L_FileConvert

Summary

Converts an image file from one format to another, creating a new file in the new format.

Syntax

#include "l_bitmap.h"

L_LTFIL_API L_INT L_FileConvert(pszFileSrc, pszFileDst, nType, nWidth, nHeight, nBitsPerPixel, nQFactor, pLoadOptions, pSaveOptions, pFileInfo)

Parameters

L_TCHAR* pszFileSrc

Character string containing the input file name.

L_TCHAR* pszFileDst

Character string containing the output file name.

L_INT nType

Output file format. For valid values, refer to Formats of Output Files.

L_INT nWidth

The new width of the output file. If this value is not 0, then the output file will be resized to the nWidth value. Use a value of 0 if you do not wish to resize the output file.

L_INT nHeight

The new height of the output file. If this value is not 0, then the output file will be resized to the nHeight value. Use a value of 0 if you do not wish to resize the output file.

L_INT nBitsPerPixel

The output file pixel depth. Note that not all bits per pixel are available to all file formats. For valid values, refer to Formats of Output Files.

L_INT nQFactor

This parameter is used when saving an image to file format that supports quality factor (QFactor). QFactor is a number that determines the degree of loss in the compression process.

For possible values, refer to Compression Quality Factors.

pLOADFILEOPTION pLoadOptions

Pointer to optional extended load options. Pass NULL to use the default load options.

pSAVEFILEOPTION pSaveOptions

Pointer to optional extended save options. Pass NULL to use the default save options.

pFILEINFO pFileInfo

Pointer to a FILEINFO structure. This structure may contain file information used in loading an image, or it may be updated with information about the file being loaded.

Never pass an uninitialized FILEINFO structure. If nothing is known about the file, pass NULL for this parameter; or declare a variable of type FILEINFO and set the FILEINFO.Flags to 0, then pass the address of the FILEINFO structure in this parameter. In this last case, if the address of a FILEINFO structure is passed the FILEINFO structure will be updated with the results of L_FileInfo.

If only the file type is known, set pFileInfo.Format to the file type and set pFileInfo.Flags to FILEINFO_FORMATVALID. This can also be done if L_FileInfo has been called previously, but values that affect the size of the image loaded have been changed (for example, by calling L_SetPCDResolution or L_SetWMFResolution). In this case the FILEINFO structure pointed to by pFileInfo will be updated with the results of L_FileInfo.

If L_FileInfo has been called prior to calling this function, and no changes have been made to the contents of the structure filled by L_FileInfo, then the address of the filled FILEINFO structure can be passed for this parameter. In this case, the FILEINFO.Flags member should be set to FILEINFO_INFOVALID. The L_FileInfo function will set the FILEINFO.Flags to FILEINFO_INFOVALID. In this case the load will be faster since this function does not have to query the file filters for the file type.

Note: Local variables are not initialized (since they are placed on the stack). So if you have a FILEINFO structure as a local variable, the value of its Flags parameter is undefined, possibly having FILEINFO_INFOVALID or FILEINFO_FORMATVALID set. That is why it is important to initialize FILEINFO.Flags before passing the address of the FILEINFO structure to the function.

Returns

Value	Meaning
SUCCESS	The function was successful.
< 1	An error occurred. Refer to Return Codes.

Comments

If you convert to a lower bits-per-pixel format, this function optimizes the colors automatically. For example, when converting a 24-bit file (16 million colors) to an 8-bit file (256 colors) this function selects the best 256 colors to represent the 24-bit image.

L_FileConvert is a high-level function that performs conversions from all possible formats to all possible formats.

To update a status bar or detect a user interrupt during execution of this function, refer to L_SetStatusCallback.

NOTE: You should never pass an uninitialized FILEINFO structure to this function.

Required DLLs and Libraries

LTFIL
For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

Platforms

Win32, x64, Linux.

Example

For complete sample code, refer to the FRAME.C module of the DEMO example.
This example converts a LEAD CMP file to a Windows BMP file

L_INT FileConvertExample(L_VOID) 
{ 
   L_INT nRet; 
   nRet = L_FileConvert(MAKE_IMAGE_PATH(TEXT("ImageProcessingDemo\\Image3.cmp")), /* Input file  */ 
                        MAKE_IMAGE_PATH(TEXT("TEST.BMP")),   /* Output file */ 
                        FILE_BMP,  /* Windows BMP file for output       */ 
                        0,         /* Keep the same width               */ 
                        0,         /* Keep the same height              */ 
                        8,         /* 8 bits per pixel                  */ 
                        0,         /* No quality factor is used for BMP */ 
                        NULL, 
                        NULL, NULL); 
   if(nRet != SUCCESS) 
      return nRet; 
   return SUCCESS; 
}