tulinmola/imagineer

Image processing in Elixir

Imagineer

Image parsing in Elixir. No external dependencies.

Status

Until 1.0 is reached, each beta release might include backwards incompatible changes. 1.0 will include parsing and writing of PNGs and JPEGs.

Currently Imagineer only supports reading and writing a subset of PNGs.

If you run into an image that Imagineer cannot handle, please open an issue and include the image. There are a ridiculous number of possiblities, not all of which are yet supported. With your help, we can get there.

Loading an image

To load an image, call Imagineer.load(path_to_file).

alias Imagineer.Image
Imagineer.load("./test/support/images/alpaca.png")
# =>
{:ok,
 %Imagineer.Image.PNG{alias: nil,
  attributes: %{"XML:com.adobe.xmp": "<x:xmpmeta xmlns:x=\"adobe:ns:meta/\" x:xmptk=\"XMP Core 5.4.0\">\n   <rdf:RDF xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\">\n      <rdf:Description rdf:about=\"\"\n            xmlns:exif=\"http://ns.adobe.com/exif/1.0/\">\n         <exif:PixelXDimension>96</exif:PixelXDimension>\n         <exif:PixelYDimension>96</exif:PixelYDimension>\n      </rdf:Description>\n   </rdf:RDF>\n</x:xmpmeta>\n",
    pixel_dimensions: {5669, 5669, :meter}}, bit_depth: 8, color_format: :rgb,
   color_type: 2, comment: nil, compression: :zlib,
   data_content: <<120, 1, 141, 189, 7, 148, 92, 213, 149, 254, 123, 99, 229, 208, 213, 57, 75, 106, 229, 0,
     66, 66, 18, 32, 178, 49, 57, 216, 132, 193, 9, 99, 96, 108, 6, 131, 3, 14, 51, 255, 97, ...>>,
   decompressed_data: nil, filter_method: :five_basics, format: :png, gamma: nil,
   height: 96, interface_method: 0, mask: nil, palette: [],
   pixels: [{238, 233, 224}, {241, 236, 227}, {238, 234, 225}, {238, 233, 225},
    {234, 228, 218}, {228, 222, 210}, {237, 231, 218}, {239, 234, 220}, ...], # 96 rows of 96 3-element tuples each omitted for sanity.
   raw: <<137, 80, 78, 71, 13, 10, 26, 10, 0, 0, 0, 13, 73, 72, 68, 82, 0, 0, 0, 96, 0, 0, 0, 96, 8, 2, 0, 0, #0, 109, 250, ...>>,
   scanlines: [], unfiltered_rows: [], uri: nil, width: 96}}

Writing an image

To write an image to disk, simply pass an image and a location to Imagineer.write.

{:ok, png} = Imagineer.load("./test/support/images/alpaca.png")
:ok = Imagineer.write(png, "./tmp/alpaca-copy.png")

Image modules also respond to to_binary, which will give you the equivalent of the file contents:

{:ok, png} = Imagineer.load("./test/support/images/alpaca.png")
Imagineer.Image.PNG.to_binary(png)

Image structure

You probably only care about the following fields:

• width
• height
• pixels
• color_format
• format
• palette
• gamma
• bit_depth

The color_format tells you how pixels are structured. :rgb indicates that each pixel will be a three value tuple (red, blue, and green channels.)

The bit_depth signifies the size of each channel. For example, a bit_depth of 8 says that each channel is 8 bits, translating to values between 0-255.