include resources "Flowersfb.jpg"

_window = 1
begin enum output 1
  _imageviewColor
  _imageviewGray
end enum

void local fn BuildWindow
  CGRect r = fn CGRectMake( 0, 0, 580, 300 )
  window _window, @"Color to Grayscale", r

  r = fn CGRectMake( 20, 20, 260, 260 )
  imageview _imageviewColor, YES, @"Flowersfb.jpg", r, NSImageScaleAxesIndependently, NSImageAlignCenter, NSImageFramePhoto

  r = fn CGRectMake( 300, 20, 260, 260 )
  imageview _imageviewGray, YES, @"Flowersfb.jpg", r, NSImageScaleAxesIndependently, NSImageAlignCenter, NSImageFramePhoto
end fn

local fn GrayscaleImage( image as ImageRef ) as ImageRef
  CGSize           size = fn ImageSize( image )
  CGRect         bounds = fn CGRectMake( 0, 0, size.width, size.height )
  ImageRef   finalImage = fn ImageWithSize( size )
  CFDataRef         dta = fn ImageTIFFRepresentationUsingCompression( image, NSTIFFCompressionNone, 0.0 )
  CIImageRef inputImage = fn CIImageWithData( dta )

  ImageLockFocus( finalImage )
  CIFilterRef filter = fn CIFilterWithNameAndInputParameters( @"CIPhotoEffectMono", @{kCIInputImageKey:inputImage} )
  CIImageRef outputCIImage = fn CIFilterOutputImage( filter )
  CIImageDrawAtPoint( outputCIImage, CGPointZero, bounds, NSCompositeCopy, 1.0 )
  ImageUnlockFocus( finalImage )
end fn = finalImage

fn BuildWindow

ImageRef colorFlowers
ImageRef  grayflowers

colorFlowers = fn ImageNamed( @"Flowersfb.jpg" )
grayflowers = fn GrayscaleImage( colorFlowers )
ImageViewSetImage( _imageviewGray, grayFlowers )

HandleEvents