The API for file dialogs is heavily inspired by Electron's API:
xwin::MessageDesc mdesc;
xwin::showMessageBox(mdesc)
xwin::OpenDialogDesc odesc;
odesc.title = "Open File";
odesc.filters.emplace_back( "Images", { "png", "jpg", "gif" } );
xwin::showOpenDialog(odesc);
xwin::SaveDialogDesc sdesc;
sdesc.title = "Save As";
sdesc.filters.emplace_back( "Images", { "png", "jpg", "gif" } );
xwin::showSaveDialog(sdesc);