From 744b304d4b22e1a8a0e67bc38a1d51fa13c8d013 Mon Sep 17 00:00:00 2001
From: Serge <5920850+seerge@users.noreply.github.com>
Date: Sat, 17 Feb 2024 12:42:32 +0100
Subject: [PATCH] Gamma ramp tweaks

---
 app/Display/DisplayGammaRamp.cs | 51 +++++++++++++++++++++++++++------
 app/Display/ScreenControl.cs    | 44 ++++++++++++++++++++++++++--
 app/Display/ScreenNative.cs     |  3 +-
 app/Settings.cs                 |  1 -
 4 files changed, 85 insertions(+), 14 deletions(-)

diff --git a/app/Display/DisplayGammaRamp.cs b/app/Display/DisplayGammaRamp.cs
index 5dea8c19..cdd30a5e 100644
--- a/app/Display/DisplayGammaRamp.cs
+++ b/app/Display/DisplayGammaRamp.cs
@@ -1,4 +1,5 @@
 using System.Diagnostics;
+using System.Reflection.Metadata.Ecma335;
 using System.Runtime.InteropServices;
 
 namespace GHelper.Display
@@ -29,7 +30,7 @@ namespace GHelper.Display
             Blue = blue;
         }
 
-        public DisplayGammaRamp(double brightness = 0.5, double contrast = 0.5, double gamma = 1)
+        public DisplayGammaRamp(double brightness = 1, double contrast = 1, double gamma = 1)
             : this(
                 CalculateLUT(brightness, contrast, gamma),
                 CalculateLUT(brightness, contrast, gamma),
@@ -38,28 +39,60 @@ namespace GHelper.Display
         {
         }
 
+        public DisplayGammaRamp(
+            double redBrightness,
+            double redContrast,
+            double redGamma,
+            double greenBrightness,
+            double greenContrast,
+            double greenGamma,
+            double blueBrightness,
+            double blueContrast,
+            double blueGamma
+        )
+            : this(
+                CalculateLUT(redBrightness, redContrast, redGamma),
+                CalculateLUT(greenBrightness, greenContrast, greenGamma),
+                CalculateLUT(blueBrightness, blueContrast, blueGamma)
+            )
+        {
+        }
 
+        internal DisplayGammaRamp(GammaRamp ramp) :
+            this(ramp.Red, ramp.Green, ramp.Blue)
+        {
+        }
         public ushort[] Blue { get; }
         public ushort[] Green { get; }
         public ushort[] Red { get; }
         private static ushort[] CalculateLUT(double brightness, double contrast, double gamma)
         {
-
-            // Fill the gamma curve
             var result = new ushort[GammaRamp.DataPoints];
-            string bits = "";
-
             for (var i = 0; i < result.Length; i++)
             {
                 result[i] = (ushort)((0.5 + brightness / 2) * ushort.MaxValue * i / (float)(result.Length - 1));
-                bits += result[i].ToString() + " ";
             }
-
-            //Debug.WriteLine(bits);
-
             return result;
         }
 
+        private static ushort[] Brightness(ushort[] data, double brightness)
+        {
+            var result = new ushort[GammaRamp.DataPoints];
+            for (var i = 0; i < result.Length; i++)
+            {
+                result[i] = (ushort)(data[i]*brightness);
+            }
+            return result;
+        }
+
+        internal GammaRamp AsBrightnessRamp(double brightness)
+        {
+            return new GammaRamp(
+                Brightness(Red, brightness),
+                Brightness(Green, brightness),
+                Brightness(Blue, brightness)
+            );
+        }
 
         internal GammaRamp AsRamp()
         {
diff --git a/app/Display/ScreenControl.cs b/app/Display/ScreenControl.cs
index 83fcedc3..eb698ffd 100644
--- a/app/Display/ScreenControl.cs
+++ b/app/Display/ScreenControl.cs
@@ -7,7 +7,7 @@ namespace GHelper.Display
 
         public const int MAX_REFRESH = 1000;
 
-        public static DisplayGammaRamp? gamma;
+        public static DisplayGammaRamp? gammaRamp;
 
         public void AutoScreen(bool force = false)
         {
@@ -24,6 +24,29 @@ namespace GHelper.Display
             }
         }
 
+        public void SaveGamma()
+        {
+            var screenName = ScreenNative.FindLaptopScreen();
+            if (screenName is null) return;
+
+            try
+            {
+                var handle = ScreenNative.CreateDC(screenName, screenName, null, IntPtr.Zero);
+                var gammaRamp = new GammaRamp();
+                if (ScreenNative.GetDeviceGammaRamp(handle, ref gammaRamp))
+                {
+                    var gamma = new DisplayGammaRamp(gammaRamp);
+                    Logger.WriteLine("Gamma R: " + string.Join("-", gamma.Red));
+                    Logger.WriteLine("Gamma G: " + string.Join("-", gamma.Green));
+                    Logger.WriteLine("Gamma B: " + string.Join("-", gamma.Blue));
+                }
+            }
+            catch (Exception ex)
+            {
+                Logger.WriteLine(ex.ToString());
+            }
+        }
+
         public void SetGamma(int brightness = 100, int contrast = 100)
         {
             var bright = (float)(brightness) / 100;
@@ -35,8 +58,23 @@ namespace GHelper.Display
             try
             {
                 var handle = ScreenNative.CreateDC(screenName, screenName, null, IntPtr.Zero);
-                var gammaRamp = new DisplayGammaRamp(bright, bright, 1).AsRamp();
-                ScreenNative.SetDeviceGammaRamp(handle, ref gammaRamp);
+                if (gammaRamp is null)
+                {
+                    var gammaDump = new GammaRamp();
+                    if (ScreenNative.GetDeviceGammaRamp(handle, ref gammaDump))
+                    {
+                        gammaRamp = new DisplayGammaRamp(gammaDump);
+                        Logger.WriteLine("Gamma R: " + string.Join("-", gammaRamp.Red));
+                        Logger.WriteLine("Gamma G: " + string.Join("-", gammaRamp.Green));
+                        Logger.WriteLine("Gamma B: " + string.Join("-", gammaRamp.Blue));
+                    }
+                }
+
+                if (gammaRamp is null) gammaRamp = new DisplayGammaRamp();
+
+                var ramp = gammaRamp.AsBrightnessRamp(bright);
+                ScreenNative.SetDeviceGammaRamp(handle, ref ramp);
+
             } catch (Exception ex)
             {
                 Logger.WriteLine(ex.ToString());
diff --git a/app/Display/ScreenNative.cs b/app/Display/ScreenNative.cs
index 2d7d60f6..0b260fd3 100644
--- a/app/Display/ScreenNative.cs
+++ b/app/Display/ScreenNative.cs
@@ -39,7 +39,8 @@ namespace GHelper.Display
         [DllImport("gdi32")]
         internal static extern bool SetDeviceGammaRamp(IntPtr dcHandle, ref GammaRamp ramp);
 
-
+        [DllImport("gdi32")]
+        internal static extern bool GetDeviceGammaRamp(IntPtr dcHandle, ref GammaRamp ramp);
 
         [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
         public struct DEVMODE
diff --git a/app/Settings.cs b/app/Settings.cs
index 10110925..348a2495 100644
--- a/app/Settings.cs
+++ b/app/Settings.cs
@@ -260,7 +260,6 @@ namespace GHelper
             panelPerformance.Focus();
         }
 
-
         private void SliderGamma_ValueChanged(object? sender, EventArgs e)
         {
             screenControl.SetGamma(sliderGamma.Value);