From 8a71c6ec25766967c20e27cfd6a0d44abde85a57 Mon Sep 17 00:00:00 2001
From: Karsten Schmidt <k@postspectacular.com>
Date: Sat, 30 Jan 2021 16:26:14 +0000
Subject: [PATCH] fix(color): div-by-zero in XYY<>XYZ conversions

---
 packages/color/src/xyy/xyy-xyz.ts |  5 +++--
 packages/color/src/xyz/xyz-xyy.ts | 13 ++++++++++---
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/packages/color/src/xyy/xyy-xyz.ts b/packages/color/src/xyy/xyy-xyz.ts
index 40d4927cc5..57e949775c 100644
--- a/packages/color/src/xyy/xyy-xyz.ts
+++ b/packages/color/src/xyy/xyy-xyz.ts
@@ -1,3 +1,4 @@
+import { safeDiv } from "@thi.ng/math";
 import { setC4 } from "@thi.ng/vectors";
 import type { ColorOp } from "../api";
 import { ensureAlpha } from "../internal/ensure-alpha";
@@ -14,9 +15,9 @@ export const xyyXyz: ColorOp = (out, src) => {
     const { 0: x, 1: y, 2: Y } = src;
     return setC4(
         out || src,
-        (Y * x) / y,
+        safeDiv(Y * x, y),
         Y,
-        (Y * (1 - x - y)) / y,
+        safeDiv(Y * (1 - x - y), y),
         ensureAlpha(src[3])
     );
 };
diff --git a/packages/color/src/xyz/xyz-xyy.ts b/packages/color/src/xyz/xyz-xyy.ts
index 499bfbca24..43e3450cda 100644
--- a/packages/color/src/xyz/xyz-xyy.ts
+++ b/packages/color/src/xyz/xyz-xyy.ts
@@ -1,3 +1,4 @@
+import { safeDiv } from "@thi.ng/math";
 import { setC4 } from "@thi.ng/vectors";
 import type { ColorOp } from "../api";
 import { ensureAlpha } from "../internal/ensure-alpha";
@@ -11,7 +12,13 @@ import { ensureAlpha } from "../internal/ensure-alpha";
  * @param src
  */
 export const xyzXyy: ColorOp = (out, src) => {
-    const { 0: x, 1: y } = src;
-    const invSum = 1 / (x + y + src[2]);
-    return setC4(out || src, x * invSum, y * invSum, y, ensureAlpha(src[3]));
+    const { 0: x, 1: Y } = src;
+    const sum = x + Y + src[2];
+    return setC4(
+        out || src,
+        safeDiv(x, sum),
+        safeDiv(Y, sum),
+        Y,
+        ensureAlpha(src[3])
+    );
 };