InkHUD refactoring (#6216)

* chore: todo.txt
* chore: comments
* fix: no fast refresh on VME290
Reverts a line of code which was accidentally committed
* refactor: god class
Divide the behavior from the old WindowManager class into several subclasses which each have a clear role.
* refactor: cppcheck medium warnings
Enough to pass github CI for now
* refactor: updateType selection
* refactor: don't use a setter for the shared AppletFonts
* fix: update prioritization
forceUpdate calls weren't being prioritized
* refactor: remove unhelpful logging
getTimeString is used for parsing our own time, but also the timestamps of messages. The "one time only" log printing will likely fire in unhelpful situations.
* fix: " "
* refactor: get rid of types.h file for enums
* Keep that sneaky todo file out of commits

src/graphics/niche/InkHUD/Applets/Bases/Map/MapApplet.cpp

@@ -6,8 +6,6 @@ using namespace NicheGraphics;
 
 void InkHUD::MapApplet::onRender()
 {
-    setFont(fontSmall);
-
     // Abort if no markers to render
     if (!enoughMarkers()) {
         printAt(X(0.5), Y(0.5) - (getFont().lineHeight() / 2), "Node positions", CENTER, MIDDLE);
@@ -27,6 +25,7 @@ void InkHUD::MapApplet::onRender()
     // Set the region shown on the map
     // - default: fit all nodes, plus padding
     // - maybe overriden by derived applet
+    // - getMapSize *sets* passed parameters (C-style)
     getMapSize(&widthMeters, &heightMeters);
 
     // Set the metersToPx conversion value
@@ -71,7 +70,7 @@ void InkHUD::MapApplet::getMapCenter(float *lat, float *lng)
     // - uses tan to find angles for lat / long degrees
     //   - longitude: triangle formed by x and y (on plane of the equator)
     //   - latitude: triangle formed by z (north south),
-    //     and the line along plane of equator which stetches from earth's axis to where point xyz intersects planet's surface
+    //     and the line along plane of equator which stretches from earth's axis to where point xyz intersects planet's surface
 
     // Working totals, averaged after nodeDB processed
     uint32_t positionCount = 0;
@@ -134,7 +133,7 @@ void InkHUD::MapApplet::getMapCenter(float *lat, float *lng)
 
     *lng = atan2(yAvg, xAvg) * RAD_TO_DEG;
 
-    // Latitude from cartesian cooods
+    // Latitude from cartesian coords
     // (Angle from 3D coords describing a point on the globe's surface)
     // As latitude increases, distance from the Earth's north-south axis out to our surface point decreases.
     // Means we need to first find the hypotenuse which becomes base of our triangle in the second step
@@ -191,8 +190,8 @@ void InkHUD::MapApplet::getMapCenter(float *lat, float *lng)
 
         // Longitude is trickier
         float lng = node->position.longitude_i * 1e-7;
-        float degEastward = fmod(((lng - lngCenter) + 360), 360);      // Degrees travelled east from lngCenter to reach node
-        float degWestward = abs(fmod(((lng - lngCenter) - 360), 360)); // Degrees travelled west from lngCenter to reach node
+        float degEastward = fmod(((lng - lngCenter) + 360), 360);      // Degrees traveled east from lngCenter to reach node
+        float degWestward = abs(fmod(((lng - lngCenter) - 360), 360)); // Degrees traveled west from lngCenter to reach node
         if (degEastward < degWestward)
             easternmost = max(easternmost, lngCenter + degEastward);
         else
@@ -258,7 +257,7 @@ void InkHUD::MapApplet::drawLabeledMarker(meshtastic_NodeInfoLite *node)
     // Find x and y position based on node's position in nodeDB
     assert(nodeDB->hasValidPosition(node));
     Marker m = calculateMarker(node->position.latitude_i * 1e-7,  // Lat, converted from Meshtastic's internal int32 style
-                               node->position.longitude_i * 1e-7, // Long, convered from Meshtastic's internal int32 style
+                               node->position.longitude_i * 1e-7, // Long, converted from Meshtastic's internal int32 style
                                node->has_hops_away,               // Is the hopsAway number valid
                                node->hops_away                    // Hops away
     );
@@ -288,7 +287,7 @@ void InkHUD::MapApplet::drawLabeledMarker(meshtastic_NodeInfoLite *node)
     bool unknownHops = !node->has_hops_away && !isOurNode;
 
