Transparent button WinAPI C++ - c++

Question

I have a simple window, my main window contains WS_EX_LAYERED flag. I can change opacity of main window but when I try to change opacity of children window I'll get some problem. It's not visible. Maybe I should use another flag in CreateWindowEx(..) or use post-fix A or W? I just need visible main window with 100 percentage of opacity and the button, which can change opacity.
#include <windows.h>
LPCWSTR g_szClassName = L"myWindowClass";
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch (msg)
{
case WM_CLOSE:
DestroyWindow(hwnd);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, msg, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX wc;
HWND hwnd, btn;
MSG Msg;
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wc.lpszMenuName = NULL;
wc.lpszClassName = g_szClassName;
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
if (!RegisterClassEx(&wc))
{
MessageBox(NULL, L"Window Registration Failed!", L"Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
hwnd = CreateWindowEx(
WS_EX_LAYERED,
g_szClassName,
L"The title of my window",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT, 600, 600,
NULL, NULL, hInstance, NULL);
btn = CreateWindowEx(
WS_EX_LAYERED,
L"BUTTON",
L"TEXT",
WS_TABSTOP | WS_VISIBLE | WS_CHILD | BS_DEFPUSHBUTTON,
0,
0,
100,
100,
hwnd,
(HMENU)BN_CLICKED,
(HINSTANCE)GetWindowLongPtr(hwnd, GWLP_HINSTANCE),
NULL);
SetLayeredWindowAttributes(hwnd, 0, 255, LWA_ALPHA);
SetLayeredWindowAttributes(btn, 0, 50, LWA_ALPHA);
if (hwnd == NULL)
{
MessageBox(NULL, L"Window Creation Failed!", L"Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
ShowWindow(hwnd, nCmdShow);
ShowWindow(btn, nCmdShow);
UpdateWindow(hwnd);
while (GetMessage(&Msg, NULL, 0, 0) > 0)
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
return Msg.wParam;
}

Answer 1

First you need to add a manifest file in the application directory to specify Windows 8 compatibility.
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
<compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
<application>
<!--The ID below indicates app support for Windows 8 -->
<supportedOS Id="{4a2f28e3-53b9-4441-ba9c-d69d4a4a6e38}"/>
</application>
</compatibility>
<dependency>
<dependentAssembly>
<assemblyIdentity
type="win32"
name="Microsoft.Windows.Common-Controls"
version="6.0.0.0"
processorArchitecture="*"
publicKeyToken="6595b64144ccf1df"
language="*"
/>
</dependentAssembly>
</dependency>
</assembly>
Then specify the use of the manifest file. If you are using VS, you can set it in Properties->Manifest Tool->Input and Out->Additional Manifest Files.
Finally rebuild the project,output: