如何在Ruby中将ppt转换为图像？

gem install redcarpet

require 'redcarpet'

markdown = "# Hello World!"
renderer = Redcarpet::Render::HTML.new
redcarpet = Redcarpet::Markdown.new(renderer)

pdf = redcarpet.render(markdown)

require 'pdftohtml'

converter = PDFToHTML.new
converter.parse("input.pdf", "output.html")

require 'rmagick'

image = Magick::Image.read("output.html").first
image.format = "PNG"
image.write("output.png")