provide access to image media types, resolves #22

CHANGELOG.markdown

@@ -2,6 +2,7 @@
 
 ## unreleased
 
+* Provide access to media types using media_type and media_types methods [#22](https://github.com/toy/image_size/issues/22) [@toy](https://github.com/toy)
 * Allow fetching from HTTP server by requiring image_size/uri [@toy](https://github.com/toy)
 * Fix for ArgumentError when requiring only image_size/uri_reader (without image_size) [@toy](https://github.com/toy)
 * Require ruby 1.9.3 [@toy](https://github.com/toy)

README.markdown

@@ -26,7 +26,7 @@ gem 'image_size', '~> 3.0'
 ```ruby
 image_size = ImageSize.path('spec/images/jpeg/436x429.jpeg')
 
-image_size.format       #=> :jpec
+image_size.format       #=> :jpeg
 image_size.width        #=> 436
 image_size.height       #=> 429
 image_size.w            #=> 436
@@ -38,6 +38,8 @@ image_size.size.width   #=> 436
 image_size.size.height  #=> 429
 image_size.size.w       #=> 436
 image_size.size.h       #=> 429
+image_size.media_type   #=> "image/jpeg"
+image_size.media_types  #=> ["image/jpeg"]
 ```
 
 Or using `IO` object:

lib/image_size.rb

@@ -3,6 +3,7 @@
 
 require 'image_size/isobmff'
 require 'image_size/format_error'
+require 'image_size/media_types'
 require 'image_size/reader'
 require 'image_size/seekable_io_reader'
 require 'image_size/stream_io_reader'
@@ -69,6 +70,19 @@ def size
     Size.new([width, height]) if format
   end
 
+  # Media type (formerly known as a MIME type)
+  def media_type
+    MEDIA_TYPES.fetch(format, []).first
+  end
+
+  # 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
+  def media_types
+    MEDIA_TYPES.fetch(format, [])
+  end
+
 private
 
   SVG_R = /<svg\b([^>]*)>/.freeze

lib/image_size/media_types.rb

@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+class ImageSize
+  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],
+    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
+end

spec/image_size_spec.rb

@@ -68,13 +68,17 @@ def supported_formats
           format = match[3].to_sym
         end
         size = format && [width, height]
+        media_types = ImageSize::MEDIA_TYPES[format] || []
+        media_type = format && media_types.first.to_s
         {
           format: format,
           width: width,
           height: height,
           w: width,
           h: height,
           size: size,
+          media_type: media_type,
+          media_types: media_types,
         }
       end
       let(:file_data){ File.binread(path) }