+
+ // Find out how many cameras we have in the existing frames;
+ // if none, we start with two cameras.
+ num_cameras = 2;
+ {
+ lock_guard<mutex> lock(frame_mu);
+ for (size_t stream_idx = 2; stream_idx < MAX_STREAMS; ++stream_idx) {
+ if (!frames[stream_idx].empty()) {
+ num_cameras = stream_idx + 1;
+ }
+ }
+ }
+ change_num_cameras();
+
+ if (!global_flags.tally_url.empty()) {
+ start_tally();
+ }
+}
+
+void MainWindow::change_num_cameras()
+{
+ assert(num_cameras >= displays.size()); // We only add, never remove.
+
+ // Make new display rows.
+ unsigned display_rows = (num_cameras + 1) / 2;
+ ui->video_displays->setStretch(1, display_rows);
+ for (unsigned i = displays.size(); i < num_cameras; ++i) {
+ QFrame *frame = new QFrame(this);
+ frame->setAutoFillBackground(true);
+
+ QLayout *layout = new QGridLayout(frame);
+ frame->setLayout(layout);
+ layout->setContentsMargins(3, 3, 3, 3);
+
+ JPEGFrameView *display = new JPEGFrameView(frame);
+ display->setAutoFillBackground(true);
+ layout->addWidget(display);
+
+ ui->input_displays->addWidget(frame, i / 2, i % 2);
+ display->set_overlay(to_string(i + 1));
+
+ QPushButton *preview_btn = new QPushButton(this);
+ preview_btn->setMaximumSize(20, 17);
+ preview_btn->setText(QString::fromStdString(to_string(i + 1)));
+ ui->preview_layout->addWidget(preview_btn);
+
+ displays.emplace_back(FrameAndDisplay{ frame, display, preview_btn });
+
+ connect(display, &JPEGFrameView::clicked, preview_btn, &QPushButton::click);
+ QShortcut *shortcut = new QShortcut(QKeySequence(Qt::Key_1 + i), this);
+ connect(shortcut, &QShortcut::activated, preview_btn, &QPushButton::click);
+
+ connect(preview_btn, &QPushButton::clicked, [this, i]{ preview_angle_clicked(i); });
+ }
+
+ cliplist_clips->change_num_cameras(num_cameras);
+ playlist_clips->change_num_cameras(num_cameras);
+
+ QMetaObject::invokeMethod(this, "relayout", Qt::QueuedConnection);