     // We will draw a left or right hand variant, to place text towards screen center
-    // Hopfully avoid text spilling off screen
+    // Hopefully avoid text spilling off screen
     // Most values are the same, regardless of left-right handedness
 
     // Pick emblem style
@@ -388,7 +387,7 @@ void InkHUD::MapApplet::calculateAllMarkers()
         // Calculate marker and store it
         markers.push_back(
             calculateMarker(node->position.latitude_i * 1e-7,  // Lat, converted from Meshtastic's internal int32 style
-                            node->position.longitude_i * 1e-7, // Long, convered from Meshtastic's internal int32 style
+                            node->position.longitude_i * 1e-7, // Long, converted from Meshtastic's internal int32 style
                             node->has_hops_away,               // Is the hopsAway number valid
                             node->hops_away                    // Hops away
                             ));

src/graphics/niche/InkHUD/Applets/Bases/Map/MapApplet.h

@@ -38,13 +38,12 @@ class MapApplet : public Applet
     void drawLabeledMarker(meshtastic_NodeInfoLite *node); // Highlight a specific marker
 
   private:
-    // Position of markers to be drawn, relative to map center
-    // HopsAway info used to determine marker size
+    // Position and size of a marker to be drawn
     struct Marker {
-        float eastMeters = 0;  // Meters east of mapCenter. Negative if west.
-        float northMeters = 0; // Meters north of mapCenter. Negative if south.
+        float eastMeters = 0;  // Meters east of map center. Negative if west.
+        float northMeters = 0; // Meters north of map center. Negative if south.
         bool hasHopsAway = false;
-        uint8_t hopsAway = 0;
+        uint8_t hopsAway = 0; // Determines marker size
     };
 
     Marker calculateMarker(float lat, float lng, bool hasHopsAway, uint8_t hopsAway);

src/graphics/niche/InkHUD/Applets/Bases/NodeList/NodeListApplet.cpp

@@ -12,7 +12,7 @@ using namespace NicheGraphics;
 InkHUD::NodeListApplet::NodeListApplet(const char *name) : MeshModule(name)
 {
     // We only need to be promiscuous in order to hear NodeInfo, apparently. See NodeInfoModule
-    // For all other packets, we manually reimplement isPromiscuous=false in wantPacket
+    // For all other packets, we manually act as if isPromiscuous=false, in wantPacket
     MeshModule::isPromiscuous = true;
 }
 
@@ -25,17 +25,17 @@ bool InkHUD::NodeListApplet::wantPacket(const meshtastic_MeshPacket *p)
            && (isToUs(p) || isBroadcast(p->to) ||                      // Either: intended for us,
                p->decoded.portnum == meshtastic_PortNum_NODEINFO_APP); // or nodeinfo
 
-    // Note: special handling of NodeInfo is to match NodeInfoModule
     // To match the behavior seen in the client apps:
     // - NodeInfoModule's ProtoBufModule base is "promiscuous"
     // - All other activity is *not* promiscuous
-    // To achieve this, our MeshModule *is* promiscious, and we're manually reimplementing non-promiscuous behavior here,
+
+    // To achieve this, our MeshModule *is* promiscuous, and we're manually reimplementing non-promiscuous behavior here,
     // to match the code in MeshModule::callModules
 }
 
 // MeshModule packets arrive here
 // Extract the info and pass it to the derived applet
-// Derived applet will store the CardInfo and perform any required sorting of the CardInfo collection
+// Derived applet will store the CardInfo, and perform any required sorting of the CardInfo collection
 // Derived applet might also need to keep other tallies (active nodes count?)
 ProcessMessage InkHUD::NodeListApplet::handleReceived(const meshtastic_MeshPacket &mp)
 {
@@ -76,8 +76,8 @@ ProcessMessage InkHUD::NodeListApplet::handleReceived(const meshtastic_MeshPacke
     return ProcessMessage::CONTINUE; // Let others look at this message also if they want
 }
 
