From 85fc150957ed12a545f63439d3e5bd6a6a36c803 Mon Sep 17 00:00:00 2001
From: Myndex <perceptex@myndex.com>
Date: Fri, 8 Dec 2023 15:31:03 -0800
Subject: [PATCH] fix: corrected threshold for luminance (#472)

The correct threshold is 0.04045, as recited in the official IEC standard for sRGB. And while it was incorrect (0.03928) for a long time in WCAG2, it was corrected by the W3 AGWG in May 2021.

Current WCAG 2.1 and 2.2 reflect the correct 0.04045 threshold.

Co-authored-by: Rico Kahler <ricokahler@gmail.com>
---
 src/getLuminance.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/getLuminance.ts b/src/getLuminance.ts
index 9f2f7bd..e316c78 100644
--- a/src/getLuminance.ts
+++ b/src/getLuminance.ts
@@ -10,7 +10,7 @@ function getLuminance(color: string): number {
 
   function f(x: number) {
     const channel = x / 255;
-    return channel <= 0.03928
+    return channel <= 0.04045
       ? channel / 12.92
       : Math.pow(((channel + 0.055) / 1.055), 2.4);
   }