Module: SafeImage::ImageMagickBackend

Defined in:
lib/safe_image/image_magick_backend.rb

Constant Summary collapse

DEFAULT_PROFILE = 
File.expand_path("RT_sRGB.icm", __dir__)
DECODERS = 
{
  "jpg" => "jpeg",
  "jpeg" => "jpeg",
  "png" => "png",
  "gif" => "gif",
  "webp" => "webp",
  "heic" => "heic",
  "heif" => "heic",
  "avif" => "heic",
  "ico" => "ico",
  "jxl" => "jxl"
}.freeze
IMAGEMAGICK_LIMIT_ARGS = 
[
  "-limit", "memory", "256MiB",
  "-limit", "map", "512MiB",
  "-limit", "disk", "1GiB",
  "-limit", "area", "128MP",
  "-limit", "time", "20",
  "-limit", "thread", "2"
].freeze
ALLOWED_FONTS = 
%w[NimbusSans-Regular DejaVu-Sans Liberation-Sans Arial Helvetica Adwaita-Sans].freeze

Class Method Summary collapse

Class Method Details

.convert(input:, output:, format:, quality: nil, timeout: Runner::DEFAULT_TIMEOUT) ⇒ Object 



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# File 'lib/safe_image/image_magick_backend.rb', line 111

def convert(input:, output:, format:, quality: nil, timeout: Runner::DEFAULT_TIMEOUT)
  command = convert_command
  input = PathSafety.ensure_imagemagick_input_file!(input)
  output = PathSafety.ensure_safe_output_path!(output).to_s
  output = PathSafety.ensure_imagemagick_safe!(output)
  ext = File.extname(input).delete_prefix(".").downcase
  decoder = DECODERS.fetch(ext) { raise UnsupportedFormatError, "unsupported ImageMagick input format: #{ext.inspect}" }
  normalized_format = format.to_s.downcase
  normalized_format = "jpg" if normalized_format == "jpeg"
  output_arg = output_spec(normalized_format, output)
  quality = validate_quality!(quality)

  argv = [command, *IMAGEMAGICK_LIMIT_ARGS, "#{decoder}:#{input}[0]", "-auto-orient", "-interlace", "none"]
  argv.concat(["-background", "white", "-flatten"]) if normalized_format == "jpg"
  argv.concat(["-quality", quality.to_s]) if quality
  argv << output_arg
  run_image_command(argv, output, ext, normalized_format, timeout)
end

.convert_command ⇒ Object 



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# File 'lib/safe_image/image_magick_backend.rb', line 276

def convert_command
  Runner.available?("magick") ? "magick" : Runner.resolve_executable!("convert") && "convert"
rescue UnsupportedFormatError
  raise UnsupportedFormatError, "ImageMagick convert/magick not available"
end

.convert_ico_to_png(input:, output:, timeout: Runner::DEFAULT_TIMEOUT) ⇒ Object 



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# File 'lib/safe_image/image_magick_backend.rb', line 134

def convert_ico_to_png(input:, output:, timeout: Runner::DEFAULT_TIMEOUT)
  command = convert_command
  input = PathSafety.ensure_imagemagick_input_file!(input)
  output = PathSafety.ensure_safe_output_path!(output).to_s
  output = PathSafety.ensure_imagemagick_safe!(output)
  argv = [command, *IMAGEMAGICK_LIMIT_ARGS, "ico:#{input}[-1]", "-auto-orient", "-background", "transparent", output_spec("png", output)]
  run_image_command(argv, output, "ico", "png", timeout)
end

.convert_to_jpeg(input:, output:, quality: nil, timeout: Runner::DEFAULT_TIMEOUT) ⇒ Object 



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# File 'lib/safe_image/image_magick_backend.rb', line 130

def convert_to_jpeg(input:, output:, quality: nil, timeout: Runner::DEFAULT_TIMEOUT)
  convert(input: input, output: output, format: "jpg", quality: quality, timeout: timeout)
end

.dominant_color(path, timeout: Runner::DEFAULT_TIMEOUT) ⇒ Object

Averages the whole image down to one pixel and reports it as an RRGGBB hex string, mirroring Discourse’s Upload#calculate_dominant_color!.

