PDF::Writer：PDF::Writer::StrokeStyle::DEFAULT

require 'pdf/writer'

p PDF::Writer::StrokeStyle::DEFAULT
p PDF::Writer::StrokeStyle::SOLID_LINE

で、

#<PDF::Writer::StrokeStyle:0x401f5b54 @cap=:butt, @miter_limit=nil, @width=1, @dash={:pattern=>[], :phase=>0}, @join=:miter>
{:pattern=>[], :phase=>0}