From a7963fe8dba2d7fc009a4e4a21331d76f9fae08a Mon Sep 17 00:00:00 2001
From: Glen Whitney <gwhitney@post.harvard.edu>
Date: Sat, 8 Sep 2018 21:37:05 -0400
Subject: [PATCH] First (incomplete) efforts toward a Circle3DObject class.

---
 rene/zirkel/docs/ZirkelProperties.properties |   1 +
 rene/zirkel/objects/Circle3DObject.java      | 125 +++++++++++++++++++
 2 files changed, 126 insertions(+)
 create mode 100644 rene/zirkel/objects/Circle3DObject.java

diff --git a/rene/zirkel/docs/ZirkelProperties.properties b/rene/zirkel/docs/ZirkelProperties.properties
index 955743c..bbd22e8 100644
--- a/rene/zirkel/docs/ZirkelProperties.properties
+++ b/rene/zirkel/docs/ZirkelProperties.properties
@@ -508,6 +508,7 @@ text.circle=Circle around % through %
 text.circle.fixed=Circle around % through % with radius %
 text.fixedcircle=Circle around % with radius %
 text.circle3=Circle around % with radius from % to %
+text.circle3d=3D Circle around % with radius % and normal %
 text.parallel=Parallel line through % to %
 text.midpoint=Midpoint between % and %
 text.quadric=Conic section through %
diff --git a/rene/zirkel/objects/Circle3DObject.java b/rene/zirkel/objects/Circle3DObject.java
new file mode 100644
index 0000000..37f179f
--- /dev/null
+++ b/rene/zirkel/objects/Circle3DObject.java
@@ -0,0 +1,125 @@
+/*
+
+Coyright 2018 Glen Whitney
+
+This file is contributed to C.a.R./CaRMetal software.
+
+    C.a.R. is a free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, version 3 of the License.
+
+    C.a.R. is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ 
+ */
+
+package rene.zirkel.objects;
+
+import rene.gui.Global;
+import rene.zirkel.construction.Construction;
+import rene.zirkel.construction.ConstructionException;
+import rene.zirkel.expression.Expression;
+
+/* A three dimensional circle determined by a 3D point (the "midpoint" of the super
+   object), an expression giving its radius, and a TwoPointLineObject
+   determined by two 3D points, giving its normal direction. (The line does
+   not have to go through the center.
+*/
+public class Circle3DObject extends PrimitiveCircleObject {
+    Expression E_R; // Expression for the radius
+    TwoPointLineObject N;
+
+    public Circle3DObject(final Construction c, final PointObject C,
+			  final String s, final TwoPointLineObject L)
+    throws ConstructionException {
+	super(c, C);
+	if (!C.is3D()) {
+	    throw new ConstructionException("Cannot create Circle3D with "
+					    + "non-3D center " +  C.getName());
+	}
+	if (!L.getP1().is3D() || !L.getP2().is3D()) {
+	    throw new ConstructionException("Cannot create Circle3D with "
+					    + "non-3D normal " + L.getName());
+	}
+	E_R = new Expression(s, c, this);
+	N = L;
+	validate();
+	updateText();
+    }
+
+    @Override
+    public String getTag() {
+	return "Circle3D";
+    }
+
+    @Override
+    public void updateText() {
+	setText(text3(Global.name("text.circle3D"),
+		      M.getName(), E_R.toString(), N.getName()));
+    }
+
+    @Override
+    public void validate() {
+	super.validate();
+	Valid = false;
+	if (!M.valid() || !E_R.valid() || !N.valid()) {
+	    return;
+	}
+	try { R = E_R.getValue(); } catch (final Exception e) {
+	    R = 0;
+	    return;
+	}
+	if (R < 0) { return; }
+	Valid = true;
+    }
+
+    @Override
+    public void printArgs(final XmlWriter xml) {
+	xml.printArg("radius", E_R.toString());
+	xml.printArg("normal", N.getName());
+	super.printArgs(xml);
+    }
+
+    @Override
+    public String getStringLength() {
+	return E_R.toString();
+    }
+
+    @Override
+    public double getValue() throws ConstructionException {
+	if (!Valid) {
+	    throw new InvalidException("exception.invalid");
+	} else {
+	    return R;
+	}
+    }
+
+    @Override
+    public Enumeration depending() {
+	super.depending();
+	final Enumeration e = E_R.getDepList().elements();
+	while (e.hasMoreElements()) {
+	    DL.add((ConstructionObject) e.nextElement());
+	}
+	DL.add(N);
+	return DL.elements();
+    }
+
+    /* A (rudimentary version) of the class is almost done at this point, but
+       it still needs a paint() method. This we want to share with the
+       QuadricObject. The best way I could think of was to create a class that
+       encapsulates the X[..] data in QuadricObject, with a method to set that
+       up from 5 (x,y) pairs. In QuadricObject, I woul just use the 5 (x,y)
+       values of the Point members. Here, in validate, I would use the center,
+       radius, and normal data to compute 5 equally-spaced (x,y,z) coordinates
+       around the circle. The sticking point is then projecting those to
+       (x,y). There does not seem to be any good way to do it -- it seems like
+       Expressions that do it are littered all around the code. Ugh. So I am
+       giving up for now. 
+    */
+}