How to adjust window border size - c++

Question

I have a window, which I want it to behave like a toggle button. Once clicked it will add 4px border and clicking after will make the border disappear. I figured how to make the window behave like a toggle button using BS_PUSHLIKE and Button_SetCheck() but can't seem to figure out how to adjust the border size for this window.
Thanks to all who take their time to help

Answer 1

Maybe you can use MoveWindow to resize the window, and then draw the border yourself, like this,
Draw a borderless window first:
HWND hWnd = CreateWindowW(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
100, 100, 800, 600, nullptr, nullptr, hInstance, nullptr);
LONG lStyle = GetWindowLong(hWnd, GWL_STYLE);
lStyle &= ~(WS_CAPTION | WS_THICKFRAME | WS_MINIMIZEBOX | WS_MAXIMIZEBOX | WS_SYSMENU);
SetWindowLong(hWnd, GWL_STYLE, lStyle);
Then handle the window border in the WM_LBUTTONDOWN message:
int num = 0;
case WM_LBUTTONDOWN:
{
RECT rcWind;
HDC dc = GetDC(hWnd);
GetWindowRect(hWnd, &rcWind);
if (num >= 0)
{
num--;
RECT rcClient;
MoveWindow(hWnd, rcWind.left - 4, rcWind.top - 4, 8 + rcWind.right - rcWind.left, 8 + rcWind.bottom - rcWind.top, TRUE);
GetClientRect(hWnd, &rcClient);
HPEN hPen = CreatePen(PS_SOLID, 4, RGB(255, 128, 1));
HGDIOBJ hOldPen = SelectObject(dc, hPen);
Rectangle(dc, rcClient.left, rcClient.top, rcClient.right, rcClient.bottom);
DeleteObject(hPen);
}
else if (num < 0)
{
MoveWindow(hWnd, rcWind.left + 4, rcWind.top + 4, rcWind.right - rcWind.left - 8, rcWind.bottom - rcWind.top - 8, TRUE);
num++;
}
}
break;