using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;//必须引用此项
namespace WindowsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
SetGamma(trackBar1.Value);
}
[DllImport("gdi32.dll")]
public static extern int GetDeviceGammaRamp(IntPtr hDC, ref RAMP lpRamp);
RAMP ramp = new RAMP();
[DllImport("gdi32.dll")]
public static extern int SetDeviceGammaRamp(IntPtr hDC, ref RAMP lpRamp);
[DllImport("user32.dll")]
static extern IntPtr GetDC(IntPtr hWnd);
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public struct RAMP
{
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 256)]
public UInt16[] Red;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 256)]
public UInt16[] Green;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 256)]
public UInt16[] Blue;
}
void SetGamma(int gamma)
{
ramp.Red = new ushort[256];
ramp.Green = new ushort[256];
ramp.Blue = new ushort[256];
for (int i = 1; i < 256; i++)
{
// gamma 必须在3和44之间
ramp.Red[i] = ramp.Green[i] = ramp.Blue[i] = (ushort)(Math.Min(65535, Math.Max(0, Math.Pow((i + 1) / 256.0, gamma * 0.1) * 65535 + 0.5)));
}
SetDeviceGammaRamp(GetDC(IntPtr.Zero), ref ramp);
}
}
}