--- /dev/null
+import cairo
+import math
+
+def _cairo_draw_node(ctx, radius, color, outer_color, s):
+ ctx.save()
+
+ ctx.set_line_width(0.0)
+ gradient_color = cairo.RadialGradient(0, 0, 0, 0, 0, radius)
+ gradient_color.add_color_stop_rgb(0, *color)
+ gradient_color.add_color_stop_rgb(1, *outer_color)
+ ctx.set_source(gradient_color)
+ ctx.arc(0, 0, radius, 0, 2*math.pi)
+ ctx.fill()
+
+ ctx.set_source_rgb(0, 0, 0)
+ x_bearing, y_bearing, textw, texth, x_advance, y_advance = ctx.text_extents(s)
+ ctx.translate(-textw/2, texth/2)
+ ctx.show_text(s)
+
+ ctx.restore()
+
+def _cairo_draw_connection(ctx, x0, y0, color0, x1, y1, color1):
+ ctx.move_to(x0, y0)
+ ctx.curve_to(x0, y0+20, x1, y1-20, x1, y1)
+ ctx.set_line_width(1.2)
+ gradient_color = cairo.LinearGradient(x0, y0, x1, y1)
+ gradient_color.add_color_stop_rgb(0, *color0)
+ gradient_color.add_color_stop_rgb(1, *color1)
+ ctx.set_source(gradient_color)
+ ctx.stroke()
+
+class RenderNode:
+ def __init__(self, label, children=None, color=(0.8, 0.8, 0.8), radius=40):
+ self.label = label
+ if children is None:
+ children = []
+ self.children = children
+ self.color = color
+ self.outer_color = (color[0]*3/5, color[1]*3/5, color[2]*3/5)
+ self.radius = radius
+ self.pitch = self.radius*3
+
+ def get_extents(self):
+ if self.children:
+ cw, ch = zip(*[c.get_extents() for c in self.children])
+ w = max(cw)*len(self.children)
+ h = self.pitch + max(ch)
+ else:
+ w = h = self.pitch
+ return w, h
+
+ def render(self, ctx):
+ _cairo_draw_node(ctx, self.radius, self.color, self.outer_color, self.label)
+ if self.children:
+ cpitch = max([c.get_extents()[0] for c in self.children])
+ first_child_x = -(cpitch*(len(self.children) - 1))/2
+
+ ctx.save()
+ ctx.translate(first_child_x, self.pitch)
+ for c in self.children:
+ c.render(ctx)
+ ctx.translate(cpitch, 0)
+ ctx.restore()
+
+ current_x = first_child_x
+ for c in self.children:
+ current_y = self.pitch - c.radius
+ _cairo_draw_connection(ctx, 0, self.radius, self.outer_color, current_x, current_y, c.outer_color)
+ current_x += cpitch
+
+ def to_svg(self, name):
+ w, h = self.get_extents()
+ surface = cairo.SVGSurface(name, w, h)
+ ctx = cairo.Context(surface)
+ ctx.translate(w/2, self.pitch/2)
+ self.render(ctx)
+ surface.finish()
+
+def _test():
+ xns = [RenderNode("X"+str(n)) for n in range(5)]
+ yns = [RenderNode("Y"+str(n), [RenderNode("foo", color=(0.1*n, 0.5+0.2*n, 1.0-0.3*n))]) for n in range(3)]
+ n1 = RenderNode("n1", yns)
+ n2 = RenderNode("n2", xns, color=(0.8, 0.5, 0.9))
+ top = RenderNode("top", [n1, n2])
+ top.to_svg("test.svg")
+
+if __name__ == "__main__":
+ _test()