test/test_draw.rb

@@ -0,0 +1,61 @@
+require 'igraph'
+require 'cairo'
+
+g = IGraph.barabasi_game(100,3,false,false)
+
+vertices = g.to_a
+layout   = g.send(ARGV.shift.to_sym,*ARGV.map{|a| eval(a)}).to_a
+
+format = Cairo::FORMAT_ARGB32
+width = 1000
+height = 1000
+
+surface = Cairo::ImageSurface.new(format, width, height)
+cr = Cairo::Context.new(surface)
+
+# fill background with white
+cr.set_source_rgba(1.0, 1.0, 1.0, 0.8)
+cr.paint
+
+max_x = layout.map{|a| a[0]}.max
+min_x = layout.map{|a| a[0]}.min
+max_y = layout.map{|a| a[1]}.max
+min_y = layout.map{|a| a[1]}.min
+
+x_var = max_x - min_x
+y_var = max_y - min_y
+
+max_var = [x_var,y_var].max
+
+layout.each_with_index do |a,i|
+  x,y = *a
+
+  x = (x - min_x)/max_var
+  y = (y - min_y)/max_var
+  x *= (width)
+  y *= (height)
+
+  layout[i] = [x,y]
+
+  puts "#{x} #{y}"
+
+end
+
+layout.each_with_index do |a,i|
+
+  v = vertices[i]
+  x,y = *a
+
+  cr.set_source_rgba(rand,rand,rand,0.5)
+  cr.circle(x,y,1).fill
+
+  g.adjacent_vertices(v,IGraph::OUT).each do |w|
+    cr.move_to(x,y)
+    wx,wy = *layout[vertices.index(w)]
+    cr.line_to(wx,wy)
+    cr.stroke
+  end
+
+end
+
+cr.target.write_to_png("test.png")