From 2d0f48bfc6eef2974447ab1a7cf1de744194d18a Mon Sep 17 00:00:00 2001
From: Joost De Cock <joost@decock.org>
Date: Mon, 3 Sep 2018 12:07:02 +0200
Subject: [PATCH] :sparkles: Switch to curve.edge for finding path edge

---
 src/path.js        | 28 +++-------------------------
 src/utils.js       | 22 ++++++++++++++++++++++
 tests/path.test.js | 25 ++++++++++++++++++++-----
 3 files changed, 45 insertions(+), 30 deletions(-)

diff --git a/src/path.js b/src/path.js
index 4f05eb88253..a98d42fe423 100644
--- a/src/path.js
+++ b/src/path.js
@@ -7,6 +7,7 @@ import {
   curvesIntersect,
   pointOnLine,
   pointOnCurve,
+  curveEdge,
   round
 } from "./utils";
 
@@ -484,31 +485,8 @@ Path.prototype.edge = function(side) {
         else return this.rightOp.from;
       }
     } else if (this[s].type === "curve") {
-      let line;
-      if (side === "top")
-        line = {
-          p1: { x: this.topLeft.x, y: this.topLeft.y },
-          p2: { x: this.bottomRight.x, y: this.topLeft.y }
-        };
-      else if (side === "left")
-        line = {
-          p1: { x: this.topLeft.x, y: this.topLeft.y },
-          p2: { x: this.topLeft.x, y: this.bottomRight.y }
-        };
-      else if (side === "bottom")
-        line = {
-          p1: { x: this.topLeft.x, y: this.bottomRight.y },
-          p2: { x: this.bottomRight.x, y: this.bottomRight.y }
-        };
-      else if (side === "right")
-        line = {
-          p1: { x: this.bottomRight.x, y: this.topLeft.y },
-          p2: { x: this.bottomRight.x, y: this.bottomRight.y }
-        };
-      let bz = edgeCurveAsBezier(this[s]);
-      let isect = bz.intersects(line);
-      let edge = bz.get(isect[0]);
-      return new Point(edge.x, edge.y);
+      let curve = edgeCurveAsBezier(this[s]);
+      return curveEdge(curve, side);
     }
   }
 };
diff --git a/src/utils.js b/src/utils.js
index 40730c392df..01478e50a9a 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -259,6 +259,28 @@ export function lineIntersectsCircle(c, r, p1, p2, sort = "x") {
   }
 }
 
+export function curveEdge(curve, edge, steps = 500) {
+  let x = Infinity;
+  let y = Infinity;
+  let p;
+  if (edge === "bottom") y = -Infinity;
+  if (edge === "right") x = -Infinity;
+  for (let i = 0; i < steps; i++) {
+    p = curve.get(i / steps);
+    if (
+      (edge === "top" && p.y < y) ||
+      (edge === "bottom" && p.y > y) ||
+      (edge === "right" && p.x > x) ||
+      (edge === "left" && p.x < x)
+    ) {
+      x = p.x;
+      y = p.y;
+    }
+  }
+
+  return new Point(x, y);
+}
+
 /**
  * Calculates scale factor based on stretch factor
  *
diff --git a/tests/path.test.js b/tests/path.test.js
index 4ccafd4373b..4b9c8b6665a 100644
--- a/tests/path.test.js
+++ b/tests/path.test.js
@@ -357,12 +357,12 @@ it("Should find the edges of a path", () => {
   expect(round(a.paths.test.edge("topRight").x)).to.equal(90);
   expect(round(a.paths.test.edge("topRight").y)).to.equal(0.97);
   expect(round(a.paths.test.edge("left").x)).to.equal(7.7);
-  expect(round(a.paths.test.edge("left").y)).to.equal(91.7);
-  expect(round(a.paths.test.edge("bottom").x)).to.equal(40.75);
+  expect(round(a.paths.test.edge("left").y)).to.equal(91.8);
+  expect(round(a.paths.test.edge("bottom").x)).to.equal(40.63);
   expect(round(a.paths.test.edge("bottom").y)).to.equal(118.46);
-  expect(round(a.paths.test.edge("right").x)).to.equal(90);
-  expect(round(a.paths.test.edge("right").y)).to.equal(30);
-  expect(round(a.paths.test.edge("top").x)).to.equal(55.97);
+  expect(round(a.paths.test.edge("right").x)).to.equal(89.76);
+  expect(round(a.paths.test.edge("right").y)).to.equal(29.64);
+  expect(round(a.paths.test.edge("top").x)).to.equal(55.98);
   expect(round(a.paths.test.edge("top").y)).to.equal(0.97);
 });
 
@@ -393,6 +393,21 @@ it("Should find the edges of a path for corner cases", () => {
   expect(round(a.paths.test.edge("right").y)).to.equal(60);
 });
 
+it("Should find the edge of a path for this edge-case", () => {
+  let pattern = new freesewing.Pattern();
+  pattern.parts.a = new pattern.Part();
+  let a = pattern.parts.a;
+  a.points.A = new a.Point(-109.7, 77, 12);
+  a.points.B = new a.Point(-27.33, 99.19);
+  a.points.C = new a.Point(-39.45, 137.4);
+  a.points.D = new a.Point(-61.52, 219.77);
+  a.paths.test = new a.Path()
+    .move(a.points.A)
+    .curve(a.points.B, a.points.C, a.points.D);
+  expect(round(a.paths.test.edge("right").x)).to.equal(-45.22);
+  expect(round(a.paths.test.edge("right").y)).to.equal(139.4);
+});
+
 it("Should find where a path intersects with an X value", () => {
   let pattern = new freesewing.Pattern();
   pattern.parts.a = new pattern.Part();