-- File:	Image_AveragePixelInterpolation.cdl
-- Created:	Tue Jul 27 18:47:06 1993
-- Author:	Jean Louis FRENKEL
--		<jlf@sparc3>
---Copyright:	 Matra Datavision 1993


class AveragePixelInterpolation from Image inherits PixelInterpolation from Image

	---Purpose: The class AveragePixelInterpolation is used to compute a SubPixel 
	--            value on non integer Image coordinate
	--          AveragePixelInterpolation redefined a new method to compute a
	--	      SubPixel value .
	--	    SubPixel value is the average of the three nearest Pixel in 
	--	      the Image .
	--	    If V1, V2, V3, V4 is the value of the three nearest Image 
	--	      Pixel V = ( V1+V2+V3 ) / 3 is the Image SubPixel value
	--	      on non integer coordinate (FX,FY)


uses

    Image 		from Image,
    Pixel       	from Aspect,
    ColorPixel       	from Aspect,
    IndexPixel       	from Aspect,
    DColorImage 	from Image,
    DIndexedImage 	from Image

is

    	Create returns AveragePixelInterpolation from Image ;
	---Level: Public
    	---Purpose: Create a AveragePixelInterpolation  object.

	Interpolate( me ; aImage   : Image from Image ;
		          FX,FY      : Real  from Standard ;
			  LowerX,LowerY,UpperX,UpperY : Integer from Standard ;
		          RetPixel : in out Pixel from Aspect ) 
		returns Boolean from Standard is redefined ;
	---Level: Public
    	---Purpose: Redefined the method to compute SubPixel's value 
	--	      on non integer Image coordinate.
	--	    LowerX,LowerY,UpperX,UpperY is the Image Min Max, it's use
	--	    check if the SubPixel coordinate FX,FY is outside of image.
	--          Return True  if Interpolation Succes.
	--	    Return False if the SubPixel is out from Image.

	Interpolate( me ; aImage   : DColorImage from Image ;
		          FX,FY      : Real  from Standard ;
			  LowerX,LowerY,UpperX,UpperY : Integer from Standard ;
		          RetPixel : in out ColorPixel from Aspect ) 
		returns Boolean from Standard  is redefined;
	---Level: Public
    	---Purpose: Compute SubPixel's value on non integer Image coordinate for
	--	      DColorImage and ColorPixel.
	--	    LowerX,LowerY,UpperX,UpperY is the Image Min Max, it's use
	--	    check if the SubPixel coordinate FX,FY is outside of image.
	--          Return True  if Interpolation Succes.
	--	    Return False if the SubPixel is out from Image.


	Interpolate( me ; aImage   : DIndexedImage from Image ;
		          FX,FY      : Real  from Standard ;
			  LowerX,LowerY,UpperX,UpperY : Integer from Standard ;
		          RetPixel : in out IndexPixel from Aspect ) 
		returns Boolean from Standard  is redefined;
	---Level: Public
    	---Purpose: Compute SubPixel's value on non integer Image coordinate for
	--	      DIndexedImage and IndexPixel.
	--	    LowerX,LowerY,UpperX,UpperY is the Image Min Max, it's use
	--	    check if the SubPixel coordinate X,Y is outside of image.
	--          Return True  if Interpolation Succes.
	--	    Return False if the SubPixel is out from Image.

end AveragePixelInterpolation from Image;