move lineIntersect -> Lib.geometry2d

Author: alexcjohnson

src/components/annotations/draw.js

@@ -487,15 +487,15 @@ function drawRaw(gd, options, index, subplotId, xa, ya) {
             // to get the parity of the number of intersections.
             if(edges.reduce(function(a, x) {
                 return a ^
-                    !!lineIntersect(headX, headY, headX + 1e6, headY + 1e6,
+                    !!Lib.segmentsIntersect(headX, headY, headX + 1e6, headY + 1e6,
                             x[0], x[1], x[2], x[3]);
             }, false)) {
                 // no line or arrow - so quit drawArrow now
                 return;
             }
 
             edges.forEach(function(x) {
-                var p = lineIntersect(tailX, tailY, headX, headY,
+                var p = Lib.segmentsIntersect(tailX, tailY, headX, headY,
                             x[0], x[1], x[2], x[3]);
                 if(p) {
                     tailX = p.x;
@@ -701,24 +701,3 @@ function drawRaw(gd, options, index, subplotId, xa, ya) {
     }
     else annText.call(textLayout);
 }
-
-// look for intersection of two line segments
-//   (1->2 and 3->4) - returns array [x,y] if they do, null if not
-function lineIntersect(x1, y1, x2, y2, x3, y3, x4, y4) {
-    var a = x2 - x1,
-        b = x3 - x1,
-        c = x4 - x3,
-        d = y2 - y1,
-        e = y3 - y1,
-        f = y4 - y3,
-        det = a * f - c * d;
-    // parallel lines? intersection is undefined
-    // ignore the case where they are colinear
-    if(det === 0) return null;
-    var t = (b * f - c * e) / det,
-        u = (b * d - a * e) / det;
-    // segments do not intersect?
-    if(u < 0 || u > 1 || t < 0 || t > 1) return null;
-
-    return {x: x1 + a * t, y: y1 + d * t};
-}

src/lib/geometry2d.js

@@ -0,0 +1,32 @@
+/**
+* Copyright 2012-2017, Plotly, Inc.
+* All rights reserved.
+*
+* This source code is licensed under the MIT license found in the
+* LICENSE file in the root directory of this source tree.
+*/
+
+'use strict';
+
+/*
+ * look for intersection of two line segments
+ *   (1->2 and 3->4) - returns array [x,y] if they do, null if not
+ */
+exports.segmentsIntersect = function segmentsIntersect(x1, y1, x2, y2, x3, y3, x4, y4) {
+    var a = x2 - x1,
+        b = x3 - x1,
+        c = x4 - x3,
+        d = y2 - y1,
+        e = y3 - y1,
+        f = y4 - y3,
+        det = a * f - c * d;
+    // parallel lines? intersection is undefined
+    // ignore the case where they are colinear
+    if(det === 0) return null;
+    var t = (b * f - c * e) / det,
+        u = (b * d - a * e) / det;
+    // segments do not intersect?
+    if(u < 0 || u > 1 || t < 0 || t > 1) return null;
+
+    return {x: x1 + a * t, y: y1 + d * t};
+};

src/lib/index.js

@@ -74,6 +74,10 @@ lib.rotationXYMatrix = matrixModule.rotationXYMatrix;
 lib.apply2DTransform = matrixModule.apply2DTransform;
 lib.apply2DTransform2 = matrixModule.apply2DTransform2;
 
+var geom2dModule = require('./geometry2d');
+lib.segmentsIntersect = geom2dModule.segmentsIntersect;
+lib.segmentDistance = geom2dModule.segmentDistance;
+
 var extendModule = require('./extend');
 lib.extendFlat = extendModule.extendFlat;
 lib.extendDeep = extendModule.extendDeep;