-// Maximum number of cards we may ever need to render, in our tallest layout config
-// May be slightly in excess of the true value: header not accounted for
+// Calculate maximum number of cards we may ever need to render, in our tallest layout config
+// Number might be slightly in excess of the true value: applet header text not accounted for
 uint8_t InkHUD::NodeListApplet::maxCards()
 {
     // Cache result. Shouldn't change during execution
@@ -87,7 +87,7 @@ uint8_t InkHUD::NodeListApplet::maxCards()
         const uint16_t height = Tile::maxDisplayDimension();
 
         // Use a loop instead of arithmetic, because it's easier for my brain to follow
-        // Add cards one by one, until the latest card (without margin) extends below screen
+        // Add cards one by one, until the latest card extends below screen
 
         uint16_t y = cardH; // First card: no margin above
         cards = 1;
@@ -102,7 +102,7 @@ uint8_t InkHUD::NodeListApplet::maxCards()
     return cards;
 }
 
-// Draw using info which derived applet placed into NodeListApplet::cards for us
+// Draw, using info which derived applet placed into NodeListApplet::cards for us
 void InkHUD::NodeListApplet::onRender()
 {
 
@@ -120,9 +120,6 @@ void InkHUD::NodeListApplet::onRender()
     // Draw the main node list
     // ========================
 
-    // const uint8_t cardMarginH = fontSmall.lineHeight() / 2; // Gap between cards
-    // const uint16_t cardH = fontLarge.lineHeight() + fontSmall.lineHeight() + cardMarginH;
-
     // Imaginary vertical line dividing left-side and right-side info
     // Long-name will crop here
     const uint16_t dividerX = (width() - 1) - getTextWidth("X Hops");
@@ -215,9 +212,8 @@ void InkHUD::NodeListApplet::onRender()
 
         // Once we've run out of screen, stop drawing cards
         // Depending on tiles / rotation, this may be before we hit maxCards
-        if (cardTopY > height()) {
+        if (cardTopY > height())
             break;
-        }
     }
 }
 
@@ -246,20 +242,20 @@ void InkHUD::NodeListApplet::drawSignalIndicator(int16_t x, int16_t y, uint16_t
 
     constexpr float paddingW = 0.1; // Either side
     constexpr float paddingH = 0.1; // Above and below
-    constexpr float gutterX = 0.1;  // Between bars
+    constexpr float gutterW = 0.1;  // Between bars
 
-    constexpr float barHRel[] = {0.3, 0.5, 0.7, 1.0}; // Heights of the signal bars, relative to the talleest
+    constexpr float barHRel[] = {0.3, 0.5, 0.7, 1.0}; // Heights of the signal bars, relative to the tallest
     constexpr uint8_t barCount = 4; // How many bars we draw. Reference only: changing value won't change the count.
 
     // Dynamically calculate the width of the bars, and height of the rightmost, relative to other dimensions
-    float barW = (1.0 - (paddingW + ((barCount - 1) * gutterX) + paddingW)) / barCount;
+    float barW = (1.0 - (paddingW + ((barCount - 1) * gutterW) + paddingW)) / barCount;
     float barHMax = 1.0 - (paddingH + paddingH);
 
     // Draw signal bar rectangles, then placeholder lines once strength reached
     for (uint8_t i = 0; i < barCount; i++) {
-        // Co-ords for this specific bar
+        // Coords for this specific bar
         float barH = barHMax * barHRel[i];
-        float barX = paddingW + (i * (gutterX + barW));
+        float barX = paddingW + (i * (gutterW + barW));
         float barY = paddingH + (barHMax - barH);
 
         // Rasterize to px coords at the last moment

src/graphics/niche/InkHUD/Applets/Bases/NodeList/NodeListApplet.h

@@ -23,13 +23,16 @@ Used by the "Recents" and "Heard" applets. Possibly more in future?
 
 #include "graphics/niche/InkHUD/Applet.h"
 
+#include "main.h"
+
 namespace NicheGraphics::InkHUD
 {
 
 class NodeListApplet : public Applet, public MeshModule
 {
   protected:
-    // Info used to draw one card to the node list
+    // Info needed to draw a node card to the list
+    // - generated each time we hear a node
     struct CardInfo {
         static constexpr uint8_t HOPS_UNKNOWN = -1;
         static constexpr uint32_t DISTANCE_UNKNOWN = -1;
@@ -37,31 +40,31 @@ class NodeListApplet : public Applet, public MeshModule
         NodeNum nodeNum = 0;
         SignalStrength signal = SignalStrength::SIGNAL_UNKNOWN;
         uint32_t distanceMeters = DISTANCE_UNKNOWN;
-        uint8_t hopsAway = HOPS_UNKNOWN; // Unknown
+        uint8_t hopsAway = HOPS_UNKNOWN;
     };
 
   public:
     NodeListApplet(const char *name);
+
     void onRender() override;
 
