A fast and convenient image processing library

Documentation

• Main
• Stable

Currently supported

• Image formats
  • JPEG (through libjpeg-turbo)
  • PNG (through libspng)
  • PPM
  • StumpyCore
  • WebP (through libwebp)
    • WebP 1.3+ linking flags are used by default. If you have an older version installed, compile with the -Dlegacy_webp flag to skip the requirement for libsharpyuv.
• Image operations
  • Bilinear resize
  • Box blur
  • Brightness
  • Channel swap
  • Contrast
  • Crop
  • Gaussian blur
  • Horizontal blur
  • Padding
  • Rotation
  • Vertical blur

Installation

1. Add the dependency to your shard.yml:

   dependencies:
     pluto:
       github: phenopolis/pluto

2. Run shards install.

Usage

Basic

require "pluto"

# Formats requiring linkinkg a C library must be explicitly `require`d
require "pluto/format/jpeg"
require "pluto/format/png"
require "pluto/format/webp"

image = File.open("lib/pluto_samples/desert.png") do |file|
  Pluto::ImageRGBA.from_png(file)
end

image.contrast(-100)  # Creates a new object
image.contrast!(-100) # Modifies the existing object

io = IO::Memory.new
image.to_jpeg(io)
io.rewind
File.write("output.jpeg", io)

StumpyCore

Pluto can convert to and from StumpyCore Canvas objects, so any format that Stumpy supports can be usable with Pluto as well.

require "pluto"
require "stumpy_png"

canvas = StumpyPNG.read("lib/pluto_samples/desert.png") # => StumpyCore::Canvas
image = Pluto::ImageRGBA.from_stumpy(canvas)            # => Pluto::ImageRGBA
image.to_stumpy                                         # => StumpyCore::Canvas

Note

Converting from a StumpyCore::Canvas created from a 16-bit image will result in a loss of information, since Pluto currently only supports 8 bit.

More

See the API or the spec/ folder for more examples.

Benchmarks

See BENCHMARKS.md.

Contributing

1. Fork it (https://github.com/phenopolis/pluto/fork).
2. Create your feature branch (git checkout -b my-new-feature).
3. Commit your changes (git commit -am 'Add some feature').
4. Push to the branch (git push origin my-new-feature).
5. Create a new Pull Request.