Class: ImageSize

Inherits:
Object
  • Object
show all
Defined in:
lib/image_size.rb,
lib/image_size/reader.rb,
lib/image_size/isobmff.rb,
lib/image_size/uri_reader.rb,
lib/image_size/media_types.rb,
lib/image_size/format_error.rb,
lib/image_size/chunky_reader.rb,
lib/image_size/string_reader.rb,
lib/image_size/stream_io_reader.rb,
lib/image_size/seekable_io_reader.rb

Overview

Experimental, not yet part of stable API

It adds ability to fetch image meta from HTTP server while downloading only needed chunks if the server recognises Range header, otherwise fetches only required amount of data

Defined Under Namespace

Modules: ChunkyReader, Reader, URIReader Classes: FormatError, ISOBMFF, SeekableIOReader, Size, StreamIOReader, StringReader

Constant Summary collapse

MEDIA_TYPES = 
{
  apng: %w[image/apng image/vnd.mozilla.apng],
  avif: %w[image/avif],
  bmp: %w[image/bmp],
  cur: %w[image/vnd.microsoft.icon],
  emf: %w[image/emf],
  gif: %w[image/gif],
  heic: %w[image/heic image/heif],
  icns: %w[image/x-icns],
  ico: %w[image/x-icon image/vnd.microsoft.icon],
  j2c: %w[image/j2c],
  jp2: %w[image/jp2],
  jpeg: %w[image/jpeg],
  jpx: %w[image/jpx],
  mng: %w[video/x-mng image/x-mng],
  pam: %w[image/x-portable-arbitrarymap],
  pbm: %w[image/x-portable-bitmap image/x-portable-anymap],
  pcx: %w[image/x-pcx image/vnd.zbrush.pcx],
  pgm: %w[image/x-portable-graymap image/x-portable-anymap],
  png: %w[image/png],
  ppm: %w[image/x-portable-pixmap image/x-portable-anymap],
  psd: %w[image/vnd.adobe.photoshop],
  svg: %w[image/svg+xml],
  swf: %w[application/x-shockwave-flash application/vnd.adobe.flash.movie],
  tiff: %w[image/tiff],
  webp: %w[image/webp],
  xbm: %w[image/x-xbitmap],
  xpm: %w[image/x-xpixmap],
}.freeze

Class Attribute Summary collapse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data) ⇒ ImageSize

Given image as any class responding to read and eof? or data as String, finds its format and dimensions



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# File 'lib/image_size.rb', line 71

def initialize(data)
  Reader.open(data) do |ir|
    @format = detect_format(ir)
    @width, @height = send("size_of_#{@format}", ir) if @format
    @byte_size = ir.byte_size
  end
end

Class Attribute Details

.use_display_pixels ⇒ Object

Use display pixels instead of physical/image pixels for icns



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# File 'lib/image_size.rb', line 53

def use_display_pixels
  @use_display_pixels
end

Instance Attribute Details

#byte_size ⇒ Object (readonly)

Returns the value of attribute byte_size.



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# File 'lib/image_size.rb', line 90

def byte_size
  @byte_size
end

#format ⇒ Object (readonly)

Image format



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# File 'lib/image_size.rb', line 80

def format
  @format
end

#height ⇒ Object (readonly) Also known as: h

Image height



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# File 'lib/image_size.rb', line 87

def height
  @height
end

#width ⇒ Object (readonly) Also known as: w

Image width



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# File 'lib/image_size.rb', line 83

def width
  @width
end

Class Method Details

.chunk_size ⇒ Object

Size of chunk to use by IO and URI readers



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# File 'lib/image_size.rb', line 56

def chunk_size
  @chunk_size || 4096
end

.chunk_size=(chunk_size) ⇒ Object

Set size of chunk to use by IO and URI readers



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# File 'lib/image_size.rb', line 61

def chunk_size=(chunk_size)
  unless chunk_size.nil? || (chunk_size.is_a?(Integer) && chunk_size > 0)
    fail ArgumentError, "chunk_size should be a positive Integer or nil, got #{chunk_size}"
  end

  @chunk_size = chunk_size
end

.dpi ⇒ Object

DPI used for svg and emf



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# File 'lib/image_size.rb', line 41

def dpi
  @dpi || 72.0
end

.dpi=(dpi) ⇒ Object

Set DPI used for svg and emf



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# File 'lib/image_size.rb', line 46

def dpi=(dpi)
  fail ArgumentError, "dpi should be nil or positive, got #{dpi}" unless dpi.nil? || dpi > 0

  @dpi = dpi ? dpi.to_f : nil
end

.max_redirects ⇒ Object

Maximum number of redirects



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# File 'lib/image_size/uri_reader.rb', line 152

def self.max_redirects
  @max_redirects || 5
end

.max_redirects=(max_redirects) ⇒ Object

Set maximum number of redirects



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# File 'lib/image_size/uri_reader.rb', line 157

def self.max_redirects=(max_redirects)
  unless max_redirects.nil? || (max_redirects.is_a?(Integer) && max_redirects >= 0)
    fail ArgumentError, "max_redirects should be 0, a positive Integer or nil, got #{max_redirects}"
  end

  @max_redirects = max_redirects
end

.path(path) ⇒ Object

Given path to image finds its format, width and height



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# File 'lib/image_size.rb', line 36

def path(path)
  new(Pathname.new(path))
end

.uri_checker ⇒ Object

Hook to call before making every request



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# File 'lib/image_size/uri_reader.rb', line 166

def self.uri_checker
  @uri_checker || proc{ |_uri| }
end

.uri_checker=(uri_checker) ⇒ Object

Set hook to call before making every request



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# File 'lib/image_size/uri_reader.rb', line 171

def self.uri_checker=(uri_checker)
  unless uri_checker.nil? || uri_checker.respond_to?(:call)
    fail ArgumentError, "uri_checker should respond to call or be nil, got #{uri_checker}"
  end

  @uri_checker = uri_checker
end

.url(url) ⇒ Object 



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# File 'lib/image_size/uri_reader.rb', line 147

def self.url(url)
  new(url.is_a?(URI) ? url : URI(url))
end

Instance Method Details

#media_type ⇒ Object

Media type (formerly known as a MIME type)



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# File 'lib/image_size.rb', line 98

def media_type
  media_types.first
end

#media_types ⇒ Object

All media types:

  • commonly used and official like for apng and ico

  • main and compatible like for heic and pnm (pbm, pgm, ppm)

  • multiple unregistered like for mng



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# File 'lib/image_size.rb', line 106

def media_types
  MEDIA_TYPES.fetch(format, [])
end

#size ⇒ Object

get image width and height as an array which to_s method returns “##widthx##height”



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# File 'lib/image_size.rb', line 93

def size
  Size.new([width, height]) if format
end