Add global mask parsing

examples/export_image.rb

@@ -1,7 +1,8 @@
 require 'benchmark'
 require './lib/psd'
 
-psd = PSD.new('examples/images/example.psd')
+file = ARGV[0] || 'examples/images/example.psd'
+psd = PSD.new(file)
 
 results = Benchmark.measure "Image exporting" do
   psd.image.save_as_png 'output.png'

lib/psd.rb

@@ -47,8 +47,6 @@ def initialize(file, opts={})
   # parse all sections of the PSD.
   def parse!
     header
-    PSD.logger.debug header.inspect
-
     resources
     layer_mask
     image if @opts[:parse_image]
@@ -65,7 +63,10 @@ def parsed?
 
   # Get the Header, parsing it if needed.
   def header
-    @header ||= Header.read(@file)
+    return @header if @header
+
+    @header = Header.read(@file)
+    PSD.logger.debug @header.inspect
   end
 
   # Get the Resources section, parsing if needed.
@@ -77,6 +78,8 @@ def resources
     @resources = Resources.new(@file)
     @resources.parse
 
+    PSD.logger.debug @resources.inspect
+
     return @resources.data
   end
 

lib/psd/image.rb

@@ -40,6 +40,8 @@ def initialize(file, header)
       @end_pos = @start_pos + @length
 
       @pixel_data = []
+
+      PSD.logger.debug "Image: #{width}x#{height}, length = #{@length}, mode = #{@header.mode_name}, position = #{@start_pos}"
     end
 
     # Begins parsing the image by first figuring out the compression format used, and then
@@ -49,9 +51,12 @@ def parse
 
       # ZIP not implemented
       if [2, 3].include?(@compression)
+        PSD.logger.debug "Warning: ZIP image compression not supported yet. Skipping."
         @file.seek @end_pos and return
       end
 
+      PSD.logger.debug "Compression: id = #{@compression}, name = #{COMPRESSIONS[@compression]}"
+
       parse_image_data!
 
       return self

lib/psd/image_formats/rle.rb

@@ -25,6 +25,7 @@ def parse_channel_data!
         line_index = 0
 
         channels.times do |i|
+          PSD.logger.debug "Parsing RLE channel ##{i}: position = #{chan_pos}, line = #{line_index}"
           chan_pos = decode_rle_channel(chan_pos, line_index)
           line_index += height
         end

lib/psd/layer_mask.rb

@@ -64,6 +64,8 @@ def parse
       layers.reverse!
       group_layers
 
+      parse_global_mask
+
       # Temporarily seek to the end of this section
       @file.seek finish
       end_section
@@ -102,5 +104,26 @@ def group_layers
         end
       end
     end
+
+    def parse_global_mask
+      length = @file.read_int
+      return if length == 0
+
+      mask_end = @file.tell + length
+      PSD.logger.debug "Global Mask: length = #{length}"
+
+      @global_mask = {}
+      @global_mask[:overlay_color_space] = @file.read_short
+      @global_mask[:color_components] = 4.times.map { |i| @file.read_short >> 8 }
+      @global_mask[:opacity] = @file.read_short
+
+      # 0 = color selected, 1 = color protected, 128 = use value per layer
+      @global_mask[:kind] = @file.read(1).bytes.to_a[0]
+
+      PSD.logger.debug @global_mask
+
+      # Filler zeros
+      @file.seek mask_end
+    end
   end
 end