From ddbfc458d7ef77a807b987da16f3bb29062c49aa Mon Sep 17 00:00:00 2001
From: Matt Weiden <538456+mweiden@users.noreply.github.com>
Date: Tue, 14 Jan 2020 13:46:53 -0800
Subject: [PATCH] Remove d3 dependency in crossfilter (#1108)

* Remove d3 dependency in crossfilter

Fixes https://github.com/chanzuckerberg/cellxgene/issues/648

* Revert "Remove d3 dependency in crossfilter"

This reverts commit 03b478f7dc9bfa0a097e530bb84322fce224beb4.

* Remove d3 dependency in crossfilter

Fixes https://github.com/chanzuckerberg/cellxgene/issues/648

* Fix typo in docstring
---
 .../util/typedCrossfilter/crossfilter.test.js | 18 ++++++-----
 client/src/reducers/undoable.js               |  4 +--
 .../src/util/typedCrossfilter/crossfilter.js  | 30 ++++++++++++++++---
 3 files changed, 39 insertions(+), 13 deletions(-)

diff --git a/client/__tests__/util/typedCrossfilter/crossfilter.test.js b/client/__tests__/util/typedCrossfilter/crossfilter.test.js
index 0558741c..9fd4e298 100644
--- a/client/__tests__/util/typedCrossfilter/crossfilter.test.js
+++ b/client/__tests__/util/typedCrossfilter/crossfilter.test.js
@@ -1,5 +1,4 @@
 import _ from "lodash";
-import { polygonContains } from "d3";
 
 import Crossfilter from "../../../src/util/typedCrossfilter";
 
@@ -334,12 +333,17 @@ describe("ImmutableTypedCrossfilter", () => {
     );
 
     test.each([
-      [[[0, 0], [0, 1], [1, 1], [1, 0]]],
-      [[[0, 0], [0, 0.5], [0.5, 0.5], [0.5, 0]]]
-    ])("within-polygon %p", polygon => {
-      expect(
-        p.select("coords", { mode: "within-polygon", polygon }).allSelected()
-      ).toEqual(_.filter(someData, d => polygonContains(polygon, d.coords)));
+      [
+          [[0, 0], [0, 1], [1, 1], [1, 0]],
+          [true, true, true, true, true, false, true, true, true, true, true, true]
+      ],
+      [
+          [[0, 0], [0, 0.5], [0.5, 0.5], [0.5, 0]],
+          [true, true, true, true, false, false, false, true, true, true, false, false]
+      ]
+    ])("within-polygon %p", (polygon, expected) => {
+      expect(p.select("coords", { mode: "within-polygon", polygon }).allSelected())
+          .toEqual(_.zip(someData, expected).filter(x => x[1]).map(x => x[0]));
     });
   });
 
diff --git a/client/src/reducers/undoable.js b/client/src/reducers/undoable.js
index 3a435f34..803b74e0 100644
--- a/client/src/reducers/undoable.js
+++ b/client/src/reducers/undoable.js
@@ -1,9 +1,9 @@
 /*
-A redo/undo meta reducer for Redux.   Designed to work well with the cascadeReducer().
+A redo/undo meta reducer for Redux.  Designed to work well with the cascadeReducer().
 
 Requires three parameters:
 * reducer - a reducer, which MUST return an object as state.
-* undoableKeys - an array of object keys (strings).   If any of these keys
+* undoableKeys - an array of object keys (strings).  If any of these keys
   are in the object/state returned by the reducer, they will be treated as
   state to be made "undoable".
 * options - an optional object, which may contain the following parameters:
diff --git a/client/src/util/typedCrossfilter/crossfilter.js b/client/src/util/typedCrossfilter/crossfilter.js
index 67a2b487..9d6976a7 100644
--- a/client/src/util/typedCrossfilter/crossfilter.js
+++ b/client/src/util/typedCrossfilter/crossfilter.js
@@ -1,5 +1,3 @@
-import { polygonContains } from "d3";
-
 import PositiveIntervals from "./positiveIntervals";
 import BitArray from "./bitArray";
 import {
@@ -662,7 +660,31 @@ function polygonBoundingBox(polygon) {
   return [minX, minY, maxX, maxY];
 }
 
+/**
+ *  withinPolygon determines if a point is within a polygon
+ *  Code adapted from https://github.com/d3/d3-polygon/blob/master/src/contains.js
+ *  @param {array} polygon - is an array of point arrays of format [[x1, y1], [x2, y2], ...]
+ *  @param {float} x - point x coordinate
+ *  @param {float} y - point y coordinate
+ *  @type {boolean}
+ */
 function withinPolygon(polygon, x, y) {
-  // TODO XXX replace
-  return polygonContains(polygon, [x, y]);
+  const n = polygon.length;
+  let p = polygon[n - 1];
+  let x0 = p[0];
+  let y0 = p[1];
+  let x1;
+  let y1;
+  let inside = false;
+
+  for (let i = 0; i < n; i += 1) {
+    p = polygon[i];
+    x1 = p[0];
+    y1 = p[1];
+
+    if (((y1 > y) !== (y0 > y)) && (x < (x0 - x1) * (y - y1) / (y0 - y1) + x1)) inside = !inside;
+    x0 = x1;
+    y0 = y1;
+  }
+  return inside;
 }