# FramelessHelper

## Usage

Copy *winnativeeventfilter.h* and *winnativeeventfilter.cpp* to your project and use `WinNativeEventFilter::install();` or `WinNativeEventFilter::addFramelessWindow(reinterpret_cast<HWND>(myWidget->winId()));` before any windows (widgets and Qt Quick windows) show up, just like what the example project does.

## Notice

- Any widgets (or Qt Quick elements) in the titlebar area will not be resposible because the mouse events are intercepted. Try if `WinNativeEventFilter::setWindowData()` helps.
- Don't change the window flags (for example, enable the Qt::FramelessWindowHint flag) because it will break the functionality of this code. I'll get rid of the window frame (including the titlebar of course) in Win32 native events.
- All traditional Win32 APIs are replaced by their DPI-aware ones, if there is one.
- Start from Windows 10, normal windows usually have a one pixel width border line, I don't add it because not everyone like it. You can draw one manually if you really need it.
- The frame shadow will get lost if the window is totally transparent. It can't be solved unless you draw the frame shadow manually.
- On Windows 7, if you disabled the Windows Aero, the frame shadow will be disabled as well because it's DWM's resposibility to draw the frame shadow.
- Only top level windows can be frameless. Applying this code to child windows or widgets will result in unexpected behavior.
- The border width (8 if not scaled), border height (8 if not scaled) and titlebar height (30/38 if not scaled) are acquired by Win32 APIs and are the same with other standard windows, and thus you should not modify them.
- You can also copy all the code to `[virtual protected] bool QWidget::nativeEvent(const QByteArray &eventType, void *message, long *result)` or `[virtual protected] bool QWindow::nativeEvent(const QByteArray &eventType, void *message, long *result)`, it's the same with install a native event filter to the application.
- For UNIX platforms, things are much easier. Just use the `startSystemMove` and `startSystemResize` APIs introduced in Qt 5.15.

## References

- <https://github.com/rossy/borderless-window>
- <https://github.com/Bringer-of-Light/Qt-Nice-Frameless-Window>
- <https://github.com/dfct/TrueFramelessWindow>
- <https://github.com/qtdevs/FramelessHelper>
- <https://docs.microsoft.com/en-us/archive/blogs/wpfsdk/custom-window-chrome-in-wpf>

## Special Thanks

Thanks **Lucas** for testing this code in many various conditions.