Merge pull request #93 from redcap97/resolution_info

added support for ResolutionInfo

lib/psd/resources/base.rb

@@ -28,3 +28,4 @@ def name; self.class.name; end
 require 'psd/resources/layer_comps'
 require 'psd/resources/slices'
 require 'psd/resources/xmp_metadata'
+require 'psd/resources/resolution_info'

lib/psd/resources/resolution_info.rb

@@ -0,0 +1,48 @@
+require 'psd/resources/base'
+
+class PSD
+  class Resource
+    module Section
+      class ResolutionInfo < Base
+        RES_UNIT_NAMES = %w(pixel/inch pixel/cm).freeze
+        UNIT_NAMES = %w(in cm pt picas columns).freeze
+
+        resource_id 1005
+        name :resolution_info
+
+        attr_reader :h_res, :h_res_unit, :width_unit
+        attr_reader :v_res, :v_res_unit, :height_unit
+
+        def parse
+          # 32-bit fixed-point number (16.16)
+          @h_res = @file.read_uint.to_f / (1 << 16)
+          @h_res_unit = @file.read_ushort
+          @width_unit = @file.read_ushort
+
+          # 32-bit fixed-point number (16.16)
+          @v_res = @file.read_uint.to_f / (1 << 16)
+          @v_res_unit = @file.read_ushort
+          @height_unit = @file.read_ushort
+
+          @resource.data = self
+        end
+
+        def h_res_unit_name
+          RES_UNIT_NAMES.fetch(h_res_unit - 1, 'unknown')
+        end
+
+        def v_res_unit_name
+          RES_UNIT_NAMES.fetch(v_res_unit - 1, 'unknown')
+        end
+
+        def width_unit_name
+          UNIT_NAMES.fetch(width_unit - 1, 'unknown')
+        end
+
+        def height_unit_name
+          UNIT_NAMES.fetch(height_unit - 1, 'unknown')
+        end
+      end
+    end
+  end
+end