From 718f7f56df309582af1a183831a3123f79fa8d70 Mon Sep 17 00:00:00 2001
From: Pekka Paalanen <pekka.paalanen@collabora.com>
Date: Fri, 25 Apr 2025 16:44:33 +0300
Subject: [PATCH] tests/color_util: add power-2.2 transfer function

This is needed by the next commit.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
---
 tests/color_util.c | 28 ++++++++++++++++++++++++++++
 tests/color_util.h |  2 ++
 2 files changed, 30 insertions(+)

diff --git a/tests/color_util.c b/tests/color_util.c
index 86b59a596..27a2627d3 100644
--- a/tests/color_util.c
+++ b/tests/color_util.c
@@ -114,6 +114,20 @@ AdobeRGB_EOTF_inv(float o)
 	return pow(o, 256./563.);
 }
 
+static float
+Power2_2_EOTF(float e)
+{
+	e = ensure_unit_range(e);
+	return pow(e, 2.2);
+}
+
+static float
+Power2_2_EOTF_inv(float o)
+{
+	o = ensure_unit_range(o);
+	return pow(o, 1./2.2);
+}
+
 static float
 Power2_4_EOTF(float e)
 {
@@ -169,6 +183,20 @@ static const struct tone_curve_info tone_curves[] = {
 		.apply = AdobeRGB_EOTF_inv,
 		.lcms2 = { -1, { 563./256., 0.0, 0.0, 0.0 , 0.0 }},
 	},
+	[TRANSFER_FN_POWER2_2_EOTF] = {
+		.fn = TRANSFER_FN_POWER2_2_EOTF,
+		.name = "power 2.2",
+		.inv_fn = TRANSFER_FN_POWER2_2_EOTF_INVERSE,
+		.apply = Power2_2_EOTF,
+		.lcms2 = { 1, { 2.2, 0.0, 0.0, 0.0 , 0.0 }},
+	},
+	[TRANSFER_FN_POWER2_2_EOTF_INVERSE] = {
+		.fn = TRANSFER_FN_POWER2_2_EOTF_INVERSE,
+		.name = "inverse power 2.2",
+		.inv_fn = TRANSFER_FN_POWER2_2_EOTF,
+		.apply = Power2_2_EOTF_inv,
+		.lcms2 = { -1, { 2.2, 0.0, 0.0, 0.0 , 0.0 }},
+	},
 	[TRANSFER_FN_POWER2_4_EOTF] = {
 		.fn = TRANSFER_FN_POWER2_4_EOTF,
 		.name = "power 2.4",
diff --git a/tests/color_util.h b/tests/color_util.h
index fabb09b47..1abb890d7 100644
--- a/tests/color_util.h
+++ b/tests/color_util.h
@@ -56,6 +56,8 @@ enum transfer_fn {
 	TRANSFER_FN_SRGB_INVERSE,
 	TRANSFER_FN_ADOBE_RGB_EOTF,
 	TRANSFER_FN_ADOBE_RGB_EOTF_INVERSE,
+	TRANSFER_FN_POWER2_2_EOTF,
+	TRANSFER_FN_POWER2_2_EOTF_INVERSE,
 	TRANSFER_FN_POWER2_4_EOTF,
 	TRANSFER_FN_POWER2_4_EOTF_INVERSE,
 };