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CSS

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HTML 

              
                <svg id='board'>
  <g id='lines'></g>
  <g id='circles'></g>
</svg>
<div id='buttons'>
  <button id='regenerate'>Regenerate Graph</button>
  <button id='bfs'>Start BFS</button>
</div>
!

CSS 

              
                body {
  padding: 0;
  margin: 0;
  border: none;
  background-color: black;
}

circle {
  fill: white;
  cursor: pointer;
}

circle:hover {
  fill:pink;
}

#buttons {
  opacity: 0;
  position:absolute;
  left: 10px;
  bottom: 10px;
}
!

JS 

              
                # VIEW SETUP STUFF
OUTER_MARGIN = 10.0
SVG_ELEMENT = d3.select '#board'
SVG_CIRCLES = SVG_ELEMENT.select('#circles')
SVG_LINES   = SVG_ELEMENT.select('#lines')

windowWidth = window.innerWidth
windowHeight = window.innerHeight

svgWidth = windowWidth - 2 * OUTER_MARGIN
svgHeight = windowHeight - 2 * OUTER_MARGIN

px = (x) -> String(x) + 'px'

SVG_ELEMENT.attr  'width',       px svgWidth
           .attr  'height',      px svgHeight
           .style 'margin-left', px OUTER_MARGIN
           .style 'margin-top',  px OUTER_MARGIN
      
# GOODIES
class Queue
  constructor: () ->
    @arr = []
    @p1 = 0
    @p2 = 0
    return
  
  push: (a) -> 
    @p2 += 1
    @arr.push(a)
    return
    
  squish: () ->
    @arr.splice(0, @p1)
    @p2 = @p2 - @p1
    @p1 = 0
    return
  
  front: () -> @arr[@p1]
  
  pop: () ->
    if @isEmpty() 
      return
    x = @arr[@p1]
    @arr[@p1] = 
    @p1 += 1
    if @isEmpty()
      @arr = []
      @p1 = 0
      @p2 = 0
    else if (@p2 - @p1) < @p2 / 2
      @squish()
    x
  
  isEmpty: () -> @p1 == @p2
    
diag  = (w, h) -> Math.sqrt(w * w + h * h)
ranbt = (a, b) -> a + Math.random() * (b - a)
ranIntbt = (a, b) -> parseInt(ranbt a, b)

colorOpen = (color, factor) ->
  rrr = 255 * factor
  res = 'black'
  if color == 'red'
    res = "rgb(255, #{rrr}, #{rrr})"
  else if color == 'green'
    res = "rgb(#{rrr}, 255, #{rrr})"
  else if color == 'blue' || color == 'green'
    res = "rgb(#{rrr}, #{rrr}, 255)"
  res

class Point
  constructor: (@x, @y) ->
    return
  
  distanceTo: (a) -> Math.sqrt((@x - a.x) * (@x - a.x) + (@y - a.y) * (@y - a.y))

  randomPointInAnnulus: (r1, r2) ->
    r = ranbt(r1, r2)
    a = ranbt(0, 2 * Math.PI)
    new Point(@x + r * Math.cos(a), @y + r * Math.sin(a))

randomPoint = (x1, y1, x2, y2) -> new Point(ranbt(x1, x2), ranbt(y1, y2))

# LOGIC STUFF
class PoissonDisk
  constructor: (@boardWidth, 
                @boardHeight, 
                @minDistance, 
                @candidatesSize, 
                @newPointCallback, 
                @newLineCallback, 
                @doneCallback) ->
    @cellSize = @minDistance / Math.SQRT2
    @cellsWide = Math.ceil @boardWidth / @cellSize
    @cellsHigh = Math.ceil @boardHeight / @cellSize
    @allPoints = []
    @grid = []
    for i in [0..@cellsHigh - 1]
      tarr = []
      for j in [0..@cellsWide - 1]
        tarr.push -1
      @grid.push tarr
    return
    
  sample: () ->
    fp = new Point(ranbt(50, @boardWidth - 50), ranbt(50, @boardHeight - 50))
    
    @grid[parseInt(fp.y / @cellSize)][parseInt(fp.x / @cellSize)] = 0
    
    @allPoints.push fp
    @newPointCallback fp.x, fp.y, 0
    q = new Queue()
    q.push(0)
    
    _candidatesSize  = @candidatesSize
    _newPointCallback = @newPointCallback
    _newLineCallback = @newLineCallback
    _doneCallback = @doneCallback
    _grid = @grid
    _cellSize = @cellSize
    _cellsWide = @cellsWide
    _cellsHigh = @cellsHigh
    _allPoints = @allPoints
    _minDistance = @minDistance
    _boardWidth = @boardWidth
    _boardHeight = @boardHeight
    
    testPoint = (point) ->
      row = parseInt point.y / _cellSize
      col = parseInt point.x / _cellSize
      res =
        goodClose: []
        goodCloseId: []
        isBad: false
      if point.x < 50 or point.x > _boardWidth - 50 or 
         point.y < 50 or point.y > _boardHeight - 50
        res.isBad = true
        return res
      for i in [-5..5]
        for j in [-5..5]
          prow = row + i
          pcol = col + j
          if prow < 0 or pcol < 0 or prow >= _cellsHigh or pcol >= _cellsWide
            continue
          if _grid[prow][pcol] > -1
            ppid = _grid[prow][pcol]
            pp = _allPoints[ppid]
            if point.distanceTo(pp) < _minDistance
              res.isBad = true
              return res
            if point.distanceTo(pp) < 2 * _minDistance
              res.goodClose.push pp
              res.goodCloseId.push ppid
      return res
    
