From eeb51449c4796b3d30c2b60dbda2ec1103fb317b Mon Sep 17 00:00:00 2001
From: Flo <flo@Mac.lan>
Date: Fri, 12 Dec 2025 19:38:52 +0100
Subject: [PATCH 1/3] Enable inverse gamma correction (gamma < 1.0)

Allow gamma values from 0.1 to 3.0 instead of restricting to > 1.0.
This enables inverse gamma curves for use cases requiring brightened
mid-tones and compressed highlights.

Changes:
- Update backend validation in set.cpp and cfg.cpp to accept 0.1-3.0
- Update HTML form min value from 1 to 0.1

The calcGammaTable() function already supports any gamma value
mathematically, so this just removes an artificial restriction.
---
 wled00/cfg.cpp                | 2 +-
 wled00/data/settings_leds.htm | 2 +-
 wled00/set.cpp                | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/wled00/cfg.cpp b/wled00/cfg.cpp
index 47ba152c96..1105101dfb 100644
--- a/wled00/cfg.cpp
+++ b/wled00/cfg.cpp
@@ -512,7 +512,7 @@ bool deserializeConfig(JsonObject doc, bool fromFS) {
   else                     gammaCorrectBri = false;
   if (light_gc_col > 1.0f) gammaCorrectCol = true;
   else                     gammaCorrectCol = false;
-  if (gammaCorrectVal <= 1.0f || gammaCorrectVal > 3) {
+  if (gammaCorrectVal < 0.1f || gammaCorrectVal > 3) {
     gammaCorrectVal = 1.0f; // no gamma correction
     gammaCorrectBri = false;
     gammaCorrectCol = false;
diff --git a/wled00/data/settings_leds.htm b/wled00/data/settings_leds.htm
index 47c4f514d8..f683c964f1 100644
--- a/wled00/data/settings_leds.htm
+++ b/wled00/data/settings_leds.htm
@@ -937,7 +937,7 @@ <h3>Defaults</h3>
 		Apply preset <input name="BP" type="number" class="m" min="0" max="250" required> at boot (0 uses values from above)<br><br>
 		Use Gamma correction for color: <input type="checkbox" name="GC"> (strongly recommended)<br>
 		Use Gamma correction for brightness: <input type="checkbox" name="GB"> (not recommended)<br>
-		Use Gamma value: <input name="GV" type="number" class="m" placeholder="2.8" min="1" max="3" step="0.1" required><br><br>
+		Use Gamma value: <input name="GV" type="number" class="m" placeholder="2.8" min="0.1" max="3" step="0.1" required><br><br>
 		Brightness factor: <input name="BF" type="number" class="m" min="1" max="255" required> %
 		<h3>Transitions</h3>
 		Default transition time: <input name="TD" type="number" class="xl" min="0" max="65500"> ms<br>
diff --git a/wled00/set.cpp b/wled00/set.cpp
index 087e9b39f2..9c85c8ca5a 100644
--- a/wled00/set.cpp
+++ b/wled00/set.cpp
@@ -341,7 +341,7 @@ void handleSettingsSet(AsyncWebServerRequest *request, byte subPage)
     gammaCorrectBri = request->hasArg(F("GB"));
     gammaCorrectCol = request->hasArg(F("GC"));
     gammaCorrectVal = request->arg(F("GV")).toFloat();
-    if (gammaCorrectVal <= 1.0f || gammaCorrectVal > 3) {
+    if (gammaCorrectVal < 0.1f || gammaCorrectVal > 3) {
       gammaCorrectVal = 1.0f; // no gamma correction
       gammaCorrectBri = false;
       gammaCorrectCol = false;

From 9d55b186146034c13b0998838a80965642901b22 Mon Sep 17 00:00:00 2001
From: Flo <flo@Mac.lan>
Date: Fri, 12 Dec 2025 19:38:52 +0100
Subject: [PATCH 2/3] Enable inverse gamma correction (gamma < 1.0)

Allow gamma values from 0.1 to 3.0 instead of restricting to > 1.0.
This enables inverse gamma curves for use cases requiring brightened
mid-tones and compressed highlights.

