lib/in_columns/columnizer.rb in in_columns-0.1.0 vs lib/in_columns/columnizer.rb in in_columns-0.2.0

@@ -2,27 +2,59 @@
   class Columnizer
     def initialize(elements)
       @elements = elements
     end
 
-    def columns(number_of_columns)
-      columns = create_columns(number_of_columns)
-      distribute_elements(columns)
+    # Returns the necessary rows to distribute elements into the desired number
+    # of columns
+    #
+    # The result is a multidimensional array, so that:
+    #
+    #   Columnizer.new(['a', 'b', 'c']).distribute(2)
+    #   #=> [['a', 'c'], ['b', nil]]
+    def distribute(number_of_columns)
+      return [] if elements.empty?
+      distribute_elements(number_of_columns)
     end
 
     private
 
     attr_reader :elements
 
-    def create_columns(number_of_columns)
-      (1..number_of_columns).collect { [] }
+    def distribute_elements(number_of_columns)
+      number_of_rows = (number_of_elements.to_f / number_of_columns).ceil
+      counts = row_counts(number_of_columns)
+
+      columns = []
+      elements_to_distribute = elements.dup
+
+      while !elements_to_distribute.empty?
+        size_of_column = counts[columns.size]
+        elements_for_column = elements_to_distribute.shift(size_of_column)
+        columns << elements_for_column
+      end
+
+      # Convert the columns to rows
+      first_column = columns.first
+      rest_columns = columns[1..-1]
+      columns = first_column.zip(*rest_columns)
     end
 
-    def distribute_elements(columns)
-      elements.each_with_index { |element, index|
-        column_number = index % columns.size
-        columns[column_number] << element
+    def number_of_elements
+      elements.size
+    end
+
+    # Returns an array with an element for each column containing the number of
+    # rows for that column
+    def row_counts(number_of_columns)
+      per_column = (number_of_elements / number_of_columns).floor
+      counts = [per_column] * number_of_columns
+
+      left_overs = number_of_elements % number_of_columns
+      left_overs.times { |n|
+        counts[n] = counts[n] + 1
       }
-      columns
+
+      counts
     end
   end
 end