-    // MeshModule overrides
-    virtual bool wantPacket(const meshtastic_MeshPacket *p) override;
-    virtual ProcessMessage handleReceived(const meshtastic_MeshPacket &mp) override;
+    bool wantPacket(const meshtastic_MeshPacket *p) override;
+    ProcessMessage handleReceived(const meshtastic_MeshPacket &mp) override;
 
   protected:
-    virtual void handleParsed(CardInfo c) = 0; // Pass extracted info from a new packet to derived class, for sorting and storage
-    virtual std::string getHeaderText() = 0;   // Title for the applet's header. Todo: get this info another way?
+    virtual void handleParsed(CardInfo c) = 0; // Tell derived applet that we heard a node
+    virtual std::string getHeaderText() = 0;   // Ask derived class what the applet's title should be
 
-    uint8_t maxCards(); // Calculate the maximum number of cards an applet could ever display
+    uint8_t maxCards(); // Max number of cards which could ever fit on screen
 
-    std::deque<CardInfo> cards; // Derived applet places cards here, for this base applet to render
+    std::deque<CardInfo> cards; // Cards to be rendered. Derived applet fills this.
 
   private:
-    // UI element: a "mobile phone" style signal indicator
-    void drawSignalIndicator(int16_t x, int16_t y, uint16_t w, uint16_t h, SignalStrength signal);
+    void drawSignalIndicator(int16_t x, int16_t y, uint16_t w, uint16_t h,
+                             SignalStrength signal); // Draw a "mobile phone" style signal indicator
 
-    // Dimensions for drawing
-    // Used for render, and also for maxCards calc
+    // Card Dimensions
+    // - for rendering and for maxCards calc
     const uint8_t cardMarginH = fontSmall.lineHeight() / 2;                               // Gap between cards
     const uint16_t cardH = fontLarge.lineHeight() + fontSmall.lineHeight() + cardMarginH; // Height of card
 };

src/graphics/niche/InkHUD/Applets/Examples/NewMsgExample/NewMsgExampleApplet.cpp

@@ -36,8 +36,6 @@ ProcessMessage InkHUD::NewMsgExampleApplet::handleReceived(const meshtastic_Mesh
 // We should always be ready to draw
 void InkHUD::NewMsgExampleApplet::onRender()
 {
-    setFont(fontSmall);
-
     printAt(0, 0, "Example: NewMsg", LEFT, TOP); // Print top-left corner of text at (0,0)
 
     int16_t centerX = X(0.5); // Same as width() / 2

src/graphics/niche/InkHUD/Applets/Examples/NewMsgExample/NewMsgExampleApplet.h

@@ -53,7 +53,7 @@ class NewMsgExampleApplet : public Applet, public SinglePortModule
 
     // Store info from handleReceived
     bool haveMessage = false;
-    NodeNum fromWho;
+    NodeNum fromWho = 0;
 };
 
 } // namespace NicheGraphics::InkHUD

src/graphics/niche/InkHUD/Applets/System/BatteryIcon/BatteryIconApplet.cpp

@@ -4,10 +4,10 @@
 
 using namespace NicheGraphics;
 
-void InkHUD::BatteryIconApplet::onActivate()
+InkHUD::BatteryIconApplet::BatteryIconApplet()
 {
     // Show at boot, if user has previously enabled the feature
-    if (settings.optionalFeatures.batteryIcon)
+    if (settings->optionalFeatures.batteryIcon)
         bringToForeground();
 
     // Register to our have BatteryIconApplet::onPowerStatusUpdate method called when new power info is available
@@ -15,12 +15,6 @@ void InkHUD::BatteryIconApplet::onActivate()
     powerStatusObserver.observe(&powerStatus->onNewStatus);
 }
 
