IG_info_get

This function obtains information about the file specified by the file handle, without loading the pixel data. This is an obsolete function, see remarks.

Declaration:

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AT_ERRCOUNT ACCUAPI IG_info_get_FD( AT_INT fd, LONG lOffset, UINT nPage, LPAT_MODE lpFileType, LPAT_MODE lpCompression, LPAT_DIB lpDIB );

Arguments:

Name	Type	Description
fd	AT_INT	Handle of the open file. This handle can be obtained from Microsoft Windows function such as CreateFile(), and cast to AT_INT for passing to the function parameter. FILE pointers returned by functions such as fopen(), and file handles returned by functions such as _sopen_s() are not supported.
lOffset	LONG	Offset into the file, in bytes, to where the image begins. This is the offset to the beginning of the header, not to the beginning of the bitmap. lOffset is usually 0.
nPage	UINT	Page number for which the info is obtained. Note that page numbers begin at 1, not 0. Set nPage to 1 if this is not a multi-page file.
lpFileType	LPAT_MODE	Pointer to an AT_MODE variable in which the file type will be returned. See enumIGFormats for possible values.
lpCompression	LPAT_MODE	Pointer to an AT_MODE variable in which compression type will be returned. See enumIGCompressions for possible values.
lpDIB	LPAT_DIB	Pointer to an AT_DIB structure to which other file information such as width, height, and Bits Per Pixel will be returned.

Return Value:

Returns 0 if successful. Otherwise, returns the number of ImageGear errors that occurred during this function call.

Supported Raster Image Formats:

If lpDIB is not NULL, then

Indexed RGB - 1, 4, 8 bpp;
Grayscale - 9...16 bpp;
RGB - 24 bpp;
CMYK - 32 bpp.

else - all pixel formats supported by ImageGear for C and C++.

Example:

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HANDLE fd; // File Descriptor AT_MODE nFileType; // Will receive an IG_FORMAT_ constant AT_MODE nCompression; // Will receive an IG_COMPRESSION_ constant AT_DIB atDIB; AT_ERRCOUNT nErrcount; // Returned count of errors fd = CreateFile(_T("picture.bmp"), GENERIC_READ, 0, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL); if(fd != INVALID_HANDLE_VALUE) { nErrcount = IG_info_get_FD((AT_INT)fd, 0, 1, &nFileType, &nCompression, &atDIB); CloseHandle(fd); // ... }

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HANDLE fd;                // File Descriptor
AT_MODE nFileType;        // Will receive an IG_FORMAT_ constant
AT_MODE nCompression;    // Will receive an IG_COMPRESSION_ constant
AT_DIB atDIB;
AT_ERRCOUNT nErrcount;        // Returned count of errors

fd = CreateFile(_T("picture.bmp"), GENERIC_READ,
        0, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
if(fd != INVALID_HANDLE_VALUE)
{
    nErrcount = IG_info_get_FD((AT_INT)fd, 0, 1, &nFileType, &nCompression, &atDIB);
    CloseHandle(fd);

    // ...
}

Remarks:

This function is only kept for backward compatibility reasons. Please use IG_info_get_FD_ex instead.

Any of the output parameters such as lpFileType, lpCompression or lpDIB can be NULL, if the corresponding info is not required.