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diff --git a/pkg/plot/vport.x b/pkg/plot/vport.x
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+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include <gset.h>
+
+define	XCEN	0.5
+define	YCEN	0.52
+define	EDGE1	0.1
+define	EDGE2	0.93
+
+# PL_MAP_VIEWPORT -- set device viewport for contour and hafton plots.  If not
+# specified by user, a default viewport centered on the device is used.
+#
+# The value of "extreme" (ext) axes ratios changed from 1/4 to 1/16 
+# (ShJ 6-10-88)
+
+procedure pl_map_viewport (gp, ncols, nlines, ux1, ux2, uy1, uy2, fill, perim)
+
+pointer	gp			#I pointer to graphics descriptor
+int	ncols, nlines		#I size of image area, after block reduction
+real	ux1, ux2, uy1, uy2	#I NDC coordinates of requested viewort
+bool	fill			#I fill viewport (vs preserve aspect ratio)
+bool	perim			#I draw perimeter
+
+real	xcen, ycen
+real	ncolsr, nlinesr, ratio, aspect_ratio
+real	x1, x2, y1, y2, ext, xdis, ydis
+data    ext /0.0625/
+bool	fp_equalr()
+real	ggetr()
+
+begin
+	ncolsr = real (ncols)
+	nlinesr = real (nlines)
+
+	if (fp_equalr (ux1, 0.0) && fp_equalr (ux2, 0.0) && 
+	    fp_equalr (uy1, 0.0) && fp_equalr (uy2, 0.0)) {
+
+	    if (fill && !perim) {
+		x1 = 0.0;  x2 = 1.0
+		y1 = 0.0;  y2 = 1.0
+		xcen = 0.5;  ycen = 0.5
+	    } else {
+		x1 = EDGE1;  x2 = EDGE2
+		y1 = EDGE1;  y2 = EDGE2
+		xcen = XCEN;  ycen = YCEN
+	    }
+
+	    # Calculate optimum viewport, as in NCAR's conrec, hafton.
+	    if (!fill) {
+		ratio = min (ncolsr, nlinesr) / max (ncolsr, nlinesr)
+		if (ratio >= ext) {
+		    if (ncols > nlines) 
+			y2 = (y2 - y1) * nlinesr / ncolsr + y1
+		    else 
+			x2 = (x2 - x1) * ncolsr / nlinesr + x1
+		}
+	    }
+
+	    xdis = x2 - x1
+	    ydis = y2 - y1
+
+	    # So far, the viewport has been calculated so that equal numbers of
+	    # image pixels map to equal distances in NDC space, regardless of 
+	    # the aspect ratio of the device.  If the parameter "fill" has been
+	    # set to no, the user wants to compensate for a non-unity aspect 
+	    # ratio and make equal numbers of image pixels map to into the same 
+	    # physical distance on the device, not the same NDC distance.
+
+	    if (!fill) {
+	        aspect_ratio = ggetr (gp, "ar")
+
+	        if (fp_equalr (aspect_ratio, 0.0))
+	            aspect_ratio = 1.0
+
+		if (aspect_ratio < 1.0)
+		    # Landscape
+	            xdis = xdis * aspect_ratio
+		else if (aspect_ratio > 1.0)
+		    # Portrait
+		    ydis = ydis / aspect_ratio
+	    }
+
+	    ux1 = xcen - (xdis / 2.0)
+	    ux2 = xcen + (xdis / 2.0)
+	    uy1 = ycen - (ydis / 2.0)
+	    uy2 = ycen + (ydis / 2.0)
+	}
+
+	# Set window and viewport for WCS 1
+	call gseti  (gp, G_WCS, 1)
+	call gsview (gp, ux1, ux2, uy1, uy2)
+	call gswind (gp, 1.0, ncolsr, 1.0, nlinesr)
+	call set (ux1, ux2, uy1, uy2, 1.0, ncolsr, 1.0, nlinesr, 1)
+end