-void InkHUD::BatteryIconApplet::onDeactivate()
-{
-    // Stop having onPowerStatusUpdate called
-    powerStatusObserver.unobserve(&powerStatus->onNewStatus);
-}
-
 // We handle power status' even when the feature is disabled,
 // so that we have up to date data ready if the feature is enabled later.
 // Otherwise could be 30s before new status update, with weird battery value displayed
@@ -41,7 +35,7 @@ int InkHUD::BatteryIconApplet::onPowerStatusUpdate(const meshtastic::Status *sta
     // If rounded value has changed, trigger a display update
     // It's okay to requestUpdate before we store the new value, as the update won't run until next loop()
     // Don't trigger an update if the feature is disabled
-    if (this->socRounded != newSocRounded && settings.optionalFeatures.batteryIcon)
+    if (this->socRounded != newSocRounded && settings->optionalFeatures.batteryIcon)
         requestUpdate();
 
     // Store the new value

src/graphics/niche/InkHUD/Applets/System/BatteryIcon/BatteryIconApplet.h

@@ -11,24 +11,22 @@ It should be optional, enabled by the on-screen menu
 
 #include "configuration.h"
 
-#include "graphics/niche/InkHUD/Applet.h"
+#include "graphics/niche/InkHUD/SystemApplet.h"
 
 #include "PowerStatus.h"
 
 namespace NicheGraphics::InkHUD
 {
 
-class BatteryIconApplet : public Applet
+class BatteryIconApplet : public SystemApplet
 {
   public:
+    BatteryIconApplet();
+
     void onRender() override;
-
-    void onActivate() override;
-    void onDeactivate() override;
-
     int onPowerStatusUpdate(const meshtastic::Status *status); // Called when new info about battery is available
 
-  protected:
+  private:
     // Get informed when new information about the battery is available (via onPowerStatusUpdate method)
     CallbackObserver<BatteryIconApplet, const meshtastic::Status *> powerStatusObserver =
         CallbackObserver<BatteryIconApplet, const meshtastic::Status *>(this, &BatteryIconApplet::onPowerStatusUpdate);

src/graphics/niche/InkHUD/Applets/System/Logo/LogoApplet.cpp

@@ -2,15 +2,22 @@
 
 #include "./LogoApplet.h"
 
+#include "mesh/NodeDB.h"
+
 using namespace NicheGraphics;
 
 InkHUD::LogoApplet::LogoApplet() : concurrency::OSThread("LogoApplet")
 {
-    // Don't autostart the runOnce() timer
-    OSThread::disable();
+    OSThread::setIntervalFromNow(8 * 1000UL);
+    OSThread::enabled = true;
 
-    // Grab the WindowManager singleton, for convenience
-    windowManager = WindowManager::getInstance();
+    textLeft = "";
+    textRight = "";
+    textTitle = xstr(APP_VERSION_SHORT);
+    fontTitle = fontSmall;
+
+    bringToForeground();
+    // This is then drawn with a FULL refresh by Renderer::begin
 }
 
 void InkHUD::LogoApplet::onRender()
@@ -48,53 +55,24 @@ void InkHUD::LogoApplet::onRender()
 
 void InkHUD::LogoApplet::onForeground()
 {
-    // If another applet has locked the display, ask it to exit
-    Applet *other = windowManager->whoLocked();
-    if (other != nullptr)
-        other->sendToBackground();
-
-    windowManager->claimFullscreen(this); // Take ownership of fullscreen tile
-    windowManager->lock(this);            // Prevent other applets from requesting updates
+    SystemApplet::lockRendering = true;
+    SystemApplet::lockRequests = true;
+    SystemApplet::handleInput = true; // We don't actually use this input. Just blocking other applets from using it.
 }
 
 void InkHUD::LogoApplet::onBackground()
 {
-    OSThread::disable(); // Disable auto-dismiss timer, in case applet was dismissed early (sendToBackground from outside class)
-
-    windowManager->releaseFullscreen(); // Relinquish ownership of fullscreen tile
-    windowManager->unlock(this);        // Allow normal user applet update requests to resume
+    SystemApplet::lockRendering = false;
+    SystemApplet::lockRequests = false;
+    SystemApplet::handleInput = false;
 
