From cc5ff7a772b29ce5571172f9b32c70e4cb845221 Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sebastien@milkymist.org>
Date: Wed, 7 Aug 2013 15:52:35 +0200
Subject: [PATCH] add tree visualizer

---
 migen/graph/treeviz.py | 88 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 migen/graph/treeviz.py

diff --git a/migen/graph/treeviz.py b/migen/graph/treeviz.py
new file mode 100644
index 00000000..4e4c7750
--- /dev/null
+++ b/migen/graph/treeviz.py
@@ -0,0 +1,88 @@
+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()
-- 
2.30.2