class EggClockFace < Gtk::DrawingArea def initialize super self.redraw_on_allocate=true signal_connect “expose_event” do |widget,event| ctx= widget.window.create_cairo_context ctx.rectangle(event.area.x, event.area.y, event.area.width, event.area.height) ctx.clip draw(ctx) false end end def draw(ctx) rect = allocation() x = rect.x + rect.width / 2.0 y = rect.y + rect.height / 2.0

    radius = [rect.width / 2.0, rect.height / 2.0].min - 5

    # clock back
    ctx.arc(x, y, radius, 0, 2.0 * Math::PI)
    ctx.set_source_rgb(1, 1, 1)
    ctx.fill_preserve()
    ctx.set_source_rgb(0, 0, 0)
    ctx.stroke()

    for i in 0..11
        inset = 0.1 * radius

        ctx.move_to(x + (radius - inset) * Math.cos(i * Math::PI / 6.0),
                        y + (radius - inset) * Math.sin(i * Math::PI / 6.0))
        ctx.line_to(x + radius * Math.cos(i * Math::PI / 6.0),
                        y + radius * Math.sin(i * Math::PI / 6.0))
        ctx.stroke()
    end
    ctx.stroke()

end end

Gtk.init window = Gtk::Window.new clock = EggClockFace.new

window.add(clock) window.signal_connect “destroy” do Gtk.main_quit end window.show_all()

Gtk.main()

require ‘cairo’ require ‘gtk2′

class EggClockFace

by installing first rcairo-1.0.0 and then ruby-gnome2-0.14.1 from source on ubuntu breezy (and after installing a boatload of xyz-dev packages with apt). The code could be more rubyified, anyway, but my box is dead ATM.

No time to blog it, though

1 - there’s no compelling reason to use super() instead of the old method in a single inheritance situation (anyway I corrected)

2 - ok for the floating point division

3 - draw() is an explicit override

4 - self.context is just a matter of style, I wrote the conversion quickly and this should be also a mistake

def init(self): gtk.DrawingArea.init(self)

I would recommend to use the super operator:

def init(self): super(EggClockFace, self).init()

rect = self.get_allocation() x = rect.x + rect.width / 2 y = rect.y + rect.height / 2

It’s probably better to make sure (for now) that floating point numbers are used for the division:

rect = self.get_allocation() x = rect.x + rect.width / 2.0 y = rect.y + rect.height / 2.0

Or if you want to force an integer division:

rect = self.get_allocation() x = rect.x + rect.width // 2 y = rect.y + rect.height // 2

def expose(self, widget, event): self.context = widget.window.cairo_create()

  self.draw(self.context)

Well, self.draw is actually an inherited method from gtk.Widget. I would recommend to rename that method to draw_face or something similar.

Also, why do you store the context in a member?

Thanks for your work and letting others enjoy it.

Rafael