Redaction

• Example
• Processor Support

Redactions are black rectangles that are overlaid onto source images in order to obscure parts of them. This can be used for copyright protection, privacy protection, or censorship, without altering any source images. Different redactions can be applied to the same image dynamically for different audiences based on client IP address, cookies, and more.

Redactions are defined with x, y, width, and height properties corresponding to source image coordinates. Redacted regions are blacked out at every intersecting crop region and scale.

The redaction feature works via the delegate system. The delegate must implement a method called redactions() that returns an array of source image redaction coordinates in response to a particular request.

Example

class CustomDelegate
  def redactions(options = {})
    redactions = []
    # Add two redactions to an image with an identifier of "sample" for all
    # clients except localhost.
    if context['identifier'] == 'sample'
      unless %w(127.0.0.1 ::1/128).include?(context['client_ip'])
        redactions << {
            'x' => 50,
            'y' => 65,
            'width' => 120,
            'height' => 105
        }
        redactions << {
            'x' => 673,
            'y' => 812,
            'width' => 1320,
            'height' => 620
        }
      end
    end
    redactions
  end
end

Processor Support

Not all processors support redaction; see the table of processor-supported features.