Class: JekyllAutoThumbnails::Generator

Inherits:
Object
  • Object
show all
Defined in:
lib/jekyll-auto-thumbnails/generator.rb

Overview

Thumbnail generation via ImageMagick

Instance Method Summary collapse

Constructor Details

#initialize(config, site_source) ⇒ Generator

Initialize generator

Parameters:

  • config (Configuration) —

    configuration

  • site_source (String) —

    Jekyll site source directory



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# File 'lib/jekyll-auto-thumbnails/generator.rb', line 13

def initialize(config, site_source)
  @config = config
  @site_source = site_source
end

Instance Method Details

#build_thumbnail_filename(basename, digest, width, height, ext) ⇒ String

Build thumbnail filename

Parameters:

  • basename (String) —

    image basename (no extension)

  • digest (String) —

    6-char MD5 digest

  • width (Integer, nil) —

    width

  • height (Integer, nil) —

    height

  • ext (String) —

    file extension

Returns:

  • (String) —

    thumbnail filename



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# File 'lib/jekyll-auto-thumbnails/generator.rb', line 74

def build_thumbnail_filename(basename, digest, width, height, ext)
  width_str = width || ""
  height_str = height || ""
  "#{basename}_thumb-#{digest}-#{width_str}x#{height_str}#{ext}"
end

#generate(url, width, height) ⇒ String?

Generate thumbnail (with caching)

Parameters:

  • url (String) —

    image URL

  • width (Integer, nil) —

    target width

  • height (Integer, nil) —

    target height

Returns:

  • (String, nil) —

    path to cached thumbnail or nil if failed



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# File 'lib/jekyll-auto-thumbnails/generator.rb', line 31

def generate(url, width, height)
  # Resolve source file
  source_path = UrlResolver.to_filesystem_path(url, @site_source)
  return nil unless source_path && File.exist?(source_path)

  # Compute digest
  digest = DigestCalculator.short_digest(source_path)

  # Build thumbnail filename
  basename = File.basename(source_path, File.extname(source_path))
  ext = File.extname(source_path)
  thumb_filename = build_thumbnail_filename(basename, digest, width, height, ext)

  # Check cache
  cached_path = File.join(@config.cache_dir, thumb_filename)
  return cached_path if File.exist?(cached_path)

  # Generate
  FileUtils.mkdir_p(@config.cache_dir)
  success = shell_generate(source_path, cached_path, width, height)

  return nil unless success

  # Check if thumbnail is larger than original
  if File.size(cached_path) > File.size(source_path)
    Jekyll.logger.warn "AutoThumbnails:",
                       "Thumbnail larger than original (#{File.size(cached_path)} > #{File.size(source_path)}), " \
                       "deleting #{cached_path}"
    FileUtils.rm_f(cached_path)
    return nil
  end

  cached_path
end

#imagemagick_available? ⇒ Boolean

Check if ImageMagick is available (cross-platform)

Returns:

  • (Boolean) —

    true if ImageMagick (v6 or v7) is available



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# File 'lib/jekyll-auto-thumbnails/generator.rb', line 21

def imagemagick_available?
  ImageMagickWrapper.available?
end