Useful image filters (Instagram/Hipster/Cool) for CarrierWave using MiniMagick (ImageMagick)

image_filters.rb

module CarrierWave
  module MiniMagick
    def toaster_filter
      manipulate! do |img|
        img.modulate '150,80,100'
        img.gamma 1.1
        img.contrast
        img.contrast
        img.contrast
        img.contrast

        img = yield(img) if block_given?
        img
      end
    end

    def lomo_filter
      manipulate! do |img|
        img.channel 'R'
        img.level '22%'
        img.channel 'G'
        img.level '22%'

        img = yield(img) if block_given?
        img
      end
    end

    def kelvin_filter
      manipulate! do |img|
        cols, rows = img[:dimensions]

        img.combine_options do |cmd|
          cmd.auto_gamma
          cmd.modulate '120,50,100'
        end

        new_img = img.clone
        new_img.combine_options do |cmd|
          cmd.fill 'rgba(255,153,0,0.5)'
          cmd.draw "rectangle 0,0 #{cols},#{rows}"
        end

        img = img.composite new_img do |cmd|
          cmd.compose 'multiply'
        end

        img = yield(img) if block_given?
        img
      end
    end

    def colortone_filter(color = '#222b6d', level = 100, type = 0)
      manipulate! do |img|
        color_img = img.clone
        color_img.combine_options do |cmd|
          cmd.fill color
          cmd.colorize '63%'
        end

        img = img.composite color_img do |cmd|
          cmd.compose 'blend'
          cmd.define "compose:args=#{level},#{100-level}"
        end

        img = yield(img) if block_given?
        img
      end
    end

    def gotham_filter
      manipulate! do |img|
        img.modulate '120,10,100'
        img.fill '#222b6d'
        img.colorize 20
        img.gamma 0.5
        img.contrast

        img = yield(img) if block_given?
        img
      end
    end

    def strip
      manipulate! do |img|
        img.strip

        img = yield(img) if block_given?
        img
      end
    end

    def quality(percentage)
      manipulate! do |img|
        img.quality(percentage)

        img = yield(img) if block_given?
        img
      end
    end

    def vignette(path_to_file)
      manipulate! do |img|
        cols, rows = img[:dimensions]

        vignette_img = ::MiniMagick::Image.open(path_to_file)
        vignette_img.size "#{cols}x#{rows}"

        img = img.composite(vignette_img) do |cmd|
          cmd.gravity 'center'
          cmd.compose 'multiply'
        end

        img = yield(img) if block_given?
        img
      end
    end

    def pad_it_up(width, height, background=:transparent, gravity='Center')
      manipulate! do |img|
        cols, rows = img[:dimensions]

        if width > cols || height > rows
          img.combine_options do |cmd|
            if background == :transparent
              cmd.background "rgba(255, 255, 255, 0.0)"
            else
              cmd.background background
            end
            cmd.gravity gravity
            if width > cols && height > rows
              cmd.extent "#{width}x#{height}"
            elsif width > cols
              cmd.extent "#{width}x#{rows}"
            else
              cmd.extent "#{cols}x#{height}"
            end
          end
        end

        img = yield(img) if block_given?
        img
      end
    end
  end
end