Dialogic 6.2 manual Accessing a TIFF-F File from an Application, Unsigned char buf1024 int n

Developing a Fax Application

BT_ZERO(args_strip); args_strip.fmt = DATA_G3; args_strip.resolution = RES_200H_100V; args_strip.width = WIDTH_A4; BfvFaxStripParams(lp,&args_strip); BT_ZERO(args_fax);

args_fax.fname = "g3_file"; args_fax.fmt = DATA_G3; BfvFaxSendFile(lp, &args_fax); BfvFaxEndOfDocument(lp, &args_fax);

Accessing a TIFF-F File from an Application

Although applications can directly read and write TIFF-F files with a set of Bfv library functions, some knowledge of TIFF-F file format is useful.

The BfvTiffOpen and BfvTiffClose functions open and close TIFF-F files, respectively.

The BfvTiffReadIFD and BfvTiffReadImage functions read an opened TIFF file. BfvTiffReadIFD calls a user-supplied function repeatedly with IFD entry information stored in an IFD (Image File Directory) for a particular page. The application can use fseek to move to locations in the TIFF file as directed by the tags (using the TIFF_FP(tp) macro to get the file pointer) and BfvTiffReadRes to help determine the resolution, as is often needed. The BfvTiffReadImage function puts data into a user-supplied buffer until the end of the page is reached.

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

main()

{

int my_ifd_func(); TFILE *tp;

unsigned char buf[1024]; int n;

struct args_tiff args_tiff; BT_ZERO(args_tiff); args_tiff.fname = "filename"; args_tiff.fmode = "r";

tp = BfvTiffOpen(&args_tiff); for (;;)

{

args_tiff.tp = tp;

args_tiff.func = my_ifd_func; args_tiff.arg = NULL;

if (BfvTiffReadIFD(&args_tiff) <= 0) break;

args_tiff.buf = buf;

args_tiff.size = sizeof(buf);

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