Add support for charty (#18)

* ✨ Add support for charty

* 🎨 Check nil or extname and add gem deps

Author: kozo2

exe/rubydown

@@ -3,7 +3,7 @@
 require 'kramdown'
 require 'erb'
 require 'stringio'
-
+require 'base64'
 require 'optparse'
 
 require 'rubydown'
@@ -62,6 +62,9 @@ class EvalDoc < Kramdown::Document
     case
     when eval_result.respond_to?(:to_html)
       Kramdown::Document.new(eval_result.to_html, input: :html).root
+    when eval_result.instance_of?(File) && File.extname(eval_result.path) == ".png"
+      img_b64 = Base64.encode64(File.binread(eval_result.path))
+      Kramdown::Document.new("<img src='data:image/png;base64,#{img_b64}' />", input: :html).root
     else
       text_result_el(stdout_string + "=> #{eval_result}")
     end

lib/rubydown.rb

@@ -5,6 +5,7 @@
 require 'numo/gnuplot'
 require 'base64'
 require 'tempfile'
+require 'charty'
 
 
 class Numo::NArray
@@ -29,6 +30,17 @@ def to_html
   end
 end
 
+Charty::RenderContext.prepend Module.new {
+  def render(filename=nil)
+    super
+    if filename.nil?
+      p "The image could not be rendered. In the environment without IRuby, the file name for the charty render method is required."
+    else
+      File.open(filename)
+    end
+  end
+}
+
 module Rubydown
   class RbMarkPlot < Numo::Gnuplot
     def plot(*args)

rubydown.gemspec

@@ -40,6 +40,8 @@ Gem::Specification.new do |spec|
   spec.add_dependency "numo-narray", "~> 0.9.1"
   spec.add_dependency "numo-gnuplot", "~> 0.2.4"
   spec.add_dependency "rbplotly", "~> 0.1.2"
+  spec.add_dependency "charty", "0.1.1.dev"
+  spec.add_dependency "matplotlib", "~> 1.0.0"
 
   spec.add_development_dependency "bundler", "~> 1.17"
   spec.add_development_dependency "rake", "~> 10.0"