[spaces/prophoto] Use 64 bit-accurate conversion matrices

color-js · Dec 18, 2023 · f750d09 · f750d09
1 parent efb6e7d
commit f750d09
Showing 1 changed file with 8 additions and 7 deletions.
diff --git a/src/spaces/prophoto-linear.js b/src/spaces/prophoto-linear.js
@@ -3,17 +3,18 @@ import XYZ_D50 from "./xyz-d50.js";
 
 // convert an array of  prophoto-rgb values to CIE XYZ
 // using  D50 (so no chromatic adaptation needed afterwards)
-// http://www.brucelindbloom.com/index.html?Eqn_RGB_XYZ_Matrix.html
+// matrix cannot be expressed in rational form, but is calculated to 64 bit accuracy
+// see https://github.com/w3c/csswg-drafts/issues/7675
 const toXYZ_M = [
-	[ 0.7977604896723027,  0.13518583717574031,  0.0313493495815248     ],
-	[ 0.2880711282292934,  0.7118432178101014,   0.00008565396060525902 ],
-	[ 0.0,                 0.0,                  0.8251046025104601     ]
+	[ 0.79776664490064230,  0.13518129740053308,  0.03134773412839220 ],
+	[ 0.28807482881940130,  0.71183523424187300,  0.00008993693872564 ],
+	[ 0.00000000000000000,  0.00000000000000000,  0.82510460251046020 ]
 ];
 
 const fromXYZ_M = [
-	[  1.3457989731028281,  -0.25558010007997534,  -0.05110628506753401 ],
-	[ -0.5446224939028347,   1.5082327413132781,    0.02053603239147973 ],
-	[  0.0,                  0.0,                   1.2119675456389454  ]
+	[  1.34578688164715830, -0.25557208737979464, -0.05110186497554526 ],
+	[ -0.54463070512490190,  1.50824774284514680,  0.02052744743642139 ],
+	[  0.00000000000000000,  0.00000000000000000,  1.21196754563894520 ]
 ];
 
 export default new RGBColorSpace({