102 lines
2.6 KiB
Ruby
102 lines
2.6 KiB
Ruby
require 'jekyll'
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require 'rmagick'
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module Jekyll
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class ResponsiveImage
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class Tag < Liquid::Tag
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DEFAULT_QUALITY = 85
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def initialize(tag_name, markup, tokens)
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super
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@attributes = {}
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@markup = markup
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@markup.scan(::Liquid::TagAttributes) do |key, value|
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# Strip quotes from around attribute values
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@attributes[key] = value.gsub(/^['"]|['"]$/, '')
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end
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end
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def resize_image(path, config)
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sizes = config['sizes']
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return if sizes.empty?
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output_dir = config['output_dir']
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ensure_output_dir_exists!(output_dir)
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resized = []
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img = Magick::Image::read(path).first
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sizes.each do |size|
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width = size['width']
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ratio = width.to_f / img.columns.to_f
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height = (img.rows.to_f * ratio).round
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filename = resized_filename(path, width, height)
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newpath = "#{output_dir}/#{filename}"
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next unless needs_resizing?(img, width)
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resized.push({
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'width' => width,
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'height' => height,
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'path' => newpath,
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})
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# Don't resize images more than once
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next if File.exists?(newpath)
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Jekyll.logger.info "Generating #{newpath}"
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i = img.scale(ratio)
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i.write(newpath) do |f|
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f.quality = size['quality'] || DEFAULT_QUALITY
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end
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i.destroy!
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end
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resized
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end
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# Insert resize information into a file path
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#
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# resized_filename(/foo/bar/file.name.jpg, 500, 300)
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# => /foo/bar/file.name-500x300.jpg
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#
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def resized_filename(path, width, height)
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File.basename(path).sub(/\.([^.]+)$/, "-#{width}x#{height}.\\1")
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end
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def needs_resizing?(img, width)
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img.columns > width
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end
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def ensure_output_dir_exists!(dir)
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unless Dir.exists?(dir)
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Jekyll.logger.info "Creating output directory #{dir}"
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Dir.mkdir(dir)
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end
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end
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def render(context)
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config = context.registers[:site].config['responsive_image']
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config['output_dir'] ||= 'assets/resized'
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config['sizes'] ||= []
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@attributes['template'] ||= config['template']
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@attributes['resized'] = resize_image(@attributes['path'], config)
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partial = File.read(@attributes['template'])
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template = Liquid::Template.parse(partial)
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template.render!(@attributes)
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end
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end
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end
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end
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Liquid::Template.register_tag('responsive_image', Jekyll::ResponsiveImage::Tag)
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