Parent

MiniMagick::Image

Attributes

path[RW]

@return [String] The location of the current working file

Public Class Methods

create(ext = nil, validate = true, &block) click to toggle source

Used to create a new Image object data-copy. Not used to “paint” or that kind of thing.

Takes an extension in a block and can be used to build a new Image object. Used by both open and read to create a new object! Ensures we have a good tempfile!

@param ext [String] Specify the extension you want to read it as @param validate [Boolean] If false, skips validation of the created image. Defaults to true. @yield [IOStream] You can write bits to this object to create the new Image @return [Image] The created image

# File lib/mini_magick.rb, line 154
def create(ext = nil, validate = true, &block)
  begin
    tempfile = Tempfile.new(['mini_magick', ext.to_s.downcase])
    tempfile.binmode
    block.call(tempfile)
    tempfile.close

    image = self.new(tempfile.path, tempfile)

    if validate and !image.valid?
      raise MiniMagick::Invalid
    end
    return image
  ensure
    tempfile.close if tempfile
  end
end
from_blob(blob, ext = nil) click to toggle source

@deprecated Please use Image.read instead!

# File lib/mini_magick.rb, line 81
def from_blob(blob, ext = nil)
  warn "Warning: MiniMagick::Image.from_blob method is deprecated. Instead, please use Image.read"
  create(ext) { |f| f.write(blob) }
end
from_file(file, ext = nil) click to toggle source

@deprecated Please use MiniMagick::Image.open(file_or_url) now

# File lib/mini_magick.rb, line 140
def from_file(file, ext = nil)
  warn "Warning: MiniMagick::Image.from_file is now deprecated. Please use Image.open"
  open(file, ext)
end
import_pixels(blob, columns, rows, depth, map, format="png") click to toggle source

Creates an image object from a binary string blob which contains raw pixel data (i.e. no header data).

Returns

Parameters

  • blob

    String -- Binary string blob containing raw pixel data.

  • columns

    Integer -- Number of columns.

  • rows

    Integer -- Number of rows.

  • depth

    Integer -- Bit depth of the encoded pixel data.

  • map

    String -- A code for the mapping of the pixel data. Example: 'gray' or 'rgb'.

  • format

    String -- The file extension of the image format to be used when creating the image object. Defaults to 'png'.

# File lib/mini_magick.rb, line 101
def import_pixels(blob, columns, rows, depth, map, format="png")
  # Create an image object with the raw pixel data string:
  image = create(".dat", validate = false) { |f| f.write(blob) }
  # Use ImageMagick to convert the raw data file to an image file of the desired format:
  converted_image_path = image.path[0..-4] + format
  argument = "-size #{columns}x#{rows} -depth #{depth} #{map}:#{image.path} #{converted_image_path}"
  cmd = CommandBuilder.new("convert", argument) #Example: convert -size 256x256 -depth 16 gray:blob.dat blob.png
  image.run(cmd)
  # Update the image instance with the path of the properly formatted image, and return:
  image.path = converted_image_path
  image
end
new(input_path, tempfile = nil) click to toggle source

Create a new MiniMagick::Image object

DANGER: The file location passed in here is the *working copy*. That is, it gets modified. you can either copy it yourself or use the MiniMagick::Image.open(path) method which creates a temporary file for you and protects your original!

@param input_path [String] The location of an image file @todo Allow this to accept a block that can pass off to Image#combine_options

# File lib/mini_magick.rb, line 181
def initialize(input_path, tempfile = nil)
  @path = input_path
  @tempfile = tempfile # ensures that the tempfile will stick around until this image is garbage collected.
end
open(file_or_url, ext = nil) click to toggle source

Opens a specific image file either on the local file system or at a URI.

Use this if you don’t want to overwrite the image file.

Extension is either guessed from the path or you can specify it as a second parameter.

If you pass in what looks like a URL, we require ‘open-uri’ before opening it.

@param file_or_url [String] Either a local file path or a URL that open-uri can read @param ext [String] Specify the extension you want to read it as @return [Image] The loaded image

# File lib/mini_magick.rb, line 125
def open(file_or_url, ext = nil)
  file_or_url = file_or_url.to_s # Force it to be a String... hell or highwater
  if file_or_url.include?("://")
    require 'open-uri'
    ext ||= File.extname(URI.parse(file_or_url).path)
    self.read(Kernel::open(file_or_url), ext)
  else
    ext ||= File.extname(file_or_url)
    File.open(file_or_url, "rb") do |f|
      self.read(f, ext)
    end
  end
end
read(stream, ext = nil) click to toggle source

This is the primary loading method used by all of the other class methods.

Use this to pass in a stream object. Must respond to Object#read(size) or be a binary string object (BLOBBBB)

As a change from the old API, please try and use IOStream objects. They are much, much better and more efficient!

Probably easier to use the open method if you want to open a file or a URL.

