Module: SafeImage::ImageMagickBackend

Defined in:
lib/safe_image/image_magick_backend.rb

Constant Summary collapse

DEFAULT_PROFILE = 
File.expand_path("RT_sRGB.icm", __dir__)
IMAGEMAGICK_LIMIT_ARGS = 
%w[
  -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 140

def convert(input:, output:, format:, quality: nil, timeout: Runner::DEFAULT_TIMEOUT)
  command = convert_command
  input, ext, input_arg = imagemagick_input(input, frame: 0)
  normalized_format = Formats.normalize(format)
  output, output_arg = imagemagick_output(normalized_format, output)
  quality = validate_quality!(quality)

  argv = [command, *IMAGEMAGICK_LIMIT_ARGS, input_arg, "-auto-orient", "-interlace", "none"]
  argv.concat(%w[-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, read: [input])
end

.convert_command ⇒ Object 



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# File 'lib/safe_image/image_magick_backend.rb', line 333

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

Raises:



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# File 'lib/safe_image/image_magick_backend.rb', line 154

def convert_ico_to_png(input:, output:, timeout: Runner::DEFAULT_TIMEOUT)
  command = convert_command
  input, ext, input_arg = imagemagick_input(input, frame: -1)
  raise UnsupportedFormatError, "convert_favicon_to_png requires ico input, got #{ext.inspect}" unless ext == "ico"

  output, output_arg = imagemagick_output("png", output)
  argv = [command, *IMAGEMAGICK_LIMIT_ARGS, input_arg, "-auto-orient", "-background", "transparent", output_arg]
  run_image_command(argv, output, "ico", "png", timeout, read: [input])
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.



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# File 'lib/safe_image/image_magick_backend.rb', line 206

def dominant_color(path, timeout: Runner::DEFAULT_TIMEOUT)
  command = convert_command
  input, _ext, input_arg = imagemagick_input(path, frame: 0)
  stdout, =
    Runner.run!(
      [
        command,
        *IMAGEMAGICK_LIMIT_ARGS,
        input_arg,
        "-depth",
        "8",
        "-resize",
        "1x1",
        "-define",
        "histogram:unique-colors=true",
        "-format",
        "%c",
        "histogram:info:"
      ],
      timeout: timeout,
      read: [input]
    )

  # 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
      digits[0, 6]
    when 2, 4
      digits[0, 2] * 3
    end
  if hex.nil?
    raise InvalidImageError, "could not parse dominant color from ImageMagick output: #{stdout.strip.inspect}"
  end
  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 115

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

  input, ext, input_arg = imagemagick_input(input, frame: 0)
  output, output_arg = imagemagick_output(format, output)
  dimensions = validate_dimensions!(dimensions)
  argv = [
    command,
    *IMAGEMAGICK_LIMIT_ARGS,
    input_arg,
    "-auto-orient",
    "-gravity",
    "center",
    "-background",
    "transparent",
    "-interlace",
    "none",
    "-resize",
    dimensions
  ]
  argv.concat(["-profile", DEFAULT_PROFILE]) if File.file?(DEFAULT_PROFILE)
  argv << output_arg
  run_image_command(argv, output, ext, format, timeout, read: [input])
end

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



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# File 'lib/safe_image/image_magick_backend.rb', line 289

def fix_orientation(input:, output:, timeout: Runner::DEFAULT_TIMEOUT)
  command = convert_command
  input, ext, input_arg = imagemagick_input(input, frame: 0)
  output, output_arg = imagemagick_output(ext, output)
  argv = [command, *IMAGEMAGICK_LIMIT_ARGS, input_arg, "-auto-orient", output_arg]
  run_image_command(argv, output, ext, ext, timeout, read: [input])
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 164

def frame_count(path, timeout: Runner::DEFAULT_TIMEOUT, max_pixels: nil)
  raise UnsupportedFormatError, "ImageMagick identify not available" unless Runner.available?("identify")
  input, _ext, input_arg = imagemagick_input(path, frame: nil)
  stdout, =
    Runner.run!(
      ["identify", *IMAGEMAGICK_LIMIT_ARGS, "-ping", "-format", "%w %h %n\n", input_arg],
      timeout: timeout,
      read: [input]
    )
  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

