taskbar.cpp

#include <Windows.h>
#include <stdio.h>
#include <iostream>

void SetTransparent(HWND target_window, bool type)
{
	DWORD exstyle;
	typedef BOOL(WINAPI* MySetLayeredWindowAttributesType)(HWND, COLORREF, BYTE, DWORD);
	static MySetLayeredWindowAttributesType MySetLayeredWindowAttributes = (MySetLayeredWindowAttributesType)
		GetProcAddress(GetModuleHandle(L"user32"), "SetLayeredWindowAttributes");
	exstyle = GetWindowLong(target_window, GWL_EXSTYLE);
	if (!MySetLayeredWindowAttributes || !exstyle)return;
	if (!type)		SetWindowLong(target_window, GWL_EXSTYLE, exstyle & ~WS_EX_LAYERED);
	else {
		SetWindowLong(target_window, GWL_EXSTYLE, exstyle | WS_EX_LAYERED);
		MySetLayeredWindowAttributes(target_window, 0, 0, LWA_ALPHA);
		if (!type)
		{
			InvalidateRect(target_window, NULL, TRUE);
		}
	}
}
void ToggleTaskbar(bool visible)
{
	APPBARDATA abd = { sizeof abd };
	abd.lParam = visible ? ABS_ALWAYSONTOP : ABS_AUTOHIDE;
	SHAppBarMessage(ABM_SETSTATE, &abd);
	//SHAppBarMessage(ABM_WINDOWPOSCHANGED, &abd);
	HWND mainHwnd = FindWindow(L"Shell_traywnd", L"");
	SetTransparent(mainHwnd, !visible);
	//ShowWindow(mainHwnd, visible ? SW_SHOWNA : SW_HIDE);
	//SHAppBarMessage(ABM_WINDOWPOSCHANGED, &abd);

	HWND hwndNext = nullptr;
	HWND hwnd = nullptr;
	do
	{
		hwnd = FindWindowEx(NULL, hwndNext, L"Shell_SecondaryTrayWnd", L"");
		if (hwnd)
		{
			//ShowWindow(hwnd, visible ? SW_SHOWNA : SW_HIDE);
			SetTransparent(hwnd, !visible);
		}
		hwndNext = hwnd;
	} while (hwnd != nullptr);
	SHAppBarMessage(ABM_WINDOWPOSCHANGED, &abd);
}

int main()
{
	ToggleTaskbar(false);
	std::cin.get();
	ToggleTaskbar(true);
}