Transculent Blur Behind

Transculent.h

#pragma once

#include <Windows.h>

const DWORD WCA_ACCENT_POLICY = 19;

enum ACCENT_STATE
{
	ACCENT_DISABLED = 0,
  	ACCENT_ENABLE_GRADIENT = 1,
  	ACCENT_ENABLE_TRANSPARENTGRADIENT = 2,
  	ACCENT_ENABLE_BLURBEHIND = 3,
  	ACCENT_INVALID_STATE = 4,
	_ACCENT_STATE_SIZE = 0xFFFFFFFF
};

struct ACCENTPOLICY
{
	ACCENT_STATE nAccentState;
	DWORD nFlags;
	DWORD nColor;
	DWORD nAnimationId;
};

struct WINCOMPATTRDATA
{
	DWORD nAttribute;
	PVOID pData;
	ULONG ulDataSize;
};

void BlurBehind(HWND hWnd, BOOL enable)
{
	// Dynamically call the SetWindowCompositionAttribute(); function from user32.dll
	const HINSTANCE hModule = LoadLibrary(L"user32.dll");
	typedef BOOL(WINAPI *pSetWindowCompositionAttribute)(HWND, WINCOMPATTRDATA*);
	const pSetWindowCompositionAttribute SetWindowCompositionAttribute = (pSetWindowCompositionAttribute)GetProcAddress(hModule, "SetWindowCompositionAttribute");
	// Do the blur
	if (hModule)
	{
		// if blur enabled
		if (enable)
		{
			if (SetWindowCompositionAttribute)
			{
				ACCENTPOLICY policy = { ACCENT_ENABLE_BLURBEHIND, 0, 0, 0 }; // Set the accent policy data
				WINCOMPATTRDATA dataAttr = { WCA_ACCENT_POLICY, &policy, sizeof(ACCENTPOLICY) }; // then we can put it in to 
				SetWindowCompositionAttribute(hWnd, &dataAttr);
			}
			else
			{
				MessageBox(hWnd, L"Can't apply blur", L"Error!", MB_ICONERROR | MB_OK);
			}
		}
		FreeLibrary(hModule);
	}
	else
	{
		MessageBox(hWnd, L"Can't apply blur", L"Error!", MB_ICONERROR | MB_OK);
	}
	
}