Macruby Face Detection in Mac OS X Lion. Usage: $ macruby face_detector.rb or $ macruby face_detector.rb image_url

face_detector.rb

framework 'Cocoa'

class NSColor 
  def toCGColor
    color_RGB = colorUsingColorSpaceName(NSCalibratedRGBColorSpace)
    ## approach #1
    # components = Array.new(4){Pointer.new(:double)}
    # color_RGB.getRed(components[0],
    #                 green: components[1],
    #                 blue: components[2],
    #                 alpha:components[3])
    # components.collect!{|x| x[0] }
    # approach #2
    components = [redComponent, greenComponent, blueComponent, alphaComponent]
    
    color_space = CGColorSpaceCreateWithName(KCGColorSpaceGenericRGB)
    color = CGColorCreate(color_space, components)
    CGColorSpaceRelease(color_space)
    color
  end
end

# NSVIew set background color & and set center
class NSView

  # set background like on IOS
  def background_color=(color)
    viewLayer = CALayer.layer
    viewLayer.backgroundColor = color.toCGColor
    self.wantsLayer = true # // view's backing store is using a Core Animation Layer
    self.layer = viewLayer
  end

  # helper to set nsview center like on IOS
  def center= (point)
    self.frameOrigin = [point.x-(self.frame.size.width/2), point.y-(self.frame.size.height/2)]
    self.needsDisplay = true
  end
end

# NSImage to CGImage
class NSImage 
  def to_CGImage
    source = CGImageSourceCreateWithData(self.TIFFRepresentation, nil)
    maskRef = CGImageSourceCreateImageAtIndex(source, 0, nil)
  end
end

class FaceDetectionDelegate
  attr_accessor :window

  def initWithURL(url)
    case url
    when String
       @photo_url = NSURL.URLWithString(url)
    when NSURL
      @photo_url = url
    else
      raise "The FaceDetectionDelegate class was initiated with an unknown type object"
    end
    self
  end
  
  def applicationDidFinishLaunching(aNotification)
    window.delegate = self
    puts "Fetching and loading the image #{@photo_url.absoluteString}"
    image = NSImage.alloc.initWithContentsOfURL @photo_url
    
    # Helpers to set the NSImageView size
    bitmap = NSBitmapImageRep.imageRepWithData image.TIFFRepresentation
    puts "image size: w=#{bitmap.pixelsWide}, h=#{bitmap.pixelsHigh}" if bitmap
    
    imageView = NSImageView.alloc.init
    imageView.image = image
    imageView.wantsLayer = true
    imageView.imageScaling = NSImageScaleProportionallyUpOrDown
    imageView.layer.affineTransform = CGAffineTransformMakeScale(-1, 1)
    imageView.imageFrameStyle = NSImageFramePhoto
    
    window.setFrame([0.0, 0.0, (bitmap.pixelsWide+20), (bitmap.pixelsHigh+20)], display:true, animate:true)
    window.center
    
    window.contentView.wantsLayer = true
    window.contentView.layer.affineTransform = CGAffineTransformMakeScale(1, 1)
    
    imageView.frame = CGRectMake(0.0, 0.0, bitmap.pixelsWide, bitmap.pixelsHigh)
    window.contentView.addSubview(imageView)
    detect_faces
    window.orderFrontRegardless
  end
  
  def detect_faces
    ciImage = CIImage.imageWithCGImage window.contentView.subviews.last.image.to_CGImage
    mustacheImage = NSImage.alloc.initWithContentsOfFile "mustache_03.png"

    detectorOptions = {CIDetectorAccuracy: CIDetectorAccuracyHigh }
    detector = CIDetector.detectorOfType "CIDetectorTypeFace", context:nil, options:detectorOptions

    features = detector.featuresInImage(ciImage)
    features.each do |feature|
      if(feature.hasMouthPosition)
        imageView = NSImageView.alloc.init
        imageView.image = mustacheImage
        imageView.wantsLayer = true
        imageView.imageScaling = NSImageScaleProportionallyUpOrDown
        imageView.layer.affineTransform = CGAffineTransformMakeScale(-1, 1)
        imageView.imageFrameStyle = NSImageFrameNone
        imageView.frame = CGRectMake(0.0, 0.0, 40, 15)
        imageView.center = feature.mouthPosition
        window.contentView.addSubview(imageView)
      end
    end
  end

  def windowWillClose(sender); exit(1); end

end

# Create the Application
application = NSApplication.sharedApplication
NSApplication.sharedApplication.activationPolicy = NSApplicationActivationPolicyRegular
application.delegate = FaceDetectionDelegate.alloc.initWithURL(ARGV.shift || "http://merbist.com/wp-content/uploads/2010/03/matz_koichi_matt_aimonetti_sansonetti_jimmy.jpg")

# create the Application Window
frame = [0.0, 0.0, 330, 250]
window = NSWindow.alloc.initWithContentRect frame, 
                                  styleMask: NSTitledWindowMask | NSClosableWindowMask,
                                    backing: NSBackingStoreBuffered,
                                      defer: false

application.delegate.window = window
window.orderOut(nil)
window.display
puts "Starting the app..."
application.run

mustache_03.png