cast.cr

require "gobject"
require_gobject "Vips"

class Vips::Image
  def self.new_from_file(path : String)
    Vips::Image.new_from_file_rw(path)
  end

  # https://www.rubydoc.info/gems/ruby-vips/Vips/Image#cast-instance_method
  def vips_cast(format)
    LibVips.vips_cast(self, out casted, format)
    Vips::Image.new(casted)
  end
end

lib LibVips
  alias Img = LibVips::Image
  # https://libvips.github.io/libvips/API/current/libvips-conversion.html#vips-cast
  fun vips_cast(input : Img*, output : Img**, band : Int32)
end

puts "Reading image"
img = Vips::Image.new_from_file("/home/frog/dhash-cr/test.jpg")
puts "Read img with width #{img.width} and height #{img.height}"

img.vips_cast(Vips::BandFormat::INT)