chunky_png.rb in chunky_png-1.3.9

- old
+ new

@@ -5,11 +5,11 @@
 require 'enumerator'
 
 # ChunkyPNG - the pure ruby library to access PNG files.
 #
 # The ChunkyPNG module defines some constants that are used in the
-# PNG specification, specifies some exception classes, and serves as 
+# PNG specification, specifies some exception classes, and serves as
 # a namespace for all the other modules and classes in this library.
 #
 # {ChunkyPNG::Image}::      class to represent PNG images, including metadata.
 # {ChunkyPNG::Canvas}::     class to represent the image's canvas.
 # {ChunkyPNG::Color}::      module to work with color values.
@@ -25,46 +25,56 @@
 
   ###################################################
   # PNG international standard defined constants
   ###################################################
 
-  # Indicates that the PNG image uses grayscale colors, i.e. only a 
+  # Indicates that the PNG image uses grayscale colors, i.e. only a
   # single teint channel.
   # @private
   COLOR_GRAYSCALE       = 0
-  
+
   # Indicates that the PNG image uses true color, composed of a red
   # green and blue channel.
   # @private
   COLOR_TRUECOLOR       = 2
-  
+
   # Indicates that the PNG image uses indexed colors, where the values
   # point to colors defined on a palette.
   # @private
   COLOR_INDEXED         = 3
-  
+
   # Indicates that the PNG image uses grayscale colors with opacity, i.e.
   # a teint channel with an alpha channel.
   # @private
   COLOR_GRAYSCALE_ALPHA = 4
-  
-  # Indicates that the PNG image uses true color with opacity, composed of 
+
+  # Indicates that the PNG image uses true color with opacity, composed of
   # a red, green and blue channel, and an alpha value.
   # @private
   COLOR_TRUECOLOR_ALPHA = 6
 
   # Indicates that the PNG specification's default compression
   # method is used (Zlib/Deflate)
   # @private
   COMPRESSION_DEFAULT   = 0
 
+  # Indicates that the PNG chunk content is not compressed
+  # flag used in iTXt chunk
+  # @private
+  UNCOMPRESSED_CONTENT  = 0
+
+  # Indicates that the PNG chunk content is compressed
+  # flag used in iTXt chunk
+  # @private
+  COMPRESSED_CONTENT    = 1
+
   # Indicates that the image does not use interlacing.
   # @private
   INTERLACING_NONE      = 0
-  
+
   # Indicates that the image uses Adam7 interlacing.
-  # @private  
+  # @private
   INTERLACING_ADAM7     = 1
 
   ### Filter method constants
 
   # Indicates that the PNG specification's default filtering are
@@ -73,23 +83,23 @@
   FILTERING_DEFAULT     = 0
 
   # Indicates that no filtering is used for the scanline.
   # @private
   FILTER_NONE           = 0
-  
+
   # Indicates that SUB filtering is used for the scanline.
   # @private
   FILTER_SUB            = 1
-  
+
   # Indicates that UP filtering is used for the scanline.
   # @private
   FILTER_UP             = 2
-  
+
   # Indicates that AVERAGE filtering is used for the scanline.
   # @private
   FILTER_AVERAGE        = 3
-  
+
   # Indicates that PAETH filtering is used for the scanline.
   # @private
   FILTER_PAETH          = 4
 
   ###################################################
@@ -102,19 +112,23 @@
 
   # Exception that is raised for an unsupported PNG image.
   class NotSupported < ChunkyPNG::Exception
   end
 
-  # Exception that is raised if the PNG signature is not encountered at the 
+  # Exception that is raised if the PNG signature is not encountered at the
   # beginning of the file.
   class SignatureMismatch < ChunkyPNG::Exception
   end
 
   # Exception that is raised if the CRC check for a block fails
   class CRCMismatch < ChunkyPNG::Exception
   end
 
+  # Exception that is raised if an tTXt chunk does not contain valid UTF-8 data.
+  class InvalidUTF8 < ChunkyPNG::Exception
+  end
+
   # Exception that is raised if an expectation fails.
   class ExpectationFailed < ChunkyPNG::Exception
   end
 
   # Exception that is raised if an expectation fails.
@@ -127,18 +141,18 @@
   end
 
   def self.force_binary(str)
     str.respond_to?(:force_encoding) ? str.force_encoding('BINARY') : str
   end
-  
+
   # Empty byte array. This basically is an empty string, but with the encoding
   # set correctly to ASCII-8BIT (binary) in Ruby 1.9.
   # @return [String] An empty string, with encoding set to binary in Ruby 1.9
   # @private
   EMPTY_BYTEARRAY = force_binary(String.new).freeze
 
   # Null-byte, with the encoding set correctly to ASCII-8BIT (binary) in Ruby 1.9.
-  # @return [String] A binary string, consisting of one NULL-byte. 
+  # @return [String] A binary string, consisting of one NULL-byte.
   # @private
   EXTRA_BYTE = force_binary(String.new("\0")).freeze
 end
 
 require 'chunky_png/version'