Show specific frame when updating screen (#4264)

* Updated setFrames in Screen.cpp

Added code to attempt to revert back to the same frame that user was on prior to setFrame reload.

* Space added Screen.cpp

* Update Screen.cpp

Make screen to revert to Frame 0 if the originally displayed frame is no longer there.

* Update Screen.cpp

Inserted boolean holdPosition into setFrames to indicate the requirement to stay on the same frame ( if =true) or else it will switch to new frame .
Only Screen::handleStatusUpdate calls with setFrame(true). ( For Node Updates)
All other types of updates call as before setFrame(), so it will change focus as needed.

* Hold position, even if number of frames increases

* Hold position, if handling an outgoing text message

* Update Screen.cpp

* Reverted chnages related to devicestate.has_rx_text_message

* Reset to master

* CannedMessages only handles routing packets when waiting for ACK
Previously, this was calling Screen::setFrames at unexpected times

* Gather position info about screen frames while regenerating

* Make admin module observable
Notify only when relevant. Currently: only to handle remove_nodenum.

* Optionally specify which frame to focus when setFrames runs

* UIFrameEvent uses enum instead of multiple booleans

* Allow modules to request their own frame to be focussed
This is done internally by calling MeshModule::requestFocus()
Easier this way, insteady of passing the info in the UIFrameEvent:
* Modules don't always know whether they should be focussed until after the UIFrameEvent has been raised, in dramFrame
* Don't have to pass reference to module instance as parameter though several methods

* E-Ink screensaver uses FOCUS_PRESERVE
Previously, it had its own basic implementation of this.

* Spelling: regional variant

* trunk

* Fix HAS_SCREEN guarding

* More HAS_SCREEN guarding

---------

Co-authored-by: BIST <77391720+slash-bit@users.noreply.github.com>
Co-authored-by: Ben Meadors <benmmeadors@gmail.com>
Co-authored-by: slash-bit <v-b2@live.com>

src/mesh/MeshModule.h

@@ -35,10 +35,16 @@ enum class AdminMessageHandleResult {
 /*
  * This struct is used by Screen to figure out whether screen frame should be updated.
  */
-typedef struct _UIFrameEvent {
-    bool frameChanged;
-    bool needRedraw;
-} UIFrameEvent;
+struct UIFrameEvent {
+    // What do we actually want to happen?
+    enum Action {
+        REDRAW_ONLY,                    // Don't change which frames are show, just redraw, asap
+        REGENERATE_FRAMESET,            // Regenerate (change? add? remove?) screen frames, honoring requestFocus()
+        REGENERATE_FRAMESET_BACKGROUND, // Regenerate screen frames, attempting to remain on the same frame throughout
+    } action = REDRAW_ONLY;
+
+    // We might want to pass additional data inside this struct at some point
+};
 
 /** A baseclass for any mesh "module".
  *
@@ -73,6 +79,7 @@ class MeshModule
                                                                     meshtastic_AdminMessage *response);
 #if HAS_SCREEN
     virtual void drawFrame(OLEDDisplay *display, OLEDDisplayUiState *state, int16_t x, int16_t y) { return; }
+    virtual bool isRequestingFocus(); // Checked by screen, when regenerating frameset
 #endif
   protected:
     const char *name;
@@ -176,6 +183,19 @@ class MeshModule
         return AdminMessageHandleResult::NOT_HANDLED;
     };
 
+#if HAS_SCREEN
+    /** Request that our module's screen frame be focused when Screen::setFrames runs
+     * Only considered if Screen::setFrames is triggered via a UIFrameEvent
+     *
+     * Having this as a separate call, instead of part of the UIFrameEvent, allows the module to delay decision
+     * until drawFrame() is called. This required less restructuring.
+     */
+    bool _requestingFocus = false;
+    void requestFocus() { _requestingFocus = true; }
+#else
+    void requestFocus(){}; // No-op
+#endif
+
   private:
     /**
      * If any of the current chain of modules has already sent a reply, it will be here.  This is useful to allow