@@ -140,10 +140,12 @@ module Prawn color_space = case jpg.channels when 1 :DeviceGray + when 3 + :DeviceRGB when 4 :DeviceCMYK else - :DeviceRGB + raise ArgumentError, 'JPG uses an unsupported number of channels' end obj = ref(:Type => :XObject, :Subtype => :Image, @@ -153,6 +155,14 @@ module Prawn :Width => jpg.width, :Height => jpg.height, :Length => data.size ) + + # add extra decode params for CMYK images. By swapping the + # min and max values from the default, we invert the colours. See + # section 4.8.4 of the spec. + if color_space == :DeviceCMYK + obj.data[:Decode] = [ 1.0, 0.0, 1.0, 0.0, 1.0, 0.0, 1.0, 0.0 ] + end + obj << data return obj end lib/prawn/images.rb 0c97cc776ab65adc50e317768a6c3cc246cca9ed James Healy jimmy@deefa.com http://github.com/sandal/prawn/commit/827887ea2e1ca845a07af46241c83050440ae35e 827887ea2e1ca845a07af46241c83050440ae35e 2008-10-31T08:32:37-07:00 2008-10-31T08:32:37-07:00 Set an explicit Decode Array for CMYK jpg images - see section 4.8.4 of the spec. We're swapping Dmin and Dmax to invert colours. 0a660c4ca4117d40dc34d905ef10a0fae73443dc James Healy jimmy@deefa.com