Bejeweled-2021/CGammaRamp.cpp at master · GY-code/Bejeweled-2021 · GitHub

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#include <windows.h>
#include "CGammaRamp.h"


/*
CGammaRamp class

Encapsulates the Gamma Ramp API and changes the brightness of
the entire screen.

Written by Nir Sofer.
http://www.nirsoft.net


*/

CGammaRamp::CGammaRamp()
{
    //Initialize all variables.
    hGDI32 = NULL;
    hScreenDC = NULL;
    pGetDeviceGammaRamp = NULL;
    pSetDeviceGammaRamp = NULL;
}

CGammaRamp::~CGammaRamp()
{
    FreeLibrary();
}


BOOL CGammaRamp::LoadLibrary()
{
    BOOL bReturn = FALSE;

    FreeLibrary();
    //Load the GDI library.
    char *CStr = "gdi32.dll";

    size_t len = strlen(CStr) + 1;

    size_t converted = 0;

    wchar_t *WStr;

    WStr=(wchar_t*)malloc(len*sizeof(wchar_t));
    mbstowcs_s(&converted, WStr, len, CStr, _TRUNCATE);

    hGDI32 = ::LoadLibrary(WStr);
    if (hGDI32 != NULL)
    {
        //Get the addresses of GetDeviceGammaRamp and SetDeviceGammaRamp API functions.
        pGetDeviceGammaRamp =
            (Type_SetDeviceGammaRamp)GetProcAddress(hGDI32, "GetDeviceGammaRamp");

        pSetDeviceGammaRamp =
            (Type_SetDeviceGammaRamp)GetProcAddress(hGDI32, "SetDeviceGammaRamp");

        //Return TRUE only if these functions exist.
        if (pGetDeviceGammaRamp == NULL || pSetDeviceGammaRamp == NULL)
            FreeLibrary();
        else
            bReturn = TRUE;
    }

    return bReturn;
}


void CGammaRamp::FreeLibrary()
{
    //Free the GDI library.
    if (hGDI32 != NULL)
    {
        ::FreeLibrary(hGDI32);
        hGDI32 = NULL;
    }
}


BOOL CGammaRamp::LoadLibraryIfNeeded()
{
    BOOL bReturn = FALSE;

    if (hGDI32 == NULL)
        LoadLibrary();

    if (pGetDeviceGammaRamp != NULL && pSetDeviceGammaRamp != NULL)
        bReturn = TRUE;

    return bReturn;
}


BOOL CGammaRamp::SetDeviceGammaRamp(HDC hDC, LPVOID lpRamp)
{
    //Call to SetDeviceGammaRamp only if this function is successfully loaded.
    if (LoadLibraryIfNeeded())
    {
        return pSetDeviceGammaRamp(hDC, lpRamp);
    }
    else
        return FALSE;
}


BOOL CGammaRamp::GetDeviceGammaRamp(HDC hDC, LPVOID lpRamp)
{
    //Call to GetDeviceGammaRamp only if this function is successfully loaded.
    if (LoadLibraryIfNeeded())
    {
        return pGetDeviceGammaRamp(hDC, lpRamp);
    }
    else
        return FALSE;

}


BOOL CGammaRamp::SetBrightness(HDC hDC, WORD 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 = Regular brightness
    above 128 = brighter
    below 128 = darker

    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)
    {
        //Generate the 256-colors array for the specified wBrightness value.
        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;

        }

        //Set the GammaArray values into the display device context.
        bReturn = SetDeviceGammaRamp(hGammaDC, GammaArray);
    }

    if (hDC == NULL)
        ReleaseDC(NULL, hGammaDC);

    return bReturn;
}