Dialogic 6.2 manual If n = BfvTiffReadImage&argstiff = 0 break Processimagebuf,n

Developing a Fax Application

if ((n = BfvTiffReadImage(&args_tiff)) <= 0) break;

process_image(buf,n);

}

args_tiff.tp = tp; BfvTiffClose(&args_tiff);}

my_ifd_func(tp, ifd_ptr, arg)

{

/* Does nothing,just returns */ return (0);

}

The BfvTiffWriteImage and BfvTiffWriteIFD functions are used to write a new TIFF file. BfvTiffWriteImage receives data from a user-supplied buffer until the end of the page is reached. The BfvTiffWriteIFD function is called repeatedly with IFD entry information. The application can use fseek to move to locations in the TIFF file to determine the proper offsets to use for a given tag (using the TIFF_FP(tp) macro to get the file pointer) and BfvTiffWriteRes to help write the resolution as is often needed.

The presence of a certain set of tags is required to produce a valid TIFF-F file; BfvTiffWriteIFD automatically takes care of the STRIPOFFSETS and STRIPBYTECOUNTS tags, but the application is responsible for all other tags.

A sample program to write a TIFF-F file follows:

main()

{

TFILE *tp;

unsigned char buf[1024]; int n;

struct ifd_field ifd_field; struct args_tiff args_tiff;

BT_ZERO(args_tiff);

args_tiff.fname = "filename"; args_tiff.fmode = "w";

tp = BfvTiffOpen(&args_tiff);

for (;;)

{

if ((n = get_image_data(buf)) <= 0) break;

args_tiff.tp = tp; args_tiff.buf = buf; args_tiff.size = n;

if (BfvTiffWriteImage(&args_tiff) != 0) break;

}

args_tiff.tp = tp; args_tiff.buf = NULL; args_tiff.size = 0

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