NL::FastPng

NL::FastPng is a C-based extension that uses libpng in a simplified configuration for faster performance on grayscale images, at the expense of slightly larger file sizes.

This code was used by the Nitrogen Logic Depth Camera Controller to generate PNG images from realtime depth data on limited hardware.

NL::FastPng is licensed under a 2-clause BSD license. See the LICENSE file for details. NL::FastPng is © 2011-2020, Mike Bourgeous.

Add this line to your application's Gemfile:

gem 'nl-fast_png', git: 'git@github.com:nitrogenlogic/nl-fast_png.git'

And then execute:

$ bundle install

require 'nl/fast_png'

# Store a 2x2 checkerboard pattern to /tmp/x.png
File.write('/tmp/x.png', NL::FastPng.store_png(2, 2, 8, "\xff\x00\x00\xff"))

# Store a 256x256 horizontal gradient to /tmp/grad.png
File.write('/tmp/grad.png', NL::FastPng.store_png(256, 256, 8, 256.times.map(&:chr).join * 256))