text: # Based on original code, Copyright 2004 Toby Dickenson,
  # with changes 2014 (c) Bjorn Pettersen
  #
  # Permission is hereby granted, free of charge, to any person obtaining
  # a copy of this software and associated documentation files (the
  # "Software"), to deal in the Software without restriction, including
  # without limitation the rights to use, copy, modify, merge, publish,
  # distribute, sublicense, and/or sell copies of the Software, and to
  # permit persons to whom the Software is furnished to do so, subject
  # to the following conditions:
  #
  # The above copyright notice and this permission notice shall be included
  # in all copies or substantial portions of the Software.
  #
  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  # EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  # IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
  # CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  # TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  # SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  from .render_context import RenderBuffer
  from . import colors
  
  
  class PyDepGraphDot(object):
      def __init__(self, **kw):
          self.kw = kw
  
      def render(self, depgraph, ctx):
          with ctx.graph():
              visited = set()
              drawn = set()
  
              for aname, bname in depgraph.cyclerelations:
                  try:
                      a = depgraph.sources[aname]
                      b = depgraph.sources[bname]
                  except KeyError:
                      continue
                  drawn.add((bname, aname))
                  ctx.write_rule(
                      aname, bname,
                      weight=depgraph.proximity_metric(a, b),
                      minlen=depgraph.dissimilarity_metric(a, b),
                  )
  
              for a, b in sorted(depgraph):
                  # b imports a
                  aname = a.name
                  bname = b.name
                  if (bname, aname) in drawn:
                      continue
                  drawn.add((bname, aname))
  
                  ctx.write_rule(
                      aname, bname,
                      weight=depgraph.proximity_metric(a, b),
                      minlen=depgraph.dissimilarity_metric(a, b))
  
                  visited.add(a)
                  visited.add(b)
  
              space = colors.ColorSpace(visited)
              for src in visited:
                  bg, fg = depgraph.get_colors(src, space)
                  kwargs = {}
  
                  if src.name in depgraph.cyclenodes:
                      kwargs['shape'] = 'octacon'
  
                  ctx.write_node(
                      src.name, label=src.label,
                      fillcolor=colors.rgb2css(bg),
                      fontcolor=colors.rgb2css(fg),
                      **kwargs
                  )
  
          return ctx.text()
  
  
  class CycleGraphDot(object):
      def __init__(self, **kw):
          self.kw = kw
  
      def render(self, depgraph, ctx):
          with ctx.graph(concentrate=False):
              visited = set()
              drawn = set()
  
              for aname, bname in depgraph.cyclerelations:
                  try:
                      a = depgraph.sources[aname]
                      b = depgraph.sources[bname]
                  except KeyError:
                      continue
                  drawn.add((bname, aname))
                  ctx.write_rule(
                      bname, aname,
                      weight=depgraph.proximity_metric(a, b),
                      minlen=depgraph.dissimilarity_metric(a, b),
                  )
                  visited.add(a)
                  visited.add(b)
  
              space = colors.ColorSpace(visited)
              for src in visited:
                  bg, fg = depgraph.get_colors(src, space)
                  kwargs = {}
  
                  if src.name in depgraph.cyclenodes:
                      kwargs['shape'] = 'octacon'
  
                  ctx.write_node(
                      src.name, label=src.label,
                      fillcolor=colors.rgb2css(bg),
                      fontcolor=colors.rgb2css(fg),
                      **kwargs
                  )
  
          return ctx.text()
  
  
  def dep2dot(target, depgraph, **kw):
      dotter = PyDepGraphDot(**kw)
      ctx = RenderBuffer(target, **kw)
      return dotter.render(depgraph, ctx)
  
  
  def cycles2dot(target, depgraph, **kw):
      dotter = CycleGraphDot(**kw)
      ctx = RenderBuffer(target, **kw)
      return dotter.render(depgraph, ctx)
  