Raises:



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# File 'lib/safe_image/image_magick_backend.rb', line 173

def dominant_color(path, timeout: Runner::DEFAULT_TIMEOUT)
  command = convert_command
  path = PathSafety.ensure_imagemagick_input_file!(path)
  ext = File.extname(path).delete_prefix(".").downcase
  decoder = DECODERS.fetch(ext) { raise UnsupportedFormatError, "unsupported ImageMagick input format: #{ext.inspect}" }
  stdout, = Runner.run!(
    [
      command, *IMAGEMAGICK_LIMIT_ARGS, "#{decoder}:#{path}[0]",
      "-depth", "8",
      "-resize", "1x1",
      "-define", "histogram:unique-colors=true",
      "-format", "%c",
      "histogram:info:"
    ],
    timeout: timeout
  )

  # Typical output: `1: (110,116,93) #6F745E srgb(110,116,93)`. Alpha adds
  # two more hex digits; grayscale images report one channel (two digits,
  # four with alpha) instead of three.
  digits = stdout[/#(\h+)/, 1]
  hex =
    case digits&.length
    when 6, 8 then digits[0, 6]
    when 2, 4 then digits[0, 2] * 3
    end
  raise InvalidImageError, "could not parse dominant color from ImageMagick output: #{stdout.strip.inspect}" if hex.nil?
  hex.upcase
end

.downsize(input:, output:, dimensions:, format:, timeout: Runner::DEFAULT_TIMEOUT) ⇒ Object 



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# File 'lib/safe_image/image_magick_backend.rb', line 89

def downsize(input:, output:, dimensions:, format:, timeout: Runner::DEFAULT_TIMEOUT)
  command = convert_command

  input = PathSafety.ensure_imagemagick_input_file!(input)
  output = PathSafety.ensure_safe_output_path!(output).to_s
  output = PathSafety.ensure_imagemagick_safe!(output)
  ext = File.extname(input).delete_prefix(".").downcase
  decoder = DECODERS.fetch(ext) { raise UnsupportedFormatError, "unsupported ImageMagick input format: #{ext.inspect}" }
  dimensions = validate_dimensions!(dimensions)
  argv = [
    command, *IMAGEMAGICK_LIMIT_ARGS, "#{decoder}:#{input}[0]",
    "-auto-orient",
    "-gravity", "center",
    "-background", "transparent",
    "-interlace", "none",
    "-resize", dimensions,
  ]
  argv.concat(["-profile", DEFAULT_PROFILE]) if File.file?(DEFAULT_PROFILE)
  argv << output_spec(format, output)
  run_image_command(argv, output, ext, format, timeout)
end

.fix_orientation(input:, output: input, timeout: Runner::DEFAULT_TIMEOUT) ⇒ Object 



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# File 'lib/safe_image/image_magick_backend.rb', line 228

def fix_orientation(input:, output: input, timeout: Runner::DEFAULT_TIMEOUT)
  command = convert_command
  input = PathSafety.ensure_imagemagick_input_file!(input)
  output = PathSafety.ensure_safe_output_path!(output).to_s
  output = PathSafety.ensure_imagemagick_safe!(output)
  ext = File.extname(input).delete_prefix(".").downcase
  decoder = DECODERS.fetch(ext) { raise UnsupportedFormatError, "unsupported ImageMagick input format: #{ext.inspect}" }
  argv = [command, *IMAGEMAGICK_LIMIT_ARGS, "#{decoder}:#{input}[0]", "-auto-orient", output_spec(ext, output)]
  run_image_command(argv, output, ext, ext, timeout)
end

.frame_count(path, timeout: Runner::DEFAULT_TIMEOUT, max_pixels: nil) ⇒ Object

Raises:



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# File 'lib/safe_image/image_magick_backend.rb', line 143

def frame_count(path, timeout: Runner::DEFAULT_TIMEOUT, max_pixels: nil)
  raise UnsupportedFormatError, "ImageMagick identify not available" unless Runner.available?("identify")
  path = PathSafety.ensure_imagemagick_input_file!(path)
  ext = File.extname(path).delete_prefix(".").downcase
  decoder = DECODERS.fetch(ext) { raise UnsupportedFormatError, "unsupported ImageMagick input format: #{ext.inspect}" }
  stdout, = Runner.run!(["identify", *IMAGEMAGICK_LIMIT_ARGS, "-ping", "-format", "%w %h %n\n", "#{decoder}:#{path}"], timeout: timeout)
  width, height, frames = stdout.each_line.first.to_s.split.map(&:to_i)
  if max_pixels && width.to_i * height.to_i > Integer(max_pixels)
    raise LimitError, "image has #{width * height} pixels, exceeds #{max_pixels}"
  end
  frames.to_i
end

