Изменение яркости экрана

SetBrightness(HDC hDC,int wBrightness)
{
/*
Changes the brightness of the entire screen.
This function may not work properly in some video cards.
 
The wBrightness value should be a number between 0 and 255.
128 = Обычная яркость
выше 128 = ярче
ниже 128 = темнее
If hDC is NULL, SetBrightness automatically load and release
the display device context for you.
*/
BOOL bReturn = FALSE;
HDC hGammaDC = hDC;
//Load the display device context of the entire screen if hDC is NULL.
if (hDC == NULL)
  {
  hGammaDC = GetDC(NULL);
  }
 
if (hGammaDC != NULL)
    {
    WORD GammaArray[3][256];
  for (int iIndex = 0; iIndex < 256; iIndex++)
        {
    int iArrayValue = iIndex * (wBrightness + 128);
    if (iArrayValue > 65535)
      {
      iArrayValue = 65535;
      }
    GammaArray[0][iIndex] =
        GammaArray[1][iIndex] =
        GammaArray[2][iIndex] = (WORD)iArrayValue;
        }
  bReturn = SetDeviceGammaRamp(hGammaDC, GammaArray);
    }
 
if (hDC == NULL)
  {
    ReleaseDC(NULL, hGammaDC);
  }
 
return bReturn;
}
 
void __fastcall TForm1::Button1Click(TObject *Sender)
{
SetBrightness(NULL,64);
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button2Click(TObject *Sender)
{
SetBrightness(NULL,128);
}
//---------------------------------------------------------------------------

//---------------------------------------------------------------------------
 
#include <vcl.h>
#pragma hdrstop
 
#include "Bcp.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma link "sTrackBar"
#pragma link "sSkinManager"
#pragma link "acPNG"
#pragma link "sGauge"
#pragma link "trayicon"
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------
 
 
 
// Code
SetBrightness(HDC hDC,int wBrightness)
{
/*
Changes the brightness of the entire screen.
This function may not work properly in some video cards.
 
The wBrightness value should be a number between 0 and 255.
128 = Обычная яркость
выше 128 = ярче
ниже 128 = темнее
If hDC is NULL, SetBrightness automatically load and release
the display device context for you.
*/
BOOL bReturn = FALSE;
HDC hGammaDC = hDC;
//Load the display device context of the entire screen if hDC is NULL.
if (hDC == NULL)
  {
  hGammaDC = GetDC(NULL);
  }
 
if (hGammaDC != NULL)
        {
        WORD GammaArray[3][256];
  for (int iIndex = 0; iIndex < 256; iIndex++)
                {
    int iArrayValue = iIndex * (wBrightness + 128);
        if (iArrayValue > 65535)
      {
      iArrayValue = 65535;
      }
    GammaArray[0][iIndex] =
                GammaArray[1][iIndex] =
                GammaArray[2][iIndex] = (WORD)iArrayValue;
                }
  bReturn = SetDeviceGammaRamp(hGammaDC, GammaArray);
        }
 
if (hDC == NULL)
  {
        ReleaseDC(NULL, hGammaDC);
  }
 
return bReturn;
}
// Code end
 
 
void __fastcall TForm1::sTrackBar1Change(TObject *Sender)
{
 sGauge1 -> Progress = sTrackBar1 -> Position;
 SetBrightness(NULL,sTrackBar1 -> Position);
}
 
void __fastcall TForm1::N1Click(TObject *Sender)
{
         TrayIcon1 -> Visible = true;
         Form1->TrayIcon1->Minimize();        
}
//---------------------------------------------------------------------------
void __fastcall TForm1::N6Click(TObject *Sender)
{
         TrayIcon1 -> Visible = false;
         Form1->TrayIcon1->Restore();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::N3Click(TObject *Sender)
{
// Help file include
}
//---------------------------------------------------------------------------
void __fastcall TForm1::N4Click(TObject *Sender)
{
 // About form include       
}
 
//---------------------------------------------------------------------------
void __fastcall TForm1::N5Click(TObject *Sender)
{
        Form1->Close();        
}
//---------------------------------------------------------------------------

RegisterHotKey(Form1->Handle,         // Handle окна, которому отправлять сообщения WM_HOTKEY
                             0x00F,                 // УСЛОВНЫЙ идентификатор горячего ключа
                             MOD_FN, // модификаторы
                             VK_F6              // код клавиши
                             );