@param stream [IOStream, String] Some kind of stream object that needs to be read or is a binary String blob! @param ext [String] A manual extension to use for reading the file. Not required, but if you are having issues, give this a try. @return [Image]

# File lib/mini_magick.rb, line 62
def read(stream, ext = nil)
  if stream.is_a?(String)
    stream = StringIO.new(stream)
  elsif stream.is_a?(File)
    if File.respond_to?(:binread)
      stream = StringIO.new File.binread(stream.path.to_s)
    else
      stream = StringIO.new File.open(stream.path.to_s,"rb") { |f| f.read }
    end
  end

  create(ext) do |f|
    while chunk = stream.read(8192)
      f.write(chunk)
    end
  end
end

Public Instance Methods

<<(*args) click to toggle source

Sends raw commands to imagemagick’s `mogrify` command. The image path is automatically appended to the command.

Remember, we are always acting on this instance of the Image when messing with this.

@return [String] Whatever the result from the command line is. May not be terribly useful.

# File lib/mini_magick.rb, line 255
def <<(*args)
  run_command("mogrify", *args << escaped_path)
end
[](value) click to toggle source

A rather low-level way to interact with the “identify” command. No nice API here, just the crazy stuff you find in ImageMagick. See the examples listed!

@example

image["format"]      #=> "TIFF"
image["height"]      #=> 41 (pixels)
image["width"]       #=> 50 (pixels)
image["colorspace"]  #=> "DirectClassRGB"
image["dimensions"]  #=> [50, 41]
image["size"]        #=> 2050 (bits)
image["original_at"] #=> 2005-02-23 23:17:24 +0000 (Read from Exif data)
image["EXIF:ExifVersion"] #=> "0220" (Can read anything from Exif)

@param format [String] A format for the “identify” command @see For reference see www.imagemagick.org/script/command-line-options.php#format @return [String, Numeric, Array, Time, Object] Depends on the method called! Defaults to String for unknown commands

# File lib/mini_magick.rb, line 220
def [](value)
  # Why do I go to the trouble of putting in newlines? Because otherwise animated gifs screw everything up
  case value.to_s
  when "colorspace"
    run_command("identify", "-quiet", "-format", format_option("%r"), escaped_path).split("\n")[0]
  when "format"
    run_command("identify", "-quiet", "-format", format_option("%m"), escaped_path).split("\n")[0]
  when "height"
    run_command("identify", "-quiet", "-format", format_option("%h"), escaped_path).split("\n")[0].to_i
  when "width"
    run_command("identify", "-quiet", "-format", format_option("%w"), escaped_path).split("\n")[0].to_i
  when "dimensions"
    run_command("identify", "-quiet", "-format", format_option("%w %h"), escaped_path).split("\n")[0].split.map{|v|v.to_i}
  when "size"
    File.size(@path) # Do this because calling identify -format "%b" on an animated gif fails!
  when "original_at"
    # Get the EXIF original capture as a Time object
    Time.local(*self["EXIF:DateTimeOriginal"].split(/:|\s+/)) rescue nil
  when /^EXIF\:/
    result = run_command('identify', '-quiet', '-format', "\"%[#{value}]\"", escaped_path).chop
    if result.include?(",")
      read_character_data(result)
    else
      result
    end
  else
    run_command('identify', '-quiet', '-format', "\"#{value}\"", escaped_path).split("\n")[0]
  end
end
collapse!() click to toggle source

Collapse images with sequences to the first frame (ie. animated gifs) and preserve quality

# File lib/mini_magick.rb, line 298
def collapse!
  run_command("mogrify", "-quality", "100", "#{path}[0]")
end
combine_options(tool = :mogrify, &block) click to toggle source

You can use multiple commands together using this method. Very easy to use!

@example

image.combine_options do |c|
  c.draw "image Over 0,0 10,10 '#{MINUS_IMAGE_PATH}'"
  c.thumbnail "300x500>"
  c.background background
end

@yieldparam command [CommandBuilder]

# File lib/mini_magick.rb, line 356
def combine_options(tool = :mogrify, &block)
  c = CommandBuilder.new(tool)

  c << @path if tool == :convert
  block.call(c)
  c << @path
  run(c)
end
composite(other_image, output_extension = 'jpg', &block) click to toggle source
# File lib/mini_magick.rb, line 370
def composite(other_image, output_extension = 'jpg', &block)
  begin
    second_tempfile = Tempfile.new(output_extension)
    second_tempfile.binmode
  ensure
    second_tempfile.close
  end

  command = CommandBuilder.new("composite")
  block.call(command) if block
  command.push(other_image.path)
  command.push(self.path)
  command.push(second_tempfile.path)

  run(command)
  return Image.new(second_tempfile.path, second_tempfile)
end
destroy!() click to toggle source
# File lib/mini_magick.rb, line 424
def destroy!
  return if @tempfile.nil?
  File.unlink(@tempfile.path) if File.exists?(@tempfile.path)
  @tempfile = nil
end
escaped_path() click to toggle source
# File lib/mini_magick.rb, line 186
def escaped_path
  Pathname.new(@path).to_s.inspect
end
format(format, page = 0) click to toggle source

This is used to change the format of the image. That is, from “tiff to jpg” or something like that. Once you run it, the instance is pointing to a new file with a new extension!

