How to use the birdears.urwid.util.calc_width function in birdears

del new_row[-1]
            # we need another segment
            y_attr, y_cs, nlast_text = row[-2]
            nlast_cols = util.calc_width(nlast_text, 0,
                len(nlast_text))
            z_col += nlast_cols
            nlast_offs, y_col = util.calc_text_pos(nlast_text, 0,
                len(nlast_text), nlast_cols-1)
            y_text = nlast_text[nlast_offs:]
            if nlast_offs:
                new_row.append((y_attr, y_cs,
                    nlast_text[:nlast_offs]))
        else:
            z_text = last_text[last_offs:]
            y_attr, y_cs = z_attr, z_cs
            nlast_cols = util.calc_width(last_text, 0,
                last_offs)
            nlast_offs, y_col = util.calc_text_pos(last_text, 0,
                last_offs, nlast_cols-1)
            y_text = last_text[nlast_offs:last_offs]
            if nlast_offs:
                new_row.append((y_attr, y_cs,
                    last_text[:nlast_offs]))

        new_row.append((z_attr, z_cs, z_text))
        return new_row, z_col-y_col, (y_attr, y_cs, y_text)

# perfect space wrap
                b.append([(sc,p,pos),
                    # removed character hint
                    (0,pos)])
                p = pos+1
                continue
            if is_wide_char(text, pos):
                # perfect next wide
                b.append([(sc,p,pos)])
                p = pos
                continue
            prev = pos
            while prev > p:
                prev = move_prev_char(text, p, prev)
                if text[prev] == sp_o:
                    sc = calc_width(text,p,prev)
                    l = [(0,prev)]
                    if p!=prev:
                        l = [(sc,p,prev)] + l
                    b.append(l)
                    p = prev+1
                    break
                if is_wide_char(text,prev):
                    # wrap after wide char
                    next = move_next_char(text, prev, pos)
                    sc = calc_width(text,p,next)
                    b.append([(sc,p,next)])
                    p = next
                    break
            else:
                # unwrap previous line space if possible to
                # fit more text (we're breaking a word anyway)

if y in old_line_numbers:
                    old_line = y
                else:
                    old_line = old_line_numbers[0]
                send( "<%d\n"%old_line )
                continue

            col = 0
            for (a, cs, run) in row:
                run = run.translate(_trans_table)
                if a is None:
                    fg,bg,mono = "black", "light gray", None
                else:
                    fg,bg,mono = self.palette[a]
                if y == cy and col <= cx:
                    run_width = util.calc_width(run, 0,
                        len(run))
                    if col+run_width > cx:
                        l.append(code_span(run, fg, bg,
                            cx-col))
                    else:
                        l.append(code_span(run, fg, bg))
                    col += run_width
                else:
                    l.append(code_span(run, fg, bg))

            send("".join(l)+"\n")
        self.last_screen = new_screen
        self.last_screen_width = cols

        if self.update_method == "polling":
            sys.stdout.write("".join(sendq))

pos -- integer position into text
    clamp -- ignored right now
    """
    closest = None
    y = 0
    for line_layout in layout:
        x = 0
        for seg in line_layout:
            s = LayoutSegment(seg)
            if s.offs is None:
                x += s.sc
                continue
            if s.offs == pos:
                return x,y
            if s.end is not None and s.offs<=pos and s.end>pos:
                x += calc_width( text, s.offs, pos )
                return x,y
            distance = abs(s.offs - pos)
            if s.end is not None and s.end

