BOOL WINAPI LvJpg_LoadBmpFromJpgFile (BITMAPINFO* pBmpInfo,
                                               BYTE* pBmpData,
                                               const char* szFileName,
                                               DWORD* pdwDataSize);

Description:
-----------
  Reads JPEG file and decompresses the image to the Windows Device Independent 
  Bitmap format.

  Supported formats: 
    Greyscale images are stored in 8-bit/pixel format,
    color images in 24-bit/pixel format.

Parameters:
----------
  BITMAPINFO* pBmpInfo ...... Pointer to bitmap info structure.
                              This stucture is filled after the JPEG header 
                              is read. Can be NULL.

  BYTE* pBmpData ............ Pointer to image data. Can be NULL - in such case
                              only the JPEG header is read in order to fill the
                              pBmpInfo and pdwDataSize. It is your responsibility
                              to allocate sufficiently large buffer and supply
                              it to this function.

  const char* szFileName .... Name of the file (full path recommended).

  DWORD* pdwDataSize ........ Returns size of the buffer that needs to be 
                              allocated for image data (pBmpData). Can be NULL.

  Typical usage: Call this function twice: First with pBmpData set NULL to obtain
  bitmap info and/or bitmap data size. Then allocate buffer for image data and call 
  the function the second time for image decompression.

  Example:

    DWORD dwSize;
    pBmpInfoHeader = (BITMAPINFOHEADER*) GlobalAlloc(GPTR, 
                            sizeof(BITMAPINFOHEADER) + 256*sizeof(RGBQUAD));
    if (LvJpg_LoadBmpFromJpgFile ((BITMAPINFO*) pBmpInfoHeader, 
                                   NULL, 
                                   "C:\\Test\\Test.jpg", 
                                   &dwSize))
     {
     pBmpData = (BYTE*) GlobalAlloc(GPTR, dwSize);
     LvJpg_LoadBmpFromJpgFile ((BITMAPINFO*) pBmpInfoHeader, 
                                pBmpData, 
                                "C:\\Test\\Test.jpg",
                                NULL);
     }


Return value: 
------------
  TRUE if successful, FALSE if not - in such case call the 
  LvJpg_GetLastErrorMessage to get the error description.

-------------------------------------------------------------------------------

DLLENTRY void WINAPI LvJpg_GetLastErrorMessage (char* szMessage, int iMaxLength);

Description:
-----------
  Returns last error message..

Parameters:
----------
  char* szMessage ........... Buffer for the returned message.
  
  int iMaxLength ............ Maximum message length 
                              (should be the buffer size - 1).


===============================================================================
   This DLL was programmed using the Independent JPEG Group's JPEG Library 
===============================================================================

*/