1 files changed, 49 insertions, 0 deletions
diff --git a/lib/axlsx/workbook/worksheet/dimension.rb b/lib/axlsx/workbook/worksheet/dimension.rb
new file mode 100644
index 00000000..838b4ffa
--- /dev/null
+++ b/lib/axlsx/workbook/worksheet/dimension.rb
@@ -0,0 +1,49 @@
+module Axlsx
+
+  # This class manages the dimensions for a worksheet.
+  # While this node is optional in the specification some readers like 
+  # LibraOffice require this node to render the sheet
+  class Dimension
+
+
+    def self.default_first
+      @@default_first ||= 'A1'
+    end
+
+    def self.default_last
+      @@default_last ||= 'AA200'
+    end
+
+
+    def initialize(worksheet)
+      raise ArgumentError, "you must provide a worksheet" unless worksheet.is_a?(Worksheet)
+      @worksheet = worksheet
+    end
+
+    attr_reader :worksheet
+
+    def sqref
+      "#{first_cell_reference}:#{last_cell_reference}"
+    end 
+
+    def to_xml_string(str = '')
+      return if worksheet.rows.empty?
+      str << "<dimension ref=\"%s\"></dimension>" % sqref
+    end
+
+    def first_cell_reference
+      dimension_reference(worksheet.rows.first.cells.first, Dimension.default_first)
+    end
+
+    def last_cell_reference
+      dimension_reference(worksheet.rows.last.cells.last, Dimension.default_last)
+    end
+
+    private
+
+    def dimension_reference(cell, default)
+      return default unless cell.respond_to?(:r)
+      cell.r
+    end
+  end
+end