Winapi detect button hovering - c++

Question

I've got a C++ project in which I'm using the Winapi to develop a window with a button and I want to change the text of the button when it's being hovered. For example, changing "Click me" to "Click me NOW!", when hovered. I've tried searching but I've not found any good ways to do this.
I noticed that when user hovers, the WM_NOTIFY message is received, but I don't know how to ensure that it has been called by the mouse hover. I've found that I can use TrackMouseEvent to detect hovering, but it's limited to a period of time and I want to execute an action every time the user hovers the button.
Here is how I create a button:
HWND Button = CreateWindow("BUTTON", "Click me",
WS_VISIBLE | WS_CHILD | BS_DEFPUSHBUTTON | BS_NOTIFY,
20, 240, 120, 20,
hwnd, (HMENU)101, NULL, NULL);
And this my window procedure:
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch (msg)
{
case WM_NOTIFY:
{
//??? Here is where I get a message everytime I hover the button, But I don't know any proper way to see if it has been executed by the button.
}
case WM_CREATE: //On Window Create
{
//...
}
case WM_COMMAND: //Command execution
{
//...
break;
}
case WM_DESTROY: //Form Destroyed
{
PostQuitMessage(0);
break;
}
}
return DefWindowProc(hwnd, msg, wParam, lParam);
}

Answer 1

Assuming you're using the common controls there is the BCN_HOTITEMCHANGE notification code for the WM_NOTIFY message. The message includes the NMBCHOTITEM structure, which includes information for whether the mouse is entering or leaving the hover area.
Here's an example:
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch(msg)
{
case WM_NOTIFY:
{
LPNMHDR header = *reinterpret_cast<LPNMHDR>(lParam);
switch (header->code)
{
case BCN_HOTITEMCHANGE:
{
NMBCHOTITEM* hot_item = reinterpret_cast<NMBCHOTITEM*>(lParam);
// Handle to the button
HWND button_handle = header->hwndFrom;
// ID of the button, if you're using resources
UINT_PTR button_id = header->idFrom;
// You can check if the mouse is entering or leaving the hover area
bool entering = hot_item->dwFlags & HICF_ENTERING;
return 0;
}
}
return 0;
}
}
return DefWindowProcW(hwnd, msg, wParam, lParam);
}

Answer 2

You can check the code of the WM_NOTIFY message to see if it is a NM_HOVER message.
switch(msg)
{
case WM_NOTIFY:
if(((LPNMHDR)lParam)->code == NM_HOVER)
{
// Process the hover message
}
else if (...) // any other WM_NOTIFY messages you care about
{}
}

Answer 3

You can use simply SFML to do this.
Code:
RectangleShape button;
button.setPosition(Vector2f(50, 50));
button.setSize(Vector2f(100, 40));
button.setFillColor(Color::Green);
if(button.getGlobalBounds().contains(static_cast<Vector2f>(Mouse::getPosition(/*your
window name*/window)
{
button.setFillColor(Color::Red);
}