From a078113e6bf4122fa0fd037a1cf4866bc029fba2 Mon Sep 17 00:00:00 2001
From: Chris Lilley <chris@w3.org>
Date: Wed, 10 Aug 2022 15:23:41 +0300
Subject: [PATCH] [contrast] Weber returns a clamped max, not zero, if Y2 === 0

---
 src/contrast/Weber.js | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/contrast/Weber.js b/src/contrast/Weber.js
index ecb9b0057..c70cdf50d 100644
--- a/src/contrast/Weber.js
+++ b/src/contrast/Weber.js
@@ -6,6 +6,12 @@
 import getColor from "../getColor.js";
 import {getLuminance} from "../luminance.js";
 
+// the darkest sRGB color above black is #000001 and this produces
+// a plain Weber contrast of ~45647.
+// So, setting the divide-by-zero result at 50000 is a reasonable
+// max clamp for the plain Weber
+const max = 50000;
+
 export default function contrastWeber (color1, color2) {
 	color1 = getColor(color1);
 	color2 = getColor(color2);
@@ -17,5 +23,5 @@ export default function contrastWeber (color1, color2) {
 		[Y1, Y2] = [Y2, Y1];
 	}
 
-	return Y2 === 0 ? 0 : (Y1 - Y2) / Y2;
-};
\ No newline at end of file
+	return Y2 === 0 ? max : (Y1 - Y2) / Y2;
+};