PalletePNG

PalletePNG is a pure-ruby library that make it possible to render the transparent of a pallete-based PNG in PDF by converting the color-mode of the image.

Installation

Add this line to your application's Gemfile:

gem 'pallete_png'

And then execute:

$ bundle

Or install it yourself as:

$ gem install pallete_png

Usage

require 'pallete_png'

image = File.binread('/path/to/pallete-based-w-transparency.png')
converted_image = PalletePNG.to_transparency(image)

Exception

require 'pallete_png'

not_a_png_image = File.binread('/path/to/not_a_png.jpg')

begin
  converted_image = PalletePNG.to_transparency(not_a_png_image)
rescue PalletePNG::Image::NotPNG
  puts 'The image is not a PNG.'
end

Use with Prawn

See Example::Using in Prawn.

Supported versions

Ruby 2.2, 2.3

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/hidakatsuya/pallete_png.