litex/migen/graph/treeviz.py

import cairo
import math

def _cairo_draw_node(ctx, dx, radius, color, outer_color, s):
	ctx.save()

	ctx.translate(dx, 0)

	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_dimensions(self):
		if self.children:
			cws, chs, cdxs = zip(*[c.get_dimensions() for c in self.children])
			w = sum(cws)
			h = self.pitch + max(chs)
			dx = cws[0]/4 - cws[-1]/4
		else:
			w = h = self.pitch
			dx = 0
		return w, h, dx

	def render(self, ctx):
		if self.children:
			cws, chs, cdxs = zip(*[c.get_dimensions() for c in self.children])
			first_child_x = -sum(cws)/2

			ctx.save()
			ctx.translate(first_child_x, self.pitch)
			for c, w in zip(self.children, cws):
				ctx.translate(w/2, 0)
				c.render(ctx)
				ctx.translate(w/2, 0)
			ctx.restore()

			dx = cws[0]/4 - cws[-1]/4

			current_x = first_child_x
			for c, w, cdx in zip(self.children, cws, cdxs):
				current_y = self.pitch - c.radius
				current_x += w/2
				_cairo_draw_connection(ctx, dx, self.radius, self.outer_color, current_x+cdx, current_y, c.outer_color)
				current_x += w/2
		else:
			dx = 0
		_cairo_draw_node(ctx, dx, self.radius, self.color, self.outer_color, self.label)

	def to_svg(self, name):
		w, h, dx = self.get_dimensions()
		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()