Restructuring GUI code - first pass - WIP.
diff --git a/web/gui/src/main/webapp/geometry2.js b/web/gui/src/main/webapp/geometry2.js
new file mode 100644
index 0000000..5ede643
--- /dev/null
+++ b/web/gui/src/main/webapp/geometry2.js
@@ -0,0 +1,123 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ Geometry library - based on work by Mike Bostock.
+ */
+
+(function() {
+
+    if (typeof geo == 'undefined') {
+        geo = {};
+    }
+
+    var tolerance = 1e-10;
+
+    function eq(a, b) {
+        return (Math.abs(a - b) < tolerance);
+    }
+
+    function gt(a, b) {
+        return (a - b > -tolerance);
+    }
+
+    function lt(a, b) {
+        return gt(b, a);
+    }
+
+    geo.eq = eq;
+    geo.gt = gt;
+    geo.lt = lt;
+
+    geo.LineSegment = function(x1, y1, x2, y2) {
+        this.x1 = x1;
+        this.y1 = y1;
+        this.x2 = x2;
+        this.y2 = y2;
+
+        // Ax + By = C
+        this.a = y2 - y1;
+        this.b = x1 - x2;
+        this.c = x1 * this.a + y1 * this.b;
+
+        if (eq(this.a, 0) && eq(this.b, 0)) {
+            throw new Error(
+                'Cannot construct a LineSegment with two equal endpoints.');
+        }
+    };
+
+    geo.LineSegment.prototype.intersect = function(that) {
+        var d = (this.x1 - this.x2) * (that.y1 - that.y2) -
+            (this.y1 - this.y2) * (that.x1 - that.x2);
+
+        if (eq(d, 0)) {
+            // The two lines are parallel or very close.
+            return {
+                x : NaN,
+                y : NaN
+            };
+        }
+
+        var t1  = this.x1 * this.y2 - this.y1 * this.x2,
+            t2  = that.x1 * that.y2 - that.y1 * that.x2,
+            x   = (t1 * (that.x1 - that.x2) - t2 * (this.x1 - this.x2)) / d,
+            y   = (t1 * (that.y1 - that.y2) - t2 * (this.y1 - this.y2)) / d,
+            in1 = (gt(x, Math.min(this.x1, this.x2)) && lt(x, Math.max(this.x1, this.x2)) &&
+                gt(y, Math.min(this.y1, this.y2)) && lt(y, Math.max(this.y1, this.y2))),
+            in2 = (gt(x, Math.min(that.x1, that.x2)) && lt(x, Math.max(that.x1, that.x2)) &&
+                gt(y, Math.min(that.y1, that.y2)) && lt(y, Math.max(that.y1, that.y2)));
+
+        return {
+            x   : x,
+            y   : y,
+            in1 : in1,
+            in2 : in2
+        };
+    };
+
+    geo.LineSegment.prototype.x = function(y) {
+        // x = (C - By) / a;
+        if (this.a) {
+            return (this.c - this.b * y) / this.a;
+        } else {
+            // a == 0 -> horizontal line
+            return NaN;
+        }
+    };
+
+    geo.LineSegment.prototype.y = function(x) {
+        // y = (C - Ax) / b;
+        if (this.b) {
+            return (this.c - this.a * x) / this.b;
+        } else {
+            // b == 0 -> vertical line
+            return NaN;
+        }
+    };
+
+    geo.LineSegment.prototype.length = function() {
+        return Math.sqrt(
+                (this.y2 - this.y1) * (this.y2 - this.y1) +
+                (this.x2 - this.x1) * (this.x2 - this.x1));
+    };
+
+    geo.LineSegment.prototype.offset = function(x, y) {
+        return new geo.LineSegment(
+                this.x1 + x, this.y1 + y,
+                this.x2 + x, this.y2 + y);
+    };
+
+})();