% directions.w

% Copyright 2009-2010 Taco Hoekwater <taco@@luatex.org>

% This file is part of LuaTeX.

% LuaTeX is free software; you can redistribute it and/or modify it under
% the terms of the GNU General Public License as published by the Free
% Software Foundation; either version 2 of the License, or (at your
% option) any later version.

% LuaTeX is distributed in the hope that it will be useful, but WITHOUT
% ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
% FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
% License for more details.

% You should have received a copy of the GNU General Public License along
% with LuaTeX; if not, see <http://www.gnu.org/licenses/>.

@ @c
#include "ptexlib.h"

static const char _svn_version[] =
    "$Id: directions.w 3587 2010-04-03 14:32:25Z taco $"
    "$URL: http://foundry.supelec.fr/svn/luatex/tags/beta-0.70.1/source/texk/web2c/luatexdir/tex/directions.w $";

@ @c
void scan_direction(void)
{
    int save_cur_cmd = cur_cmd;
    int save_cur_chr = cur_chr;
    get_x_token();
    if (cur_cmd == assign_dir_cmd) {
        cur_val = eqtb[cur_chr].cint;
        goto EXIT;
    } else {
        back_input();
    }
    if (scan_keyword("TLT")) {
        cur_val = dir_TLT;
    } else if (scan_keyword("TRT")) {
        cur_val = dir_TRT;
    } else if (scan_keyword("LTL")) {
        cur_val = dir_LTL;
    } else if (scan_keyword("RTT")) {
        cur_val = dir_RTT;
    } else {
        tex_error("Bad direction", NULL);
        cur_val = 0;
    }
    get_x_token();
    if (cur_cmd != spacer_cmd)
        back_input();
  EXIT:
    cur_cmd = save_cur_cmd;
    cur_chr = save_cur_chr;
}

@ the next two are used by postlinebreak.c 

@c
halfword do_push_dir_node(halfword p, halfword a)
{
    halfword n;
    n = copy_node(a);
    vlink(n) = p;
    return n;
}

halfword do_pop_dir_node(halfword p)
{
    halfword n = vlink(p);
    flush_node(p);
    return n;
}

@ @c
halfword dir_ptr;

halfword text_dir_ptr;

@ There is no need to do anything here at the moment.
@c
void initialize_directions(void)
{
}

@ @c
halfword new_dir(int s)
{
    halfword p;                 /* the new node */
    p = new_node(whatsit_node, dir_node);
    dir_dir(p) = s;
    dir_dvi_ptr(p) = -1;
    dir_level(p) = cur_level;
    return p;
}

@ @c
const char *string_dir(int d)
{
    if (d == dir_TLT) {
        return "TLT";
    } else if (d == dir_TRT) {
        return "TRT";
    } else if (d == dir_LTL) {
        return "LTL";
    } else if (d == dir_RTT) {
        return "RTT";
    } else {
        return "???";
    }
}


@ @c
void print_dir(int d)
{
    tprint(string_dir(d));
}

@ @c
scaled pack_width(int curdir, int pdir, halfword p, boolean isglyph)
{
    scaled wd = 0;
    if (isglyph) {
        if (textdir_parallel(curdir, pdir) ==
            textglyphdir_orthogonal(pdir))
            wd = glyph_width(p);
        else
            wd = glyph_depth(p) + glyph_height(p);
    } else {                    /* hlist, vlist, image, form, rule */
        if (textdir_parallel(pdir, curdir))
            wd = width(p);
        else
            wd = depth(p) + height(p);
    }
    return wd;
}

@ @c
scaled_whd pack_width_height_depth(int curdir, int pdir, halfword p,
                                   boolean isglyph)
{
    scaled_whd whd = { 0, 0, 0 };
    whd.wd = pack_width(curdir, pdir, p, isglyph);
    if (isglyph) {
        if (is_rotated(curdir)) {
            if (textdir_parallel(curdir, pdir))
                whd.ht = whd.dp = (glyph_height(p) + glyph_depth(p)) / 2;
            else
                whd.ht = whd.dp = glyph_width(p) / 2;
        } else {
            if (is_rotated(pdir)) {
                if (textdir_parallel(curdir, pdir))
                    whd.ht = whd.dp = (glyph_height(p) + glyph_depth(p)) / 2;
                else
                    whd.ht = glyph_width(p);
            } else {
                if (glyphdir_eq(curdir, pdir)) {
                    whd.ht = glyph_height(p);
                    whd.dp = glyph_depth(p);
                } else if (glyphdir_opposite(curdir, pdir)) {
                    whd.ht = glyph_depth(p);
                    whd.dp = glyph_height(p);
                } else
                    whd.ht = glyph_width(p);
            }
        }
    } else {
        if (is_rotated(curdir)) {
            if (textdir_parallel(curdir, pdir))
                whd.ht = whd.dp = (height(p) + depth(p)) / 2;
            else
                whd.ht = whd.dp = width(p) / 2;
        } else {
            if (pardir_eq(curdir, pdir)) {
                whd.ht = height(p);
                whd.dp = depth(p);
            } else if (pardir_opposite(curdir, pdir)) {
                whd.ht = depth(p);
                whd.dp = height(p);
            } else
                whd.ht = width(p);
        }
    }
    return whd;
}

@ @c
void update_text_dir_ptr(int val)
{
    if (dir_level(text_dir_ptr) == cur_level) {
        /* update */
        dir_dir(text_dir_ptr) = val;
    } else {
        /* addition */
        halfword text_dir_tmp = new_dir(val);
        vlink(text_dir_tmp) = text_dir_ptr;
        text_dir_ptr = text_dir_tmp;
    }
}