Added BUTTON_DEFAULT hash. This is a test snippet:

Shoes.app do
  style Shoes::Button, width: 100, height: 20
  10.times{|i| button i.to_s}
end

VERSION

@@ -1 +1 @@
-0.7.166
+0.7.167

lib/purple_shoes.rb

@@ -11,8 +11,9 @@ module Shoes
   DIR = Pathname.new(__FILE__).realpath.dirname.to_s
   FONTS = []
   LINK_DEFAULT = {underline: true}
-  BANNER_DEFAULT, TITLE_DEFAULT, SUBTITLE_DEFAULT, TAGLINE_DEFAULT, CAPTION_DEFAULT, PARA_DEFAULT, INSCRIPTION_DEFAULT = 
-    {}, {}, {}, {}, {}, {}, {}
+  %w[BANNER TITLE SUBTITLE TAGLINE CAPTION PARA INSCRIPTION BUTTON].each do |e|
+    eval "#{e}_DEFAULT = {}" 
+  end
   SHOES_VERSION = IO.read(File.join(DIR, '../VERSION')).chomp
   BASIC_ATTRIBUTES_DEFAULT = {left: 0, top: 0, width: 0, height: 0, angle: 0, curve: 0}
   SLOT_ATTRIBUTES_DEFAULT = {left: nil, top: nil, width: 1.0, height: 0}

lib/shoes/app.rb

@@ -195,6 +195,7 @@ def imagesize name
     end
 
     def buttonbase klass, name, args, &blk
+      args = eval("#{klass.to_s[7..-1].upcase}_DEFAULT").merge args
       args = basic_attributes args
       args[:block] = blk
       opt = if klass == Button then Swt::SWT::NULL

lib/shoes/style.rb

@@ -1,7 +1,7 @@
 class Shoes
   class App
     def style klass, args={}
-      if klass.superclass == Shoes::TextBlock or klass == Shoes::Link
+      if klass.superclass == Shoes::TextBlock or klass == Shoes::Link or klass == Shoes::Button
         eval("#{klass.to_s[7..-1].upcase}_DEFAULT").clear.merge! args
       end
     end

purple_shoes.gemspec

@@ -5,11 +5,11 @@
 
 Gem::Specification.new do |s|
   s.name = "purple_shoes"
-  s.version = "0.7.166"
+  s.version = "0.7.167"
 
   s.required_rubygems_version = Gem::Requirement.new(">= 0") if s.respond_to? :required_rubygems_version=
   s.authors = ["ashbb"]
-  s.date = "2012-05-16"
+  s.date = "2012-05-18"
   s.description = "Purple Shoes is one of colorful Shoes, written in JRuby and SWT."
   s.email = "ashbbb@gmail.com"
   s.executables = ["pshoes"]