.letter_avatar(output:, size:, background_rgb:, letter:, pointsize:, font: "NimbusSans-Regular", timeout: Runner::DEFAULT_TIMEOUT) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/safe_image/image_magick_backend.rb', line 203

def letter_avatar(output:, size:, background_rgb:, letter:, pointsize:, font: "NimbusSans-Regular", timeout: Runner::DEFAULT_TIMEOUT)
  command = convert_command
  output = PathSafety.ensure_safe_output_path!(output).to_s
  output = PathSafety.ensure_imagemagick_safe!(output)
  rgb = Array(background_rgb).map { |v| Integer(v) }
  raise ArgumentError, "background_rgb must have three channels" unless rgb.length == 3
  glyph = letter.to_s.each_grapheme_cluster.first.to_s.gsub("%", "%%")
  font_name = font.to_s
  raise ArgumentError, "unsupported font: #{font_name.inspect}" unless ALLOWED_FONTS.include?(font_name)

  argv = [
    command, *IMAGEMAGICK_LIMIT_ARGS,
    "-size", "#{Integer(size)}x#{Integer(size)}",
    "xc:rgb(#{rgb[0]},#{rgb[1]},#{rgb[2]})",
    "-pointsize", Integer(pointsize).to_s,
    "-fill", "#FFFFFFCC",
    "-font", font_name,
    "-gravity", "Center",
    "-annotate", "-0+34", glyph,
    "-depth", "8",
    output_spec("png", output)
  ]
  run_image_command(argv, output, "generated", "png", timeout)
end

.orientation(path, timeout: Runner::DEFAULT_TIMEOUT) ⇒ Object 



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# File 'lib/safe_image/image_magick_backend.rb', line 156

def orientation(path, timeout: Runner::DEFAULT_TIMEOUT)
  raise UnsupportedFormatError, "ImageMagick identify not available" unless Runner.available?("identify")
  path = PathSafety.ensure_imagemagick_input_file!(path)
  ext = File.extname(path).delete_prefix(".").downcase
  decoder = DECODERS.fetch(ext) { raise UnsupportedFormatError, "unsupported ImageMagick input format: #{ext.inspect}" }
  stdout, = Runner.run!(
    ["identify", *IMAGEMAGICK_LIMIT_ARGS, "-ping", "-format", "%[EXIF:Orientation]", "#{decoder}:#{path}[0]"],
    timeout: timeout
  )
  value = stdout.to_s.strip
  value.empty? ? 1 : value.to_i
rescue CommandError
  1
end

.output_spec(format, output) ⇒ Object

Raises:



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# File 'lib/safe_image/image_magick_backend.rb', line 239

def output_spec(format, output)
  ext = File.extname(output).delete_prefix(".").downcase
  ext = "jpg" if ext == "jpeg"
  normalized = format.to_s.downcase
  normalized = "jpg" if normalized == "jpeg"
  raise UnsupportedFormatError, "output extension #{ext.inspect} does not match format #{normalized.inspect}" unless ext == normalized

  coder = {
    "jpg" => "jpeg",
    "png" => "png",
    "gif" => "gif",
    "webp" => "webp",
    "avif" => "avif",
    "ico" => "ico",
    "jxl" => "jxl"
  }.fetch(normalized) { raise UnsupportedFormatError, "unsupported ImageMagick output format: #{normalized.inspect}" }
  "#{coder}:#{output}"
end

.probe(path, timeout: Runner::DEFAULT_TIMEOUT, max_pixels: nil) ⇒ Object

Raises:



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# File 'lib/safe_image/image_magick_backend.rb', line 32

def probe(path, timeout: Runner::DEFAULT_TIMEOUT, max_pixels: nil)
  raise UnsupportedFormatError, "ImageMagick identify not available" unless Runner.available?("identify")
  path = PathSafety.ensure_imagemagick_input_file!(path)
  ext = File.extname(path).delete_prefix(".").downcase
  decoder = DECODERS.fetch(ext) { raise UnsupportedFormatError, "unsupported ImageMagick input format: #{ext.inspect}" }
  stdout, = Runner.run!(["identify", *IMAGEMAGICK_LIMIT_ARGS, "-ping", "-format", "%m %w %h %n\n", "#{decoder}:#{path}"], timeout: timeout)
  _magick_format, width, height, frames = stdout.each_line.first.to_s.split
  width = width.to_i
  height = height.to_i
  if max_pixels && width * height > Integer(max_pixels)
    raise LimitError, "image has #{width * height} pixels, exceeds #{max_pixels}"
  end
  { input_format: ext == "jpeg" ? "jpg" : ext, width: width, height: height, frames: frames.to_i, duration_ms: 0.0 }
end

