Flicker-free dimming slider for OLED models (#2109)

* Gamma Init

* Cleanup

* Show flicker-free dimming only on supported models

* Gamma ramp tweaks

* Gamma improvements

* Stronger dimming

* Added OLED model detection

app/Display/DisplayGammaRamp.cs

@@ -0,0 +1,112 @@
+namespace GHelper.Display
+{
+
+    public class DisplayGammaRamp
+    {
+
+        public DisplayGammaRamp(ushort[] red, ushort[] green, ushort[] blue)
+        {
+            if (red?.Length != GammaRamp.DataPoints)
+            {
+                throw new ArgumentOutOfRangeException(nameof(red));
+            }
+
+            if (green?.Length != GammaRamp.DataPoints)
+            {
+                throw new ArgumentOutOfRangeException(nameof(green));
+            }
+
+            if (blue?.Length != GammaRamp.DataPoints)
+            {
+                throw new ArgumentOutOfRangeException(nameof(blue));
+            }
+
+            Red = red;
+            Green = green;
+            Blue = blue;
+        }
+
+        public DisplayGammaRamp(double brightness = 1, double contrast = 1, double gamma = 1)
+            : this(
+                CalculateLUT(brightness, contrast, gamma),
+                CalculateLUT(brightness, contrast, gamma),
+                CalculateLUT(brightness, contrast, gamma)
+            )
+        {
+        }
+
+        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)
+        {
+            brightness = 0.5 + brightness / 2;
+            var result = new ushort[GammaRamp.DataPoints];
+            for (var i = 0; i < result.Length; i++)
+            {
+                result[i] = (ushort)(brightness * ushort.MaxValue * i / (float)(result.Length - 1));
+            }
+            return result;
+        }
+
+        public bool IsOriginal()
+        {
+            int MaxRed = Red[Red.Length - 1];
+            int MaxGreen = Green[Green.Length - 1];
+            int MaxBlue = Blue[Blue.Length - 1];
+            return (Math.Abs((MaxRed + MaxGreen + MaxBlue) / 3 - ushort.MaxValue) < 256);
+        }
+
+        private static ushort[] Brightness(ushort[] data, double brightness)
+        {
+            var result = new ushort[GammaRamp.DataPoints];
+            for (var i = 0; i < result.Length; i++)
+            {
+                if (brightness < 0.5)
+                    result[i] = (ushort)(0.5 * ushort.MaxValue * Math.Pow((float)i/(result.Length - 1),  2 - brightness*2));
+                else
+                    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()
+        {
+            return new GammaRamp(Red, Green, Blue);
+        }
+
+
+    }
+}

app/Display/GammaRamp.cs

@@ -0,0 +1,56 @@
+using System.Runtime.InteropServices;
+
+namespace GHelper.Display
+{
+
+    [StructLayout(LayoutKind.Sequential)]
+    internal struct GammaRamp
+    {
+        public const int DataPoints = 256;
+
+        [MarshalAs(UnmanagedType.ByValArray, SizeConst = DataPoints)]
+        public readonly ushort[] Red;
+        [MarshalAs(UnmanagedType.ByValArray, SizeConst = DataPoints)]
+        public readonly ushort[] Green;
+        [MarshalAs(UnmanagedType.ByValArray, SizeConst = DataPoints)]
+        public readonly ushort[] Blue;
+
+        public GammaRamp(ushort[] red, ushort[] green, ushort[] blue)
+        {
+            if (red == null)
+            {
+                throw new ArgumentNullException(nameof(red));
+            }
+
+            if (green == null)
+            {
+                throw new ArgumentNullException(nameof(green));
+            }
+
+            if (blue == null)
+            {
+                throw new ArgumentNullException(nameof(blue));
+            }
+
+            if (red.Length != DataPoints)
+            {
+                throw new ArgumentOutOfRangeException(nameof(red));
+            }
+
+            if (green.Length != DataPoints)
+            {
+                throw new ArgumentOutOfRangeException(nameof(green));
+            }
+
+            if (blue.Length != DataPoints)
+            {
+                throw new ArgumentOutOfRangeException(nameof(blue));
+            }
+
+            Red = red;
+            Green = green;
+            Blue = blue;
+        }
+    }
+
+}

app/Display/ScreenControl.cs

@@ -1,4 +1,4 @@
-using System.Diagnostics;
+using System.Runtime.InteropServices;
 
 namespace GHelper.Display
 {
@@ -7,6 +7,8 @@ namespace GHelper.Display
 
         public const int MAX_REFRESH = 1000;
 
+        public static DisplayGammaRamp? gammaRamp;
+
         public void AutoScreen(bool force = false)
         {
             if (force || AppConfig.Is("screen_auto"))
@@ -22,6 +24,70 @@ 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)
+        {
+            var bright = Math.Round((float)brightness / 200 + 0.5, 2);
+
+            var screenName = ScreenNative.FindLaptopScreen();
+            if (screenName is null) return;
+
+            try
+            {
+                var handle = ScreenNative.CreateDC(screenName, screenName, null, IntPtr.Zero);
+                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.IsOriginal())
+                {
+                    Logger.WriteLine("Default Gamma");
+                    gammaRamp = new DisplayGammaRamp();
+                }
+
+                var ramp = gammaRamp.AsBrightnessRamp(bright);
+                bool result = ScreenNative.SetDeviceGammaRamp(handle, ref ramp);
+
+                Logger.WriteLine("Brightness " + bright.ToString() + ": " + result);
+
+            } catch (Exception ex)
+            {
+                Logger.WriteLine(ex.ToString());
+            }
+
+            //ScreenBrightness.Set(60 + (int)(40 * bright));
+        }
+
         public void SetScreen(int frequency = -1, int overdrive = -1, int miniled = -1)
         {
             var laptopScreen = ScreenNative.FindLaptopScreen(true);
@@ -71,7 +137,8 @@ namespace GHelper.Display
             if (miniled1 >= 0)
             {
                 miniled = (miniled1 == 1) ? 0 : 1;
-            } else
+            }
+            else
             {
                 switch (miniled2)
                 {

app/Display/ScreenNative.cs

@@ -32,6 +32,16 @@ namespace GHelper.Display
     }
     internal class ScreenNative
     {
+
+        [DllImport("gdi32", CharSet = CharSet.Unicode)]
+        internal static extern IntPtr CreateDC(string driver, string device, string port, IntPtr deviceMode);
+
+        [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
         {
@@ -146,7 +156,7 @@ namespace GHelper.Display
         public const string defaultDevice = @"\\.\DISPLAY1";
 
 
-        private static string? FindInternalName(bool log = false)
+        public static string? FindInternalName(bool log = false)
         {
             try
             {