.imagemagick_input(input, frame:) ⇒ Object 



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# File 'lib/safe_image/image_magick_backend.rb', line 297

def imagemagick_input(input, frame:)
  input = PathSafety.ensure_imagemagick_input_file!(input)
  ext = Formats.extension(input)
  decoder = Formats.imagemagick_decoder(ext)
  frame_suffix = frame.nil? ? "" : "[#{Integer(frame)}]"
  [input, ext, "#{decoder}:#{input}#{frame_suffix}"]
end

.imagemagick_output(format, output) ⇒ Object 



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# File 'lib/safe_image/image_magick_backend.rb', line 305

def imagemagick_output(format, output)
  output = PathSafety.ensure_safe_output_path!(output).to_s
  output = PathSafety.ensure_imagemagick_safe!(output)
  normalized = Formats.normalize(format)
  ext = Formats.extension(output)
  unless ext == normalized
    raise UnsupportedFormatError, "output extension #{ext.inspect} does not match format #{normalized.inspect}"
  end

  [output, "#{Formats.imagemagick_output_coder(normalized)}:#{output}"]
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 246

def letter_avatar(
  output:,
  size:,
  background_rgb:,
  letter:,
  pointsize:,
  font: "NimbusSans-Regular",
  timeout: Runner::DEFAULT_TIMEOUT
)
  command = convert_command
  output, output_arg = imagemagick_output("png", 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
  if ALLOWED_FONTS.none? { |candidate| candidate == font_name }
    raise ArgumentError, "unsupported font: #{font_name.inspect}"
  end

  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_arg
  ]
  run_image_command(argv, output, "generated", "png", timeout)
end

.missing_orientation_property?(error) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/safe_image/image_magick_backend.rb', line 197

def missing_orientation_property?(error)
  return false unless error.category == :exit_status

  detail = [error.stderr, error.stdout, error.message].join("\n")
  detail.match?(/EXIF:Orientation|unknown image property|no such (?:property|attribute)|undefined/i)
end

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



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# File 'lib/safe_image/image_magick_backend.rb', line 180

def orientation(path, timeout: Runner::DEFAULT_TIMEOUT)
  raise UnsupportedFormatError, "ImageMagick identify not available" unless Runner.available?("identify")
  input, _ext, input_arg = imagemagick_input(path, frame: 0)
  stdout, =
    Runner.run!(
      ["identify", *IMAGEMAGICK_LIMIT_ARGS, "-ping", "-format", "%[EXIF:Orientation]", input_arg],
      timeout: timeout,
      read: [input]
    )
  value = stdout.to_s.strip
  value.empty? ? 1 : value.to_i
rescue CommandError => e
  raise unless missing_orientation_property?(e)

  1
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")
  input, ext, input_arg = imagemagick_input(path, frame: nil)
  stdout, =
    Runner.run!(
      ["identify", *IMAGEMAGICK_LIMIT_ARGS, "-ping", "-format", "%m %w %h %n\n", input_arg],
      timeout: timeout,
      read: [input]
    )
  _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: Formats.normalize(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 63

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

  input, ext, input_arg = imagemagick_input(input, frame: 0)
  output, output_arg = imagemagick_output(format, output)

  quality = validate_quality!(quality)
  argv = [command, *IMAGEMAGICK_LIMIT_ARGS, input_arg, "-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_arg

  run_image_command(argv, output, ext, format, timeout, read: [input])
end

.run_image_command(argv, output, input_format, output_format, timeout, read: []) ⇒ Object 



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# File 'lib/safe_image/image_magick_backend.rb', line 339

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

  # Output dimensions via the helper's native header read, or identify when
  # the helper is unavailable (this backend must work without libvips).
  info = Native.available? ? Native.probe(output) : probe(output)
  {
    input_format: input_format == "generated" ? "generated" : Formats.normalize(input_format),
    output_format: Formats.normalize(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 50

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 



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# File 'lib/safe_image/image_magick_backend.rb', line 324

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

.validate_quality!(quality) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/safe_image/image_magick_backend.rb', line 317

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