Class: Jekyll::SrcsetTag

Inherits:
Liquid::Tag
  • Object
show all
Includes:
Magick
Defined in:
lib/jekyll/srcset/tag.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(tag_name, markup, _) ⇒ SrcsetTag

Returns a new instance of SrcsetTag.



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# File 'lib/jekyll/srcset/tag.rb', line 13

def initialize(tag_name, markup, _)
  @markup = markup
  super
end

Instance Attribute Details

#markup ⇒ Object

Returns the value of attribute markup.



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# File 'lib/jekyll/srcset/tag.rb', line 7

def markup
  @markup
end

Class Method Details

.optipng? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/jekyll/srcset/tag.rb', line 9

def self.optipng?
  @optinpng ||= system("which optipng")
end

Instance Method Details

#cache_dir(site) ⇒ Object 



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# File 'lib/jekyll/srcset/tag.rb', line 56

def cache_dir(site)
  config(site)['cache']
end

#config(site) ⇒ Object 



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# File 'lib/jekyll/srcset/tag.rb', line 48

def config(site)
  site.config['srcset'] || {}
end

#generate_image(site, src, attrs) ⇒ Object 



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# File 'lib/jekyll/srcset/tag.rb', line 60

def generate_image(site, src, attrs)
  cache = cache_dir(site)
  sha = cache && Digest::SHA1.hexdigest(attrs.sort.inspect + File.read(File.join(site.source, src)) + (optimize?(site) ? "optimize" : ""))
  if sha
    if File.exists?(File.join(cache, sha))
      img_attrs = JSON.parse(File.read(File.join(cache,sha,"json")))
      filename = img_attrs["src"].sub(/^\//, '')
      dest = File.join(site.dest, filename)
      FileUtils.mkdir_p(File.dirname(dest))
      FileUtils.cp(File.join(cache,sha,"img"), dest)

      site.config['keep_files'] << filename unless site.config['keep_files'].include?(filename)

      return img_attrs
    end
  end

  img = Image.read(File.join(site.source, src)).first
  img_attrs = {}

  if attrs["height"]
    scale = attrs["height"].to_f * (attrs["factor"] || 1) / img.rows.to_f
  elsif attrs["width"]
    scale = attrs["width"].to_f * (attrs["factor"] || 1) / img.columns.to_f
  else
    scale = attrs["factor"] || 1
  end

  img_attrs["height"] = attrs["height"] if attrs["height"]
  img_attrs["width"]  = attrs["width"]  if attrs["width"]
  img_attrs["src"] = src.sub(/(\.\w+)$/, "-#{img.columns}x#{img.rows}" + '\1')

  filename = img_attrs["src"].sub(/^\//, '')
  dest = File.join(site.dest, filename)
  FileUtils.mkdir_p(File.dirname(dest))

  unless File.exist?(dest)
    img.scale!(scale) if scale <= 1
    img.strip!
    img.write(dest)
    if dest.match(/\.png$/) && optimize?(site) && self.class.optipng?
      `optipng #{dest}`
    end
  end
  site.config['keep_files'] << filename unless site.config['keep_files'].include?(filename)
  # Keep files around for incremental builds in Jekyll 3
  site.regenerator.add(filename) if site.respond_to?(:regenerator)

  if sha
    FileUtils.mkdir_p(File.join(cache, sha))
    FileUtils.cp(dest, File.join(cache, sha, "img"))
    File.open(File.join(cache, sha, "json"), "w") do |f|
      f.write(JSON.generate(img_attrs))
    end
  end

  img_attrs
end

#optimize?(site) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/jekyll/srcset/tag.rb', line 52

def optimize?(site)
  config(site)['optipng']
end

#parse_options(markup, context) ⇒ Object 



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# File 'lib/jekyll/srcset/tag.rb', line 36

def parse_options(markup, context)
  options = {}
  markup.scan(/(\w+)=((?:"[^"]+")|(?:'[^']+')|[\w\.\_-]+)/) do |key,value|
    if (value[0..0] == "'" && value[-1..-1]) == "'" || (value[0..0] == '"' && value[-1..-1] == '"')
      options[key] = value[1..-2]
    else
      options[key] = context[value]
    end
  end
  options
end

#render(context) ⇒ Object 



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# File 'lib/jekyll/srcset/tag.rb', line 18

def render(context)
  options = parse_options(markup, context)

  return "Bad options to image_tag, syntax is: {% image_tag src=\"image.png\" width=\"100\"}" unless options["src"]
  return "Error resizing - can't set both width and height" if options["width"] && options["height"]

  site = context.registers[:site]
  img_attrs = generate_image(site, options["src"], options)

  srcset = []
  (1..3).each do |factor|
    srcset << {:factor => factor, :img => generate_image(site, options["src"], options.merge("factor" => factor))}
  end
  img_attrs["srcset"] = srcset.map {|i| "#{i[:img]["src"]} #{i[:factor]}x"}.join(", ")

  "<img #{options.merge(img_attrs).map {|k,v| "#{k}=\"#{v}\""}.join(" ")}>"
end