continue
            prev = pos
            while prev > p:
                prev = move_prev_char(text, p, prev)
                if text[prev] == sp_o:
                    sc = calc_width(text,p,prev)
                    l = [(0,prev)]
                    if p!=prev:
                        l = [(sc,p,prev)] + l
                    b.append(l)
                    p = prev+1
                    break
                if is_wide_char(text,prev):
                    # wrap after wide char
                    next = move_next_char(text, prev, pos)
                    sc = calc_width(text,p,next)
                    b.append([(sc,p,next)])
                    p = next
                    break
            else:
                # unwrap previous line space if possible to
                # fit more text (we're breaking a word anyway)
                if b and (len(b[-1]) == 2 or ( len(b[-1])==1
                        and len(b[-1][0])==2 )):
                    # look for removed space above
                    if len(b[-1]) == 1:
                        [(h_sc, h_off)] = b[-1]
                        p_sc = 0
                        p_off = p_end = h_off
                    else:
                        [(p_sc, p_off, p_end),
                               (h_sc, h_off)] = b[-1]

def _last_row(self, row):
        """On the last row we need to slide the bottom right character
        into place. Calculate the new line, attr and an insert sequence
        to do that.

        eg. last row:
        XXXXXXXXXXXXXXXXXXXXYZ

        Y will be drawn after Z, shifting Z into position.
        """

        new_row = row[:-1]
        z_attr, z_cs, last_text = row[-1]
        last_cols = util.calc_width(last_text, 0, len(last_text))
        last_offs, z_col = util.calc_text_pos(last_text, 0,
            len(last_text), last_cols-1)
        if last_offs == 0:
            z_text = last_text
            del new_row[-1]
            # we need another segment
            y_attr, y_cs, nlast_text = row[-2]
            nlast_cols = util.calc_width(nlast_text, 0,
                len(nlast_text))
            z_col += nlast_cols
            nlast_offs, y_col = util.calc_text_pos(nlast_text, 0,
                len(nlast_text), nlast_cols-1)
            y_text = nlast_text[nlast_offs:]
            if nlast_offs:
                new_row.append((y_attr, y_cs,
                    nlast_text[:nlast_offs]))

for row in r.content():
            y += 1
            col = 0

            for a, cs, run in row:
                if not str is bytes:
                    run = run.decode()
                run = run.translate(_trans_table)
                if isinstance(a, AttrSpec):
                    aspec = a
                else:
                    aspec = self._palette[a][
                        {1: 1, 16: 0, 88:2, 256:3}[self.colors]]

                if y == cy and col <= cx:
                    run_width = util.calc_width(run, 0,
                        len(run))
                    if col+run_width > cx:
                        l.append(html_span(run,
                            aspec, cx-col))
                    else:
                        l.append(html_span(run, aspec))
                    col += run_width
                else:
                    l.append(html_span(run, aspec))

            l.append("\n")

        # add the fragment to the list
        self.fragments.append( "<pre>%s</pre>" % "".join(l) )

XXXXXXXXXXXXXXXXXXXXYZ

        Y will be drawn after Z, shifting Z into position.
        """

        new_row = row[:-1]
        z_attr, z_cs, last_text = row[-1]
        last_cols = util.calc_width(last_text, 0, len(last_text))
        last_offs, z_col = util.calc_text_pos(last_text, 0,
            len(last_text), last_cols-1)
        if last_offs == 0:
            z_text = last_text
            del new_row[-1]
            # we need another segment
            y_attr, y_cs, nlast_text = row[-2]
            nlast_cols = util.calc_width(nlast_text, 0,
                len(nlast_text))
            z_col += nlast_cols
            nlast_offs, y_col = util.calc_text_pos(nlast_text, 0,
                len(nlast_text), nlast_cols-1)
            y_text = nlast_text[nlast_offs:]
            if nlast_offs:
                new_row.append((y_attr, y_cs,
                    nlast_text[:nlast_offs]))
        else:
            z_text = last_text[last_offs:]
            y_attr, y_cs = z_attr, z_cs
            nlast_cols = util.calc_width(last_text, 0,
                last_offs)
            nlast_offs, y_col = util.calc_text_pos(last_text, 0,
                last_offs, nlast_cols-1)
            y_text = last_text[nlast_offs:last_offs]