Class: Jekyll::ResponsiveImage::Tag

Inherits:
Liquid::Tag
  • Object
show all
Defined in:
lib/jekyll/responsive_image.rb

Constant Summary collapse

DEFAULT_QUALITY = 
85

Instance Method Summary collapse

Constructor Details

#initialize(tag_name, markup, tokens) ⇒ Tag

Returns a new instance of Tag.



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# File 'lib/jekyll/responsive_image.rb', line 9

def initialize(tag_name, markup, tokens)
  super

  @attributes = {}
  @markup = markup

  @markup.scan(::Liquid::TagAttributes) do |key, value|
    # Strip quotes from around attribute values
    @attributes[key] = value.gsub(/^['"]|['"]$/, '')
  end
end

Instance Method Details

#ensure_output_dir_exists!(dir) ⇒ Object 



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# File 'lib/jekyll/responsive_image.rb', line 77

def ensure_output_dir_exists!(dir)
  unless Dir.exists?(dir)
    Jekyll.logger.info "Creating output directory #{dir}"
    Dir.mkdir(dir)
  end
end

#needs_resizing?(img, width) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/jekyll/responsive_image.rb', line 73

def needs_resizing?(img, width)
  img.columns > width
end

#render(context) ⇒ Object 



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# File 'lib/jekyll/responsive_image.rb', line 84

def render(context)
  config = context.registers[:site].config['responsive_image']
  config['output_dir'] ||= 'assets/resized'
  config['sizes'] ||= []

  @attributes['template'] ||= config['template']
  @attributes['resized'] = resize_image(@attributes['path'], config)

  partial = File.read(@attributes['template'])
  template = Liquid::Template.parse(partial)

  template.render!(@attributes)
end

#resize_image(path, config) ⇒ Object 



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# File 'lib/jekyll/responsive_image.rb', line 21

def resize_image(path, config)
  sizes = config['sizes']

  return if sizes.empty?

  output_dir = config['output_dir']
  ensure_output_dir_exists!(output_dir)

  resized = []
  img = Magick::Image::read(path).first

  sizes.each do |size|
    width = size['width']
    ratio = width.to_f / img.columns.to_f
    height = (img.rows.to_f * ratio).round

    filename = resized_filename(path, width, height)
    newpath = "#{output_dir}/#{filename}"

    next unless needs_resizing?(img, width)

    resized.push({
      'width'  => width,
      'height' => height,
      'path'   => newpath,
    })

    # Don't resize images more than once
    next if File.exists?(newpath)

    Jekyll.logger.info "Generating #{newpath}"

    i = img.scale(ratio)
    i.write(newpath) do |f|
      f.quality = size['quality'] || DEFAULT_QUALITY
    end

    i.destroy!
  end

  resized
end

#resized_filename(path, width, height) ⇒ Object

Insert resize information into a file path

resized_filename(/foo/bar/file.name.jpg, 500, 300)
  => /foo/bar/file.name-500x300.jpg



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# File 'lib/jekyll/responsive_image.rb', line 69

def resized_filename(path, width, height)
  File.basename(path).sub(/\.([^.]+)$/, "-#{width}x#{height}.\\1")
end