     // Need to force an update, as a polite request wouldn't be honored, seeing how we are now in the background
     // Usually, onBackground is followed by another applet's onForeground (which requests update), but not in this case
-    windowManager->forceUpdate(EInk::UpdateTypes::FULL);
-}
-
-int32_t InkHUD::LogoApplet::runOnce()
-{
-    LOG_DEBUG("Sent to background by timer");
-    sendToBackground();
-    return OSThread::disable();
-}
-
-// Begin displaying the screen which is shown at startup
-// Suggest EInk::await after calling this method
-void InkHUD::LogoApplet::showBootScreen()
-{
-    OSThread::setIntervalFromNow(8 * 1000UL);
-    OSThread::enabled = true;
-
-    textLeft = "";
-    textRight = "";
-    textTitle = xstr(APP_VERSION_SHORT);
-    fontTitle = fontSmall;
-
-    bringToForeground();
-    requestUpdate(Drivers::EInk::UpdateTypes::FULL); // Already requested, just upgrading to FULL
+    inkhud->forceUpdate(EInk::UpdateTypes::FULL);
 }
 
 // Begin displaying the screen which is shown at shutdown
-// Needs EInk::await after calling this method, to ensure display updates before shutdown
-void InkHUD::LogoApplet::showShutdownScreen()
+void InkHUD::LogoApplet::onShutdown()
 {
     textLeft = "";
     textRight = "";
@@ -102,7 +80,13 @@ void InkHUD::LogoApplet::showShutdownScreen()
     fontTitle = fontLarge;
 
     bringToForeground();
-    requestUpdate(Drivers::EInk::UpdateTypes::FULL); // Already requested, just upgrading to FULL
+    // This is then drawn by InkHUD::Events::onShutdown, with a blocking FULL update
+}
+
+int32_t InkHUD::LogoApplet::runOnce()
+{
+    sendToBackground();
+    return OSThread::disable();
 }
 
 #endif

src/graphics/niche/InkHUD/Applets/System/Logo/LogoApplet.h

@@ -12,24 +12,19 @@
 #include "configuration.h"
 
 #include "concurrency/OSThread.h"
-#include "graphics/niche/InkHUD/Applet.h"
+#include "graphics/niche/InkHUD/SystemApplet.h"
 
 namespace NicheGraphics::InkHUD
 {
 
-class LogoApplet : public Applet, public concurrency::OSThread
+class LogoApplet : public SystemApplet, public concurrency::OSThread
 {
   public:
     LogoApplet();
     void onRender() override;
     void onForeground() override;
     void onBackground() override;
-
-    // Note: interacting directly with an applet like this is non-standard
-    // Only permitted because this is a "system applet", which has special behavior and interacts directly with WindowManager
-
-    void showBootScreen();
-    void showShutdownScreen();
+    void onShutdown() override;
 
   protected:
     int32_t runOnce() override;
@@ -38,8 +33,6 @@ class LogoApplet : public Applet, public concurrency::OSThread
     std::string textRight;
     std::string textTitle;
     AppletFont fontTitle;
-
-    WindowManager *windowManager = nullptr; // For convenience
 };
 
 } // namespace NicheGraphics::InkHUD

src/graphics/niche/InkHUD/Applets/System/Menu/MenuApplet.cpp

@@ -2,9 +2,11 @@
 
 #include "./MenuApplet.h"
 
-#include "PowerStatus.h"
 #include "RTC.h"
 
+#include "airtime.h"
+#include "power.h"
+
 using namespace NicheGraphics;
 
 static constexpr uint8_t MENU_TIMEOUT_SEC = 60; // How many seconds before menu auto-closes
@@ -17,23 +19,16 @@ InkHUD::MenuApplet::MenuApplet() : concurrency::OSThread("MenuApplet")
 {
     // No timer tasks at boot
     OSThread::disable();
-}
-
-void InkHUD::MenuApplet::onActivate()
-{
-    // Grab pointers to some singleton components which the menu interacts with
-    // We could do this every time we needed them, in place,
-    // but this just makes the code tidier
-
-    this->windowManager = WindowManager::getInstance();
 
     // Note: don't get instance if we're not actually using the backlight,
     // or else you will unintentionally instantiate it
-    if (settings.optionalMenuItems.backlight) {
+    if (settings->optionalMenuItems.backlight) {
         backlight = Drivers::LatchingBacklight::getInstance();
     }
 }
 
+void InkHUD::MenuApplet::onActivate() {}
+
