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

The vignette needs to be a PNG transparent overlay.

Hi, just discovered this. Do you perhaps have an example of the overlay for the vignette filter, and what are some sample values for width and height in the pad_it_up filter (just so I can see some effect)?

Here's a sample vignette...

https://dl.dropboxusercontent.com/u/27290468/github/vignette.png

You can use any integer for the width/height for the pad_it_up filter. Basically, if your image is less than the dimensions you pass in, it will pad the image up to the those dimensions.

Thanks for this! I've tried using this and a similar vignette mask, but it doesn't seem to have any effect whatsoever. Did something perhaps change in the underlying code?

Also can't get the pad_it_up filter to work...my image is 500px X 500px, so I pass 1000 in for both width and height, to no effect.

The rest of them work beautifully though.