clock.cc

#include <ctime>
#include <cmath>
#include <cairomm/context.h>
#include "clock.h"

Clock::Clock()
: m_radius(0.42), m_line_width(0.05)
{
  Glib::signal_timeout().connect( sigc::mem_fun(*this, &Clock::on_timeout), 1000 );

  #ifndef GLIBMM_DEFAULT_SIGNAL_HANDLERS_ENABLED
  //Connect the signal handler if it isn't already a virtual method override:
  signal_expose_event().connect(sigc::mem_fun(*this, &Clock::on_expose_event), false);
  #endif //GLIBMM_DEFAULT_SIGNAL_HANDLERS_ENABLED
}

Clock::~Clock()
{
}

bool Clock::on_expose_event(GdkEventExpose* event)
{
  // This is where we draw on the window
  Glib::RefPtr<Gdk::Window> window = get_window();
  if(window)
  {
    Gtk::Allocation allocation = get_allocation();
    const int width = allocation.get_width();
    const int height = allocation.get_height();

    Cairo::RefPtr<Cairo::Context> cr = window->create_cairo_context();

    if(event)
    {
        // clip to the area indicated by the expose event so that we only
        // redraw the portion of the window that needs to be redrawn
        cr->rectangle(event->area.x, event->area.y,
                event->area.width, event->area.height);
        cr->clip();
    }

    // background gradient
    {
        Cairo::RefPtr<Cairo::LinearGradient> pat = Cairo::LinearGradient::create(0.0, 0.0, 0.0, height);
        pat->add_color_stop_rgb(1.0, 1.0, 1.0, 1.0);
        pat->add_color_stop_rgb(0.0, 0.0, 0.0, 0.0);
        cr->rectangle(0, 0, width, height);
        cr->set_source(pat);
        cr->fill();
    }

    // scale to unit square and translate (0, 0) to be (0.5, 0.5), i.e.
    // the center of the window
    cr->scale(width, height);
    cr->translate(0.5, 0.5);
    cr->set_line_width(m_line_width);

    cr->arc(0, 0, m_radius, 0, 2 * M_PI);
    cr->save();
    cr->set_source_rgba(1.0, 1.0, 1.0, 0.8);
    cr->fill_preserve();
    cr->restore();
    cr->stroke_preserve();
    cr->clip();

    //clock ticks
    for (int i = 0; i < 12; i++)
    {
        double inset = 0.05;

        cr->save();
        cr->set_line_cap(Cairo::LINE_CAP_ROUND);

        if(i % 3 != 0)
        {
            inset *= 0.8;
            cr->set_line_width(0.03);
        }

        cr->move_to(
                (m_radius - inset) * cos (i * M_PI / 6),
                (m_radius - inset) * sin (i * M_PI / 6));
        cr->line_to (
                m_radius * cos (i * M_PI / 6),
                m_radius * sin (i * M_PI / 6));
        cr->stroke();
        cr->restore(); /* stack-pen-size */
    }

    // store the current time
    time_t rawtime;
    time(&rawtime);
    struct tm * timeinfo = localtime (&rawtime);

    // compute the angles of the indicators of our clock
    double minutes = timeinfo->tm_min * M_PI / 30;
    double hours = timeinfo->tm_hour * M_PI / 6;
    double seconds= timeinfo->tm_sec * M_PI / 30;

    cr->save();
    cr->set_line_cap(Cairo::LINE_CAP_ROUND);

    // draw the seconds hand
    cr->save();
    cr->set_line_width(m_line_width / 3);
    cr->set_source_rgba(0.7, 0.7, 0.7, 0.8); // gray
    cr->move_to(0, 0);
    cr->line_to(sin(seconds) * (m_radius * 0.9), 
            -cos(seconds) * (m_radius * 0.9));
    cr->stroke();
    cr->restore();

    // draw the minutes hand
    cr->set_source_rgba(0.117, 0.337, 0.612, 0.9);   // blue
    cr->move_to(0, 0);
    cr->line_to(sin(minutes + seconds / 60) * (m_radius * 0.8),
            -cos(minutes + seconds / 60) * (m_radius * 0.8));
    cr->stroke();

    // draw the hours hand
    cr->set_source_rgba(0.337, 0.612, 0.117, 0.9);   // green
    cr->move_to(0, 0);
    cr->line_to(sin(hours + minutes / 12.0) * (m_radius * 0.5),
            -cos(hours + minutes / 12.0) * (m_radius * 0.5));
    cr->stroke();
    cr->restore();

    // draw a little dot in the middle
    cr->arc(0, 0, m_line_width / 3.0, 0, 2 * M_PI);
    cr->fill();
  }

  return true;
}


bool Clock::on_timeout()
{
    // force our program to redraw the entire clock.
    Glib::RefPtr<Gdk::Window> win = get_window();
    if (win)
    {
        Gdk::Rectangle r(0, 0, get_allocation().get_width(),
                get_allocation().get_height());
        win->invalidate_rect(r, false);
    }
    return true;
}