DANGER: This renames the file that the instance is pointing to. So, if you manually opened the file with Image.new(file_path)... then that file is DELETED! If you used Image.open(file) then you are ok. The original file will still be there. But, any changes to it might not be...

Formatting an animation into a non-animated type will result in ImageMagick creating multiple pages (starting with 0). You can choose which page you want to manipulate. We default to the first page.

@param format [String] The target format… like ‘jpg’, ‘gif’, ‘tiff’, etc. @param page [Integer] If this is an animated gif, say which ‘page’ you want with an integer. Leave as default if you don’t care. @return [nil]

# File lib/mini_magick.rb, line 273
def format(format, page = 0)
  c = CommandBuilder.new('mogrify', '-format', format)
  yield c if block_given?
  c << @path
  run(c)

  old_path = @path.dup
  @path.sub!(/(\.\w*)?$/, ".#{format}")
  File.delete(old_path) if old_path != @path

  unless File.exists?(@path)
    begin
      FileUtils.copy_file(@path.sub(".#{format}", "-#{page}.#{format}"), @path)
    rescue => ex
      raise MiniMagick::Error, "Unable to format to #{format}; #{ex}" unless File.exist?(@path)
    end
  end
ensure
  Dir[@path.sub(/(\.\w+)?$/, "-[0-9]*.#{format}")].each do |fname|
    File.unlink(fname)
  end
end
format_option(format) click to toggle source

Outputs a carriage-return delimited format string for Unix and Windows

# File lib/mini_magick.rb, line 389
def format_option(format)
  windows? ? "\"#{format}\\n\"" : "\"#{format}\\\\n\""
end
method_missing(symbol, *args) click to toggle source

If an unknown method is called then it is sent through the mogrify program Look here to find all the commands (www.imagemagick.org/script/mogrify.php)

# File lib/mini_magick.rb, line 340
def method_missing(symbol, *args)
  combine_options do |c|
    c.method_missing(symbol, *args)
  end
end
mime_type() click to toggle source
# File lib/mini_magick.rb, line 333
def mime_type
  format = self[:format]
  "image/" + format.to_s.downcase
end
run(command_builder) click to toggle source
# File lib/mini_magick.rb, line 402
def run(command_builder)
  command = command_builder.command

  sub = Subexec.run(command, :timeout => MiniMagick.timeout)

  if sub.exitstatus != 0
    # Clean up after ourselves in case of an error
    destroy!

    # Raise the appropriate error
    if sub.output =~ /no decode delegate/ || sub.output =~ /did not return an image/
      raise Invalid, sub.output
    else
      # TODO: should we do something different if the command times out ...?
      # its definitely better for logging.. otherwise we dont really know
      raise Error, "Command (#{command.inspect.gsub("\\", "")}) failed: #{{:status_code => sub.exitstatus, :output => sub.output}.inspect}"
    end
  else
    sub.output
  end
end
run_command(command, *args) click to toggle source
# File lib/mini_magick.rb, line 393
def run_command(command, *args)
  # -ping "efficiently determine image characteristics."
  if command == 'identify'
    args.unshift '-ping'
  end

  run(CommandBuilder.new(command, *args))
end
to_blob() click to toggle source

Gives you raw image data back @return [String] binary string

# File lib/mini_magick.rb, line 325
def to_blob
  f = File.new @path
  f.binmode
  f.read
ensure
  f.close if f
end
valid?() click to toggle source

Checks to make sure that MiniMagick can read the file and understand it.

This uses the ‘identify’ command line utility to check the file. If you are having issues with this, then please work directly with the ‘identify’ command and see if you can figure out what the issue is.

@return [Boolean]

# File lib/mini_magick.rb, line 197
def valid?
  run_command("identify", @path)
  true
rescue MiniMagick::Invalid
  false
end
windows?() click to toggle source

Check to see if we are running on win32 – we need to escape things differently

# File lib/mini_magick.rb, line 366
def windows?
  RUBY_PLATFORM =~ /mswin|mingw|cygwin/
end
write(output_to) click to toggle source

Writes the temporary file out to either a file location (by passing in a String) or by passing in a Stream that you can write(chunk) to repeatedly

@param output_to [IOStream, String] Some kind of stream object that needs to be read or a file path as a String @return [IOStream, Boolean] If you pass in a file location [String] then you get a success boolean. If its a stream, you get it back. Writes the temporary image that we are using for processing to the output path

# File lib/mini_magick.rb, line 308
def write(output_to)
  if output_to.kind_of?(String) || !output_to.respond_to?(:write)
    FileUtils.copy_file @path, output_to
    run_command "identify", output_to.to_s.inspect # Verify that we have a good image
  else # stream
    File.open(@path, "rb") do |f|
      f.binmode
      while chunk = f.read(8192)
        output_to.write(chunk)
      end
    end
    output_to
  end
end

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