Changes:
- Update backend validation in set.cpp and cfg.cpp to accept 0.1-3.0
- Update HTML form min value from 1 to 0.1

The calcGammaTable() function already supports any gamma value
mathematically, so this just removes an artificial restriction.
---
 wled00/cfg.cpp                | 10 +++++-----
 wled00/data/settings_leds.htm |  2 +-
 wled00/set.cpp                |  2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/wled00/cfg.cpp b/wled00/cfg.cpp
index 47ba152c96..9972205ec1 100644
--- a/wled00/cfg.cpp
+++ b/wled00/cfg.cpp
@@ -508,11 +508,11 @@ bool deserializeConfig(JsonObject doc, bool fromFS) {
   CJSON(gammaCorrectVal, light["gc"]["val"]); // default 2.2
   float light_gc_bri = light["gc"]["bri"];
   float light_gc_col = light["gc"]["col"];
-  if (light_gc_bri > 1.0f) gammaCorrectBri = true;
-  else                     gammaCorrectBri = false;
-  if (light_gc_col > 1.0f) gammaCorrectCol = true;
-  else                     gammaCorrectCol = false;
-  if (gammaCorrectVal <= 1.0f || gammaCorrectVal > 3) {
+  if (light_gc_bri != 1.0f) gammaCorrectBri = true;
+  else                      gammaCorrectBri = false;
+  if (light_gc_col != 1.0f) gammaCorrectCol = true;
+  else                      gammaCorrectCol = false;
+  if (gammaCorrectVal < 0.1f || gammaCorrectVal > 3) {
     gammaCorrectVal = 1.0f; // no gamma correction
     gammaCorrectBri = false;
     gammaCorrectCol = false;
diff --git a/wled00/data/settings_leds.htm b/wled00/data/settings_leds.htm
index 47c4f514d8..f683c964f1 100644
--- a/wled00/data/settings_leds.htm
+++ b/wled00/data/settings_leds.htm
@@ -937,7 +937,7 @@ <h3>Defaults</h3>
 		Apply preset <input name="BP" type="number" class="m" min="0" max="250" required> at boot (0 uses values from above)<br><br>
 		Use Gamma correction for color: <input type="checkbox" name="GC"> (strongly recommended)<br>
 		Use Gamma correction for brightness: <input type="checkbox" name="GB"> (not recommended)<br>
-		Use Gamma value: <input name="GV" type="number" class="m" placeholder="2.8" min="1" max="3" step="0.1" required><br><br>
+		Use Gamma value: <input name="GV" type="number" class="m" placeholder="2.8" min="0.1" max="3" step="0.1" required><br><br>
 		Brightness factor: <input name="BF" type="number" class="m" min="1" max="255" required> %
 		<h3>Transitions</h3>
 		Default transition time: <input name="TD" type="number" class="xl" min="0" max="65500"> ms<br>
diff --git a/wled00/set.cpp b/wled00/set.cpp
index 087e9b39f2..9c85c8ca5a 100644
--- a/wled00/set.cpp
+++ b/wled00/set.cpp
@@ -341,7 +341,7 @@ void handleSettingsSet(AsyncWebServerRequest *request, byte subPage)
     gammaCorrectBri = request->hasArg(F("GB"));
     gammaCorrectCol = request->hasArg(F("GC"));
     gammaCorrectVal = request->arg(F("GV")).toFloat();
-    if (gammaCorrectVal <= 1.0f || gammaCorrectVal > 3) {
+    if (gammaCorrectVal < 0.1f || gammaCorrectVal > 3) {
       gammaCorrectVal = 1.0f; // no gamma correction
       gammaCorrectBri = false;
       gammaCorrectCol = false;

From 6b15f924bee8616689e9e8dca15f7a08195e0ecb Mon Sep 17 00:00:00 2001
From: Damian Schneider <daedae@gmx.ch>
Date: Sun, 8 Feb 2026 17:46:41 +0100
Subject: [PATCH 3/3] adjust placeholder value to new default

---
 wled00/data/settings_leds.htm | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/wled00/data/settings_leds.htm b/wled00/data/settings_leds.htm
index b04e57fe9f..469617f148 100644
--- a/wled00/data/settings_leds.htm
+++ b/wled00/data/settings_leds.htm
@@ -958,7 +958,7 @@ <h3>Defaults</h3>
 		Apply preset <input name="BP" type="number" class="m" min="0" max="250" required> at boot (0 uses values from above)<br><br>
 		Use Gamma correction for color: <input type="checkbox" name="GC"> (strongly recommended)<br>
 		Use Gamma correction for brightness: <input type="checkbox" name="GB"> (not recommended)<br>
-		Use Gamma value: <input name="GV" type="number" class="m" placeholder="2.8" min="0.1" max="3" step="0.1" required><br><br>
+		Use Gamma value: <input name="GV" type="number" class="m" placeholder="2.2" min="0.1" max="3" step="0.1" required><br><br>
 		Brightness factor: <input name="BF" type="number" class="m" min="1" max="255" required> %
 		<h3>Transitions</h3>
 		Default transition time: <input name="TD" type="number" class="xl" min="0" max="65500"> ms<br>