flightgear/src/Instrumentation/HUD/HUD_label.cxx

// HUD_label.cxx -- HUD Label
//
// Written by Michele America, started September 1997.
//
// Copyright (C) 1997  Michele F. America  [micheleamerica#geocities:com]
// Copyright (C) 2006  Melchior FRANZ  [mfranz#aon:at]
//
// This program 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.
//
// This program 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
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include <simgear/props/condition.hxx>
#include "HUD.hxx"


HUD::Label::Label(HUD *hud, const SGPropertyNode *n, float x, float y) :
    Item(hud, n, x, y),
    _input(n->getNode("input", false)),
    _box(n->getBoolValue("box", false)),
    _pointer_width(n->getFloatValue("pointer-width", 7.0)),
    _pointer_length(n->getFloatValue("pointer-length", 5.0)),
    _blink_condition(0),
    _blink_interval(n->getFloatValue("blinking/interval", -1.0f)),
    _blink_target(0.0),
    _blink_state(true)
{
    const SGPropertyNode *node = n->getNode("blinking/condition");
    if (node)
       _blink_condition = sgReadCondition(globals->get_props(), node);

    const char *halign = n->getStringValue("halign", "center");
    if (!strcmp(halign, "left"))
        _halign = LEFT;
    else if (!strcmp(halign, "right"))
        _halign = RIGHT;
    else
        _halign = HCENTER;

    _halign |= VCENTER;

    const char *pre = n->getStringValue("prefix", 0);
    const char *post = n->getStringValue("postfix", 0);
    const char *fmt = n->getStringValue("format", 0);

    if (pre)
        _format = pre;

    if (fmt)
        _format += fmt;
    else
        _format += "%s";

    if (post)
        _format += post;

    _mode = check_format(_format.c_str());
    if (_mode == INVALID) {
        SG_LOG(SG_INPUT, SG_ALERT, "HUD: invalid format '" << _format.c_str() << '\'');
        _format = "INVALID";
        _mode = NONE;
    }

    blink();
}


void HUD::Label::draw(void)
{
    if (!(_mode == NONE || _input.isValid() && blink()))
        return;

    if (_box) {
        float l, r, p;
        float pw = _pointer_width / 2.0;

        l = _center_x - pw;
        r = _center_x + pw;
        bool draw_parallel = fabsf(_pointer_width - _w) > 2.0; // draw lines left and right of arrow?

        if (option_bottom()) {
            if (draw_parallel) {
                draw_line(_x, _y, l, _y);
                draw_line(r, _y, _x + _w, _y);
            }
            p = _y - _pointer_length;
            draw_line(l, _y, _center_x, p);
            draw_line(_center_x, p, r, _y);
        } else
            draw_line(_x, _y, _x + _w, _y);

        if (option_top()) {
            if (draw_parallel) {
                draw_line(_x, _y + _h, l, _y + _h);
                draw_line(r, _y + _h, _x + _w, _y + _h);
            }
            p = _y + _h + _pointer_length;
            draw_line(l, _y + _h, _center_x, p);
            draw_line(_center_x, p, r, _y + _h);
        } else
            draw_line(_x + _w, _y + _h, _x, _y + _h);

        l = _center_y - pw;
        r = _center_y + pw;
        draw_parallel = fabsf(_pointer_width - _h) > 2.0;

        if (option_left()) {
            if (draw_parallel) {
                draw_line(_x, _y, _x, l);
                draw_line(_x, r, _x, _y + _h);
            }
            p = _x - _pointer_length;
            draw_line(_x, l, p, _center_y);
            draw_line(p, _center_y, _x, r);
        } else
            draw_line(_x, _y + _h, _x, _y);

        if (option_right()) {
            if (draw_parallel) {
                draw_line(_x + _w, _y, _x + _w, l);
                draw_line(_x + _w, r, _x + _w, _y + _h);
            }
            p = _x + _w + _pointer_length;
            draw_line(_x + _w, l, p, _center_y);
            draw_line(p, _center_y, _x + _w, r);
        } else
            draw_line(_x + _w, _y, _x + _w, _y + _h);
    }

    const int BUFSIZE = 256;
    char buf[BUFSIZE];
    if (_mode == NONE)
        snprintf(buf, BUFSIZE, _format.c_str());
    else if (_mode == STRING)
        snprintf(buf, BUFSIZE, _format.c_str(), _input.getStringValue());
    else if (_mode == INT)
        snprintf(buf, BUFSIZE, _format.c_str(), int(_input.getFloatValue()));
    else if (_mode == LONG)
        snprintf(buf, BUFSIZE, _format.c_str(), long(_input.getFloatValue()));
    else if (_mode == FLOAT)
        snprintf(buf, BUFSIZE, _format.c_str(), float(_input.getFloatValue()));
    else if (_mode == DOUBLE) // not really supported yet
        snprintf(buf, BUFSIZE, _format.c_str(), double(_input.getFloatValue()));

    if (_halign & HCENTER)
        draw_text(_center_x, _center_y, buf, _halign, get_digits());
    else if (_halign & LEFT)
        draw_text(_x, _center_y, buf, _halign, get_digits());
    else // if (_halign & RIGHT)
        draw_text(_x + _w, _center_y, buf, _halign, get_digits());
}


// make sure the format matches '[ -+#]?\d*(\.\d*)?(l?[df]|s)'
//
HUD::Label::Format HUD::Label::check_format(const char *f) const
{
    bool l = false;
    Format fmt = STRING;

    for (; *f; f++) {
        if (*f == '%') {
            if (f[1] == '%')
                f++;
            else
                break;
        }
    }
    if (*f++ != '%')
        return NONE;
    if (*f == ' ' || *f == '+' || *f == '-' || *f == '#')
        f++;
    while (*f && isdigit(*f))
        f++;
    if (*f == '.') {
        f++;
        while (*f && isdigit(*f))
            f++;
    }
    if (*f == 'l')
        l = true, f++;

    if (*f == 'd')
        fmt = l ? LONG : INT;
    else if (*f == 'f')
        fmt = l ? DOUBLE : FLOAT;
    else if (*f == 's') {
        if (l)
            return INVALID;
        fmt = STRING;
    } else
        return INVALID;

    for (++f; *f; f++) {
        if (*f == '%') {
            if (f[1] == '%')
                f++;
            else
                return INVALID;
        }
    }
    return fmt;
}


bool HUD::Label::blink()
{
    if (_blink_interval < 0.0f)
        return true;

    if (_blink_condition && !_blink_condition->test())
        return true;

    if (_hud->timer() < _blink_target)
        return _blink_state;

    _blink_target = _hud->timer() + _blink_interval;
    return _blink_state = !_blink_state;
}