bool QWindowsMouseHandler::translateMouseWheelEvent(QWindow *window, HWND,
MSG msg, LRESULT *)
{
const Qt::MouseButtons buttons = keyStateToMouseButtons((int)msg.wParam);
const Qt::KeyboardModifiers mods = keyStateToModifiers((int)msg.wParam);
int delta;
if (msg.message == WM_MOUSEWHEEL || msg.message == WM_MOUSEHWHEEL)
delta = (short) HIWORD (msg.wParam);
else
delta = (int) msg.wParam;
Qt::Orientation orientation = (msg.message == WM_MOUSEHWHEEL
|| (buttons & Qt::AltModifier)) ?
Qt::Horizontal : Qt::Vertical;
// according to the MSDN documentation on WM_MOUSEHWHEEL:
// a positive value indicates that the wheel was rotated to the right;
// a negative value indicates that the wheel was rotated to the left.
// Qt defines this value as the exact opposite, so we have to flip the value!
if (msg.message == WM_MOUSEHWHEEL)
delta = -delta;
// Redirect wheel event to one of the following, in order of preference:
// 1) The window under mouse
// 2) The window receiving the event
// If a window is blocked by modality, it can't get the event.
const QPoint globalPos(GET_X_LPARAM(msg.lParam), GET_Y_LPARAM(msg.lParam));
QWindow *receiver = QWindowsScreen::windowAt(globalPos);
bool handleEvent = true;
if (!isValidWheelReceiver(receiver)) {
receiver = window;
if (!isValidWheelReceiver(receiver))
handleEvent = false;
}
if (handleEvent) {
QWindowSystemInterface::handleWheelEvent(receiver,
QWindowsGeometryHint::mapFromGlobal(receiver, globalPos),
globalPos,
delta, orientation, mods);
}
return true;
}
static void redirectWheelEvent(QWindow *window, const QPoint &globalPos, int delta,
Qt::Orientation orientation, Qt::KeyboardModifiers mods)
{
// If a window is blocked by modality, it can't get the event.
if (isValidWheelReceiver(window)) {
QWindowSystemInterface::handleWheelEvent(window,
QWindowsGeometryHint::mapFromGlobal(window, globalPos),
globalPos, delta, orientation, mods);
}
}