summaryrefslogtreecommitdiff
path: root/Master/texmf-dist/tex/generic/pgf/graphdrawing/lua/pgf/gd/circular/Tantau2012.lua
blob: 8e0d7d5bc66e4a91b4d56ad5525af3968615e2cd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
-- Copyright 2012 by Till Tantau
--
-- This file may be distributed an/or modified
--
-- 1. under the LaTeX Project Public License and/or
-- 2. under the GNU Public License
--
-- See the file doc/generic/pgf/licenses/LICENSE for more information

-- @release $Header$


-- Imports
local declare = require("pgf.gd.interface.InterfaceToAlgorithms").declare

local routing = require("pgf.gd.routing")

-- The algorithm class
local Tantau2012 = {}

---
declare {
  key       = "simple necklace layout",
  algorithm = Tantau2012,
  
  postconditions = {
    upward_oriented = true
  },

  documentation_in = "pgf.gd.circular.doc"
}



-- Imports

local Coordinate = require "pgf.gd.model.Coordinate"
local Hints      = require "pgf.gd.routing.Hints"

local lib        = require "pgf.gd.lib"




-- The implementation

function Tantau2012:run()
  local g = self.ugraph
  local vertices = g.vertices
  local n = #vertices
  
  local sib_dists = self:computeNodeDistances ()
  local radii = self:computeNodeRadii()
  local diam, adjusted_radii = self:adjustNodeRadii(sib_dists, radii)

  -- Compute total necessary length. For this, iterate over all 
  -- consecutive pairs and keep track of the necessary space for 
  -- this node. We imagine the nodes to be aligned from left to 
  -- right in a line. 
  local carry = 0
  local positions = {}
  local function wrap(i) return (i-1)%n + 1 end
  local ideal_pos = 0
  for i = 1,n do
    positions[i] = ideal_pos + carry
    ideal_pos = ideal_pos + sib_dists[i]
    local node_sep =
      lib.lookup_option('node post sep', vertices[i], g) +
      lib.lookup_option('node pre sep', vertices[wrap(i+1)], g)
    local arc = node_sep + adjusted_radii[i] + adjusted_radii[wrap(i+1)] 
    local needed = carry + arc
    local dist = math.sin( arc/diam ) * diam
    needed = needed + math.max ((radii[i] + radii[wrap(i+1)]+node_sep)-dist, 0)
    carry = math.max(needed-sib_dists[i],0)    
  end
  local length = ideal_pos + carry

  local radius = length / (2 * math.pi)
  for i,vertex in ipairs(vertices) do
    vertex.pos.x = radius * math.cos(2 * math.pi * (positions[i] / length + 1/4))
    vertex.pos.y = -radius * math.sin(2 * math.pi * (positions[i] / length + 1/4))
  end

  -- Add routing infos
  local necklace = lib.icopy({g.vertices[1]}, lib.icopy(g.vertices))
  Hints.addNecklaceCircleHint(g, necklace, nil, true)
end


function Tantau2012:computeNodeDistances()
  local sib_dists = {}
  local sum_length = 0
  local vertices = self.digraph.vertices
  for i=1,#vertices do
    sib_dists[i] = lib.lookup_option('node distance', vertices[i], self.digraph)
    sum_length = sum_length + sib_dists[i]
  end

  local missing_length = self.digraph.options['radius'] * 2 * math.pi - sum_length
  if missing_length > 0 then
     -- Ok, the sib_dists to not add up to the desired minimum value. 
     -- What should we do? Hmm... We increase all by the missing amount:
     for i=1,#vertices do
	sib_dists[i] = sib_dists[i] + missing_length/#vertices
     end
  end

  sib_dists.total = math.max(self.digraph.options['radius'] * 2 * math.pi, sum_length)
  
  return sib_dists
end


function Tantau2012:computeNodeRadii()
  local radii = {}
  for i,v in ipairs(self.digraph.vertices) do
    local min_x, min_y, max_x, max_y = v:boundingBox()
    local w, h = max_x-min_x, max_y-min_y
    if v.shape == "circle" or v.shape == "ellipse" then
      radii[i] = math.max(w,h)/2
    else
      radii[i] = math.sqrt(w*w + h*h)/2
    end
  end
  return radii
end


function Tantau2012:adjustNodeRadii(sib_dists,radii)
  local total = 0
  local max_rad = 0
  for i=1,#radii do
    total = total + 2*radii[i] 
            + lib.lookup_option('node post sep', self.digraph.vertices[i], self.digraph)
            + lib.lookup_option('node pre sep', self.digraph.vertices[i], self.digraph)
    max_rad = math.max(max_rad, radii[i])  
  end
  total = math.max(total, sib_dists.total, max_rad*math.pi)
  local diam = total/(math.pi)
  
  -- Now, adjust the radii:
  local adjusted_radii = {}
  for i=1,#radii do
    adjusted_radii[i] = (math.pi - 2*math.acos(radii[i]/diam))*diam/2
  end
  
  return diam, adjusted_radii
end


-- done

return Tantau2012