Draw text on Gtk canvas

General Usage
5

Thanks again for your help.

In case it is useful for future reference, here is a simple example of what I am trying to accomplish

using Gtk, Graphics, Cairo, Colors
c = @GtkCanvas()
win = GtkWindow(c, "Canvas",500, 500)
@guarded draw(c) do widget
    ctx = getgc(c)
    # draw text 
    select_font_face(ctx, "Sans", Cairo.FONT_SLANT_NORMAL,
         Cairo.FONT_WEIGHT_NORMAL);
    set_font_size(ctx, 22.5);
    set_source_rgb(ctx, 0.8,0.8,0.8)
    extents = text_extents(cr, "X");
    x = 128.0-(extents[3]/2 + extents[1]);
    y = 128.0-(extents[4]/2 + extents[2]);
    move_to(ctx, x, y);
    show_text(ctx, "X");
    #draw red semi-transluecent rectangle
    circle(ctx, x + 15/2, y - 15/2, 15)
    set_source_rgba(ctx, 1, 0, 0, .5)
    # set_source(ctx, Cairo.alphacolor(colorant"red",.5))
    fill(ctx)
    restore(ctx)
end
show(c)