Text Subwindow line number

[zifrony at TAURUS.BITNET]

In Sun-Spots Digest, v7n47, unido!infhil!sun1a!boeker at uunet.uu.net
(Michael Boeker) needed to know how to determine the line number of a
position.  As I have encountered a similar problem, needing to find the
line number clicked on by the user, I have the following method to solve
it:

 1. I have created a mapping of the text window, noting in which position
    each line starts by using textsw_index_for_file_line().

 2. I have determined the location of the cursor in the text (the place where
    the user clicked), by using window_get(src, TEXTSW_INSERTION_POINT, 0),
    where src is my Textsw subwindow.  Note that dbxtool does it in a smoother
    way, and keeps the Textsw subwindow readonly; alas, I do not have the
    source of dbxtool, and had to resort to these means to solve the problem.

 3. I looped through my mapping, finding the first line whose first character
    index is greater than my position, and voila, the line is found.

Please note that the file I am working with is not too big, thus the
search loop does not take too long.  For huge files, I suppose a better
way has to be sought to solve the problem.

 Doron Zifrony                  zifrony at taurus.bitnet || zifrony at Math.Tau.Ac.IL
 Msc. Student
 Tel Aviv University
 Israel