Accessing a tiff-f file from an application – Dialogic 6.2 User Manual

Page 87

Developing a Fax Application

November 2009

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);