ui: a slide-over panel over the plot's right edge, with its probe

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/ui_app.hpp

@@ -117,6 +117,19 @@ struct SourcePanelPage {
   GtkWidget* content = nullptr;
 };
 
+/// The slide-over panel's widgets and state (src/ui_slideover.cpp). `page` is the open page's id, empty when closed.
+struct SlideOver {
+  GtkWidget* overlay = nullptr;       ///< the GtkOverlay around the plot (main-window.ui `plot_overlay`)
+  GtkWidget* revealer = nullptr;      ///< the one overlay child; halign END, valign FILL, 360 px
+  GtkWidget* title = nullptr;         ///< GtkLabel in the panel header
+  GtkWidget* stack = nullptr;         ///< GtkStack: one scroller per page
+  GtkWidget* source_switch = nullptr; ///< AdwToggleGroup, shown on a source page when there are >= 2
+  std::vector<std::string> source_pages;
+  std::string page;
+  bool syncing = false;               ///< true while we write the toggle group ourselves
+};
+constexpr int kSlideOverWidth = 360;
+
 struct App {
   ScopeModel* model = nullptr;
   Acquisition* acq = nullptr;
@@ -124,6 +137,9 @@ struct App {
 
   GtkWidget* window = nullptr;
   GtkWidget* plot_box = nullptr;
+  /// The `GtkOverlay` around `plot_box` (`main-window.ui`), which the slide-over panel is a child of.
+  GtkWidget* plot_overlay = nullptr;
+  SlideOver slideover;
   /// The one GL area, drawing the `RowSet`'s figure: every row is a row of that
   /// figure, so there is one widget, one context and one `::render` whatever the row
   /// count is.
@@ -1872,6 +1888,19 @@ gboolean stats_probe_report(gpointer user);
 gboolean stats_probe(gpointer user);
 gboolean side_tab_probe_report(gpointer user);
 gboolean side_tab_probe(gpointer user);
+/// The slide-over panel (`src/ui_slideover.cpp`): one panel at a time over the plot's right edge, a page
+/// per setup surface, each page in a scroller of its own.
+void build_slideover(App& app);  // once, after the plot_overlay exists
+bool slideover_add_page(App& app, const std::string& id, const std::string& title, GtkWidget* content);
+bool slideover_has_page(const App& app, const std::string& id);
+bool slideover_open(App& app, const std::string& id);  // false when the id is unknown
+void slideover_close(App& app);
+bool slideover_toggle(App& app, const std::string& id);  // open if closed or on another page, else close
+const std::string& slideover_page(const App& app);       // "" when closed
+bool slideover_escape(App& app);                         // closes if open; true when it did
+/// x, y in the overlay's coordinates; closes unless the point is inside the panel; true when it closed.
+bool slideover_click_away(App& app, double x, double y);
+gboolean slideover_probe(gpointer user);  // UDPSCOPE_PROBE_SLIDEOVER_MS
 gboolean source_kinds_probe_report(gpointer user);
 gboolean source_kinds_probe(gpointer user);
 /// MCC E-1608 end to end against `tools/mock_e1608.py`: the stream, the calibration, the panels and