.resize_like(input:, output:, width:, height:, format:, quality:, crop: false, timeout: Runner::DEFAULT_TIMEOUT) ⇒ Object 



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# File 'lib/safe_image/image_magick_backend.rb', line 51

def resize_like(input:, output:, width:, height:, format:, quality:, crop: false, timeout: Runner::DEFAULT_TIMEOUT)
  command = convert_command

  input = PathSafety.ensure_imagemagick_input_file!(input)
  output = PathSafety.ensure_safe_output_path!(output).to_s
  output = PathSafety.ensure_imagemagick_safe!(output)
  ext = File.extname(input).delete_prefix(".").downcase
  decoder = DECODERS.fetch(ext) { raise UnsupportedFormatError, "unsupported ImageMagick input format: #{ext.inspect}" }

  quality = validate_quality!(quality)
  argv = [command, *IMAGEMAGICK_LIMIT_ARGS, "#{decoder}:#{input}[0]", "-auto-orient"]
  if crop == :north
    argv.concat([
      "-gravity", "north",
      "-background", "transparent",
      "-thumbnail", "#{Integer(width)}x#{Integer(height)}^",
      "-crop", "#{Integer(width)}x#{Integer(height)}+0+0",
      "-unsharp", "2x0.5+0.7+0",
      "-interlace", "none"
    ])
  else
    argv.concat([
      "-gravity", "center",
      "-background", "transparent",
      "-thumbnail", "#{Integer(width)}x#{Integer(height)}^",
      "-extent", "#{Integer(width)}x#{Integer(height)}",
      "-interpolate", "catrom",
      "-unsharp", "2x0.5+0.7+0",
      "-interlace", "none"
    ])
  end
  argv.concat(["-profile", DEFAULT_PROFILE]) if File.file?(DEFAULT_PROFILE)
  argv.concat(["-quality", quality.to_s]) if quality
  argv << output_spec(format, output)

  run_image_command(argv, output, ext, format, timeout)
end

.run_image_command(argv, output, input_format, output_format, timeout) ⇒ Object 



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# File 'lib/safe_image/image_magick_backend.rb', line 282

def run_image_command(argv, output, input_format, output_format, timeout)
  started = Process.clock_gettime(Process::CLOCK_MONOTONIC)
  Runner.run!(argv, timeout: timeout)
  duration_ms = (Process.clock_gettime(Process::CLOCK_MONOTONIC) - started) * 1000

  # Output dimensions via the fast native header read, or identify when
  # libvips is not installed (this backend must work without it).
  info = VipsGlue.available? ? Native.probe(output) : probe(output)
  {
    input_format: input_format == "jpeg" ? "jpg" : input_format,
    output_format: output_format == "jpeg" ? "jpg" : output_format,
    width: info.fetch(:width),
    height: info.fetch(:height),
    duration_ms: duration_ms
  }
end

.thumbnail(input:, output:, width:, height:, format:, quality:, timeout: Runner::DEFAULT_TIMEOUT) ⇒ Object 



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# File 'lib/safe_image/image_magick_backend.rb', line 47

def thumbnail(input:, output:, width:, height:, format:, quality:, timeout: Runner::DEFAULT_TIMEOUT)
  resize_like(input: input, output: output, width: width, height: height, format: format, quality: quality, crop: :centre, timeout: timeout)
end

.validate_dimensions!(dimensions) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/safe_image/image_magick_backend.rb', line 265

def validate_dimensions!(dimensions)
  dimensions = dimensions.to_s
  patterns = [
    /\A\d+(?:\.\d+)?%\z/,
    /\A\d+x\d+[!<>^]?\z/,
    /\A\d+@\z/
  ]
  raise ArgumentError, "unsupported ImageMagick geometry: #{dimensions.inspect}" unless patterns.any? { |pattern| pattern.match?(dimensions) }
  dimensions
end

.validate_quality!(quality) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/safe_image/image_magick_backend.rb', line 258

def validate_quality!(quality)
  return nil if quality.nil?
  quality = Integer(quality)
  raise ArgumentError, "quality must be 1..100" unless (1..100).cover?(quality)
  quality
end