1 files changed, 38 insertions, 0 deletions
diff --git a/pkg/images/imgeom/src/blkcomp.x b/pkg/images/imgeom/src/blkcomp.x
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+++ b/pkg/images/imgeom/src/blkcomp.x
@@ -0,0 +1,38 @@
+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include	<imhdr.h>
+
+# BLKCOMP -- compute starting and ending input vectors for blocks in each
+# dimension.  Initialize input-line vectors to block vectors.  Return total
+# number of input lines mapping to current output line.
+
+int procedure blkcomp (im1, blkfac, vout, blkin_s, blkin_e,
+		vin_s, vin_e)
+
+pointer	im1			# pointer to input image descriptor
+int	blkfac[IM_MAXDIM]	# blocking factors for each dimension
+long	vout[IM_MAXDIM]		# output image vectors for each dimension
+long	blkin_s[IM_MAXDIM]	# index of starting block for each dimension
+long	blkin_e[IM_MAXDIM]	# index of ending block for each dimension
+long	vin_s[IM_MAXDIM]	# initial starting input vector
+long	vin_e[IM_MAXDIM]	# initial ending input vector
+
+int	num_ilines, dim
+
+begin
+	num_ilines = 1
+
+	# Compute starting and ending indices of input image pixels in each
+	# dimension mapping to current output line.
+
+	do dim = 2, IM_NDIM(im1) {
+	    blkin_s[dim] = long(1 + (vout[dim] - 1) * blkfac[dim])
+	    blkin_e[dim] = long(min (IM_LEN(im1,dim), vout[dim] * blkfac[dim]))
+	    vin_s[dim]   = blkin_s[dim]
+	    vin_e[dim]   = blkin_s[dim]
+	    num_ilines = num_ilines * (blkin_e[dim] - blkin_s[dim] + 1)
+	}
+	
+	return (num_ilines)
+end
+