Add event for viewport limit updates

source/core/inc/tactile/core/event/viewport_event_handler.hpp

@@ -13,6 +13,7 @@ class EventDispatcher;
 
 struct OffsetViewportEvent;
 struct UpdateViewportSizeEvent;
+struct UpdateViewportLimitsEvent;
 struct IncreaseViewportZoomEvent;
 struct DecreaseViewportZoomEvent;
 struct ResetViewportZoomEvent;
@@ -56,6 +57,13 @@ class ViewportEventHandler final
    */
   void on_update_viewport_size(const UpdateViewportSizeEvent& event);
 
+  /**
+   * Updates the limits of a viewport.
+   *
+   * \param event The associated event.
+   */
+  void on_update_viewport_limits(const UpdateViewportLimitsEvent& event);
+
   /**
    * Increases the zoom of a viewport.
    *

source/core/inc/tactile/core/event/viewport_events.hpp

@@ -32,6 +32,21 @@ struct UpdateViewportSizeEvent final
   Float2 new_size;
 };
 
+/**
+ * Event for changing the limits of a viewport in the current document.
+ */
+struct UpdateViewportLimitsEvent final
+{
+  /** The target viewport. */
+  EntityID viewport_entity;
+
+  /** The new minimum position. */
+  Float2 min_pos;
+
+  /** The new maximum position. */
+  Float2 max_pos;
+};
+
 /**
  * Event for increasing the zoom of a viewport in the current document.
  */

source/core/src/tactile/core/event/viewport_event_handler.cpp

@@ -30,6 +30,7 @@ void ViewportEventHandler::install(EventDispatcher& dispatcher)
   // clang-format off
   dispatcher.bind<OffsetViewportEvent, &Self::on_offset_viewport>(this);
   dispatcher.bind<UpdateViewportSizeEvent, &Self::on_update_viewport_size>(this);
+  dispatcher.bind<UpdateViewportLimitsEvent, &Self::on_update_viewport_limits>(this);
   dispatcher.bind<IncreaseViewportZoomEvent, &Self::on_increase_viewport_zoom>(this);
   dispatcher.bind<DecreaseViewportZoomEvent, &Self::on_decrease_viewport_zoom>(this);
   dispatcher.bind<ResetViewportZoomEvent, &Self::on_reset_viewport_zoom>(this);
@@ -75,6 +76,28 @@ void ViewportEventHandler::on_update_viewport_size(
   }
 }
 
+void ViewportEventHandler::on_update_viewport_limits(
+    const UpdateViewportLimitsEvent& event)
+{
+  if (mModel->get_settings().log_verbose_events) {
+    TACTILE_LOG_TRACE(
+        "UpdateViewportLimitsEvent(viewport: {}, min: {}, max: {})",
+        entity_to_string(event.viewport_entity),
+        event.min_pos,
+        event.max_pos);
+  }
+
+  if (auto* document = mModel->get_current_document()) {
+    auto& registry = document->get_registry();
+    auto& limits = registry.get<CViewportLimits>(event.viewport_entity);
+    limits.min_pos = event.min_pos;
+    limits.max_pos = event.max_pos;
+
+    auto& viewport = registry.get<CViewport>(event.viewport_entity);
+    translate_viewport(viewport, Float2 {0, 0}, &limits);
+  }
+}
+
 void ViewportEventHandler::on_increase_viewport_zoom(
     const IncreaseViewportZoomEvent& event)
 {