table management fixes

lib/qwaiter/distribution.rb

@@ -0,0 +1,47 @@
+module Qwaiter
+  module Distribution
+    module DistributionMethods
+      def epsilon
+        @@epsilon ||= (10 ** -(Float::DIG - 1)).to_f
+      end
+
+      ##
+      # Distribute a section of width w and height h in a length and a width scale
+      # that makes n tables fit.
+      #   distribute_lattice 10, 10, 3 #=> [5.0, 5.0]
+      #   distribute_lattice 10, 10, 4 #=> [5.0, 5.0]
+      ##
+      def distribute_lattice(w, h, n)
+        w, h = w.to_f, h.to_f
+        area = w*h
+        l = Math.sqrt(area.to_f/n)
+        nx = w/l
+        ny = h/l
+        while (w/l + epsilon).floor * (h/l + epsilon).floor < n
+          tx = w/l
+          ty = h/l
+          # The biggest remainder is closest to a fitting option
+          # Just add one if no remainder wins and it still is not enough
+          if tx.remainder(1) < epsilon && ty.remainder(1) < epsilon
+            # Both divide, but there is no solution yet. Just add one
+            l = [w/(tx + 1).round, h/(ty + 1).round].max
+            nx = tx.ceil
+            ny = ny.ceil
+          elsif tx.remainder(1) > ty.remainder(1)
+            nx = tx.ceil
+            ny = (n.to_f/nx).ceil
+            l = w/nx
+          else
+            ny = ty.ceil
+            nx = (n.to_f/ny).ceil
+            l = h/ny
+          end
+
+        end
+        [w/nx, h/ny]
+      end
+    end
+    include DistributionMethods
+    extend DistributionMethods
+  end
+end