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|#

;;;; 6.001 Images

(declare (usual-integrations))

;;; Procedure to build an image given a picture and the magnification factors

(define (build-image pic window h-sf v-sf pic-min pic-max)
  (let* ((gray-map (n-gray-map window))
	 (pic-height (picture-height pic))	;py
	 (pic-width (picture-width pic))	;x
	 (pic-data (picture-data pic))
	 (image-width (fix:* h-sf pic-width)) ;x
	 (image-height (fix:* v-sf pic-height)) ;iy
	 (use-string?
	  (every (lambda (n)
		   (<= 0 n 255))
		 (vector->list gray-map)))
	 (image (image/create window image-width image-height))
	 (pixels
	  (if use-string?
	      (make-legacy-string (fix:* image-width image-height))
	      (make-vector (fix:* image-width image-height))))
	 (write-pixel (if use-string? vector-8b-set! vector-set!))
	 (py-max (- pic-height 1))
	 (rect-index-height (fix:* v-sf image-width))
	 (binner
	  (cutoff-binner .01 pic-min pic-max (vector-length gray-map)))
	 (gray-pixel
	  (lambda (pixel-value)
	    (vector-ref gray-map (binner pixel-value)))))

    (cond ((and (fix:= 1 h-sf) (fix:= 1 v-sf))
	   (let y-loop ((py py-max) (iy-index 0))
	     (if (fix:<= 0 py)
		 (begin
		   (let ((pic-row (vector-ref pic-data py)))
		     (let x-loop ((px 0))
		       (if (fix:< px pic-width)
			   (begin
			     (write-pixel
			      pixels
			      (fix:+ px iy-index)
			      (gray-pixel (flo:vector-ref pic-row px)))
			     (x-loop (fix:+ px 1))))))
		   (y-loop (fix:- py 1) (fix:+ iy-index rect-index-height))))))

	  ((and (fix:= 2 h-sf) (fix:= 2 v-sf))
	   (let y-loop ((py py-max) (iy-index 0))
	     (if (fix:<= 0 py)
		 (let ((pic-row (vector-ref pic-data py)))
		   (let x-loop ((px 0) (ix 0))
		     (if (fix:< px pic-width)
			 (let* ((n-is-0 (fix:+ ix iy-index))
				(n-is-1 (fix:+ n-is-0 image-width))
				(v (gray-pixel (flo:vector-ref pic-row px))))
			   (write-pixel pixels n-is-0 v)
			   (write-pixel pixels (fix:+ n-is-0 1) v)
			   (write-pixel pixels n-is-1 v)
			   (write-pixel pixels (fix:+ n-is-1 1) v)
			   (x-loop (fix:+ px 1) (fix:+ ix h-sf)))
			 (y-loop (fix:- py 1)
				 (fix:+ iy-index rect-index-height))))))))

	  ((and (fix:= 3 h-sf) (fix:= 3 v-sf))
	   (let y-loop ((py py-max) (iy-index 0))
	     (if (fix:<= 0 py)
		 (let ((pic-row (vector-ref pic-data py)))
		   (let x-loop ((px 0) (ix 0))
		     (if (fix:< px pic-width)
			 (let* ((row0 (fix:+ ix iy-index))
				(row1 (fix:+ row0 image-width))
				(row2 (fix:+ row1 image-width))
				(v (gray-pixel (flo:vector-ref pic-row px))))
			   (write-pixel pixels row0 v)
			   (write-pixel pixels (fix:+ row0 1) v)
			   (write-pixel pixels (fix:+ row0 2) v)
			   (write-pixel pixels row1 v)
			   (write-pixel pixels (fix:+ row1 1) v)
			   (write-pixel pixels (fix:+ row1 2) v)
			   (write-pixel pixels row2 v)
			   (write-pixel pixels (fix:+ row2 1) v)
			   (write-pixel pixels (fix:+ row2 2) v)
			   (x-loop (fix:+ px 1) (fix:+ ix h-sf)))
			 (y-loop (fix:- py 1)
				 (fix:+ iy-index rect-index-height))))))))

	  ((and (fix:= 4 h-sf) (fix:= 4 v-sf))
	   (let y-loop ((py py-max) (iy-index 0))
	     (if (fix:<= 0 py)
		 (let ((pic-row (vector-ref pic-data py)))
		   (let x-loop ((px 0) (ix 0))
		     (if (fix:< px pic-width)
			 (let* ((row0 (fix:+ ix iy-index))
				(row1 (fix:+ row0 image-width))
				(row2 (fix:+ row1 image-width))
				(row3 (fix:+ row2 image-width))
				(v (gray-pixel (flo:vector-ref pic-row px))))
			   (write-pixel pixels row0 v)
			   (write-pixel pixels (fix:+ row0 1) v)
			   (write-pixel pixels (fix:+ row0 2) v)
			   (write-pixel pixels (fix:+ row0 3) v)
			   (write-pixel pixels row1 v)
			   (write-pixel pixels (fix:+ row1 1) v)
			   (write-pixel pixels (fix:+ row1 2) v)
			   (write-pixel pixels (fix:+ row1 3) v)
			   (write-pixel pixels row2 v)
			   (write-pixel pixels (fix:+ row2 1) v)
			   (write-pixel pixels (fix:+ row2 2) v)
			   (write-pixel pixels (fix:+ row2 3) v)
			   (write-pixel pixels row3 v)
			   (write-pixel pixels (fix:+ row3 1) v)
			   (write-pixel pixels (fix:+ row3 2) v)
			   (write-pixel pixels (fix:+ row3 3) v)
			   (x-loop (fix:+ px 1) (fix:+ ix h-sf)))
			 (y-loop (fix:- py 1)
				 (fix:+ iy-index rect-index-height))))))))

	  (else
	   (let y-loop ((py py-max) (iy-index 0))
	     (if (fix:<= 0 py)
		 (let ((pic-row (vector-ref pic-data py)))
		   (let x-loop ((px 0) (ix 0))
		     (if (fix:< px pic-width)
			 (let* ((v (gray-pixel (flo:vector-ref pic-row px)))
				(n-start (fix:+ ix iy-index))
				(n-end (fix:+ n-start rect-index-height)))
			   (let n-loop ((n n-start))
			     (if (fix:< n n-end)
				 (let ((m-end (fix:+ n h-sf)))
				   (let m-loop ((m n))
				     (if (fix:< m m-end)
					 (begin
					   (write-pixel pixels m v)
					   (m-loop (fix:+ m 1)))
					 (n-loop (fix:+ n image-width)))))
				 (x-loop (fix:+ px 1) (fix:+ ix h-sf)))))
			 (y-loop (fix:- py 1)
				 (fix:+ iy-index rect-index-height)))))))))
    ;; Kludge: IMAGE/FILL-FROM-BYTE-VECTOR should take an argument
    ;; that specifies what color a given byte in PIXELS maps to.
    (image/fill-from-byte-vector image pixels)
    (1d-table/put! (graphics-device/properties window) image (cons h-sf v-sf))
    image))