    doWork = () ->
      found = false
      ppid = q.front()
      pp = _allPoints[ppid]
      for i in [1.._candidatesSize]
        gp = pp.randomPointInAnnulus(_minDistance, 2 * _minDistance)
        ttt = testPoint(gp)
        if !ttt.isBad
          row = parseInt gp.y / _cellSize
          col = parseInt gp.x / _cellSize
          _grid[row][col] = _allPoints.length
          gpid = _allPoints.length
          q.push gpid
          _allPoints.push gp
          _newPointCallback gp.x, gp.y, gpid
          found = true
          for ppwid in ttt.goodCloseId
            ppw = _allPoints[ppwid]
            _newLineCallback ppw.x, ppw.y, gp.x, gp.y, ppwid, gpid
      if found == false
        q.pop()
      if !q.isEmpty()
        setTimeout doWork, 0
      else
        setTimeout _doneCallback, 0
    
    setTimeout doWork, 0
    return

# CALL STUFF

graph = []

myNewPointCallback = (x, y, _id) ->
  domref = SVG_CIRCLES.append 'circle'
  domref.attr   'cx', x
        .attr   'cy', y
        .attr   'r',  diag(svgWidth, svgHeight) / 180 * 5
        .style  'opacity', 0.0
        .transition()
        .duration 250
        .style  'opacity', 1.0
        .attr   'r',  diag(svgWidth, svgHeight) / 180
  node =
    ref   : domref
    id    : _id
    edges : []
  graph.push node
  alll = () ->
    setTimeout () ->
      doBFS(_id)
      return
    , 0
    return
  domref.on('click', alll)
  return
        
myNewLineCallback = (x1, y1, x2, y2, id1, id2) ->
  edge = SVG_LINES.append 'line'
  edge.attr   'x1', x1
      .attr   'y1', y1
      .attr   'x2', x1
      .attr   'y2', y1
      .attr   'stroke-width', 1
      .attr   'stroke', 'white'
      .transition()
      .duration 500
      .attr   'x2', x2
      .attr   'y2', y2
  n1ton2 =
    ref : edge
    end : id2
  n2ton1 =
    ref : edge
    end : id1
  graph[id1].edges.push n1ton2
  graph[id2].edges.push n2ton1
            
active = true
myDoneCallback = () ->
  active = true
  d3.select('#regenerate').attr('disabled', null)
  d3.select('#bfs').attr('disabled', null)

doWork = () -> 
  graph = []
  if !active
    return
  active = false
  d3.select('#regenerate').attr('disabled', 'disabled')
  d3.select('#bfs').attr('disabled', 'disabled')
  SVG_CIRCLES.selectAll('*').remove()
  SVG_LINES  .selectAll('*').remove()
  a = new PoissonDisk svgWidth,
                      svgHeight,
                      # minDistance, candidateSize
                      diag(svgWidth, svgHeight) / 30, 30,
                      myNewPointCallback, 
                      myNewLineCallback, 
                      myDoneCallback
  a.sample()

d3.select('#regenerate').on('click', doWork)
doWork()













cl = 0
cls = ['red', 'blue', 'green']

doBFS = (startNodeId) ->
  
  d3.select('#regenerate').attr('disabled', 'disabled')
  d3.select('#bfs').attr('disabled', 'disabled')
  
  cl = (cl + 1) % 3
  startNode   = graph[startNodeId]
  d3.selectAll('line').transition().style('stroke-width', 1)
                                   .style('stroke', 'lightgrey')
  
  visited = []
  deep    = []
  for x in graph
    visited.push false
    deep.push -1
  
  visited[startNodeId] = true
  deep[startNodeId] = 0
  
  q = new Queue()
  q.push(startNodeId)
  startNode.ref.style('fill', colorOpen(cls[cl], 0))
  startNode.ref.attr('r', diag(svgWidth, svgHeight) / 180 * 3)
  
  bfsssDone = () ->
    d3.select('#regenerate').attr('disabled', null)
    d3.select('#bfs').attr('disabled', null)
    return
  
  bfsss = () ->
    
    if q.isEmpty()
      setTimeout bfsssDone, 0
      return
    
    xId = q.pop()
    xNode = graph[xId]
    
    for edge in xNode.edges
      yId = edge.end
      yNode = graph[yId]
      if !visited[yId]
        q.push yId
        visited[yId] = true
        deep[yId] = deep[xId] + 1
        aug = Math.max(3 - deep[yId] / 5, 1)
        cll = Math.min((3 - aug) / 3, 1)
        fill = colorOpen(cls[cl], cll)
        console.log fill
        yNode.ref.transition().style('fill', fill)
                              .attr('r', diag(svgWidth, svgHeight) / 180 * aug)
        edge.ref.transition().style('stroke-width', aug * diag(svgWidth, svgHeight) / 500)
                             .style('stroke', fill)
    setTimeout bfsss, 0
  
  setTimeout bfsss, 0
  
  return

d3.select('#bfs').on('click', () ->
  startNodeId = ranIntbt(0, graph.length - 1)
  doBFS(startNodeId)
)
!
999px

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