Hacked together a basic example to work from

lib/squib/graphics/cairo_context_wrapper.rb

@@ -23,7 +23,7 @@ module Squib
         :set_source, :scale, :render_rsvg_handle, :circle, :triangle, :line_to,
         :operator=, :show_page, :clip, :transform, :mask, :create_pango_layout,
         :antialias=, :curve_to, :matrix, :matrix=, :identity_matrix, :pango_layout_path,
-        :stroke_preserve
+        :stroke_preserve, :target
 
       # :nodoc:
       # @api private

lib/squib/graphics/hand.rb

@@ -0,0 +1 @@
+hand.rb

samples/hand.rb

@@ -2,19 +2,44 @@ require 'squib'
 
 # Built-in layouts are easy to use and extend
 Squib::Deck.new(cards: 8, layout: 'playing-card.yml') do
-  # background color: :white
+  background color: :white
-  # rect x: 37, y: 37, width: 750, height: 1050, fill_color: :black
+  rect x: 37, y: 37, width: 750, height: 1050, fill_color: :black, radius: 25
-  # rect x: 75, y: 75, width: 675, height: 975, fill_color: :white
+  rect x: 75, y: 75, width: 675, height: 975, fill_color: :white, radius: 20
-  # text str: ('A'..'H').to_a, layout: :bonus_ul, font: 'Sans bold 100'
+  text str: ('A'..'H').to_a, layout: :bonus_ul, font: 'Sans bold 100'
-  # def helper(a)
+  # hand range: :all,
-  #   puts a
+  #      center_x: :auto, center_y: :auto,
-  # end
+  #      angle_start: 0, angle_end: Math::PI,
-  # helper('abc')
+  #      width: :auto, height: :auto
-  # helper('def')
-  # # hand range: :all,
-  # #      center_x: :auto, center_y: :auto,
-  # #      angle_start: 0, angle_end: Math::PI,
-  # #      width: :auto, height: :auto,
   # save_png prefix: 'hand_'
+  #
+  # Here's the hacky version
+  # So much hardcoded magic to get this to work. Math is hard.
+  # Idea: getting the final image surface extents is hard math for me. Maybe
+  #       just put it on a recording surface, then get the extents.
+  #       Can't seem to create unbounded surfaces in rcairo, so just make it
+  #       massively large enough. Paint the recording surface with proper margins
+  #       at the end
+  cxt = Cairo::Context.new(Cairo::ImageSurface.new(2 * 1.3 * height, 2 * 1.3 * height))
+  cxt.translate( 1.3 * height , 1.3 * height)
+  cxt.rotate(Math::PI / -4.0)
+  cxt.translate( -1.3 * height, -1.3 * height)
+  cxt.translate(500, 500) # I don't even know why I need this
+  angle = (Math::PI / 2.0) / cards.size
+  radius_x, radius_y = 0 + (width / 2.0), 1.3 * height
+  each_with_index do |card, i|
+    cxt.translate(radius_x, radius_y)
+    cxt.rotate(angle)
+    cxt.translate(-radius_x, -radius_y)
+    card.use_cairo do |card_cxt|
+      cxt.rounded_rectangle(37, 37, 825-75, 1125-75, 25, 25)
+      cxt.clip
+      cxt.set_source(card_cxt.target)
+      cxt.paint
+      cxt.reset_clip
+    end
+  end
+
+  cxt.target.write_to_png('_output/hand.png')
+
 end