code / hill-noise

   1 local Histogram = setmetatable({}, {__call=function(self,options)
   2     local h = setmetatable({},{__index=self})
   3     h:init(options)
   4     return h
   5 end})
   6 
   7 function Histogram:init(options)
   8     self.pos = options.pos
   9     self.size = options.size
  10     local total = 0
  11     for _,entry in ipairs(options.data) do
  12         local x, count = unpack(entry)
  13         total = total + count
  14     end
  15     local t = 0
  16     local iqrMin, iqrMax
  17     for _,entry in ipairs(options.data) do
  18         local x, count = unpack(entry)
  19         t = t + count
  20         if not iqrMin and t >= .25*total then iqrMin = x end
  21         if not iqrMax and t >= .75*total then iqrMax = x end
  22     end
  23     local h = 2*(iqrMax-iqrMin)*total^(1/3)
  24     local xmin, xmax = options.xmin or options.data[1][1], options.xmax or options.data[#options.data][1]
  25     local numBuckets = options.numBuckets or math.max(3, math.min(options.size.x/10, math.ceil((xmax - xmin) * total / h)))
  26     local buckets = {}
  27     for i=1,numBuckets do
  28         buckets[i] = 0
  29     end
  30     local ymax = 0
  31     for _,entry in ipairs(options.data) do
  32         local x, count = unpack(entry)
  33         local b = 1 + math.floor((x - xmin)/(xmax - xmin) * (numBuckets-1))
  34         buckets[b] = (buckets[b] or 0) + count
  35         ymax = math.max(buckets[b], ymax)
  36     end
  37     self.ymax = ymax
  38     self.xmax = xmax
  39     self.buckets = buckets
  40     function self:getX(x)
  41         return self.pos.x + self.size.x * (x-xmin)/(xmax-xmin)
  42     end
  43 end
  44 
  45 function Histogram:fromList(list, options)
  46     table.sort(list)
  47     local data = {}
  48     for _,x in ipairs(list) do
  49         if not data[#data] or data[#data][1] ~= x then
  50             table.insert(data, {x,1})
  51         else
  52             data[#data][2] = data[#data][2] + 1
  53         end
  54     end
  55     options.data = data
  56     return Histogram(options)
  57 end
  58 
  59 function Histogram:draw()
  60     local height = self.size.y / (#self.buckets-1)
  61     for i,count in ipairs(self.buckets) do
  62         if count > 0 then
  63             local width = count/self.ymax * self.size.x
  64             love.graphics.rectangle('fill', self.pos.x,
  65                 self.pos.y+(#self.buckets-i-1)*height, width, height)
  66         end
  67     end
  68 end
  69 
  70 return Histogram