1 files changed, 71 insertions, 0 deletions
diff --git a/sys/plio/plpolygon.x b/sys/plio/plpolygon.x
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+++ b/sys/plio/plpolygon.x
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+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include <plset.h>
+include <plio.h>
+include "plpolygon.h"
+
+
+# PL_POLYGON -- Perform a rasterop operation on the area enclosed by a polygon
+# drawn in a 2-dimensional plane of a mask.  If the dimensionality of the mask
+# exceeds 2, the pl_setplane() procedure should be called first to define the
+# plane of the mask to be modified.
+
+procedure pl_polygon (pl, x, y, npts, rop)
+
+pointer	pl			#I mask descriptor
+int	x[npts]			#I polygon x-vertices
+int	y[npts]			#I polygon y-vertices
+int	npts			#I number of points in polygon
+int	rop			#I rasterop defining operation
+
+int	line_1, line_2, i
+pointer	sp, ufd, xp, yp, oo
+extern	pl_upolygon()
+errchk	plvalid
+
+begin
+	call plvalid (pl)
+	if (npts <= 0)
+	    return
+	else if (npts == 1) {
+	    call pl_point (pl, x[1], y[1], rop)
+	    return
+	}
+
+	call smark (sp)
+	call salloc (ufd, LEN_PGONDES, TY_STRUCT)
+	call salloc (oo, RL_FIRST + (npts+1)*3, TY_INT)
+	call salloc (xp, npts + 1, TY_REAL)
+	call salloc (yp, npts + 1, TY_REAL)
+
+	# Initialize the region descriptor.
+	P_PL(ufd) = pl
+	P_XP(ufd) = xp
+	P_YP(ufd) = yp
+	P_PV(ufd) = 1
+	P_OO(ufd) = oo
+	P_OY(ufd) = -1
+	P_NS(ufd) = npts - 1
+	RLI_LEN(oo) = 0
+
+	# Copy the user supplied polygon vertices into the descriptor,
+	# normalizing the polygon in the process.
+
+	do i = 1, npts {
+	    Memr[xp+i-1] = x[i]
+	    Memr[yp+i-1] = y[i]
+	}
+
+	if (npts > 2)
+	    if (abs(x[1]-x[npts]) > TOL || abs(y[1]-y[npts]) > TOL) {
+		Memr[xp+npts] = x[1]
+		Memr[yp+npts] = y[1]
+		P_NS(ufd) = npts
+	    }
+
+	# Compute the range in Y in which the polygon should be drawn.
+	call alimi (y, npts, line_1, line_2)
+
+	call pl_regionrop (pl, pl_upolygon, ufd, line_1, line_2, rop)
+	call sfree (sp)
+end