Samples: add helper methods for graph paper look-and-feel

lib/squib/sample_helpers.rb

@@ -0,0 +1,34 @@
+module Squib
+
+  # Some helper methods specifically for samples
+  #@api private
+  #:nodoc:
+  class Deck
+
+    # Draw graph paper for samples
+    def draw_graph_paper(width, height)
+      background color: 'white'
+      grid width: 50,  height: 50,  stroke_color: '#0066FF', stroke_width: 1.5
+      grid width: 200, height: 200, stroke_color: '#0066FF', stroke_width: 3, x: 50, y: 50
+      (50..height).step(200) do |y|
+        text str: "y=#{y}", x: 3, y: y - 18, font: 'Open Sans, Sans 10'
+      end
+    end
+
+    # Define a set of samples on some graph paper
+    def sample(str)
+      @sample_x ||= 100
+      @sample_y ||= 100
+      rect x: 460, y: @sample_y - 40, width: 600,
+           height: 180, fill_color: '#FFD655', stroke_color: 'black', radius: 15
+      text str: str, x: 460, y: @sample_y - 40,
+           width: 540, height: 180,
+           valign: 'middle', align: 'center',
+           font: 'Times New Roman,Serif 24'
+      yield @sample_x, @sample_y
+      @sample_y += 200
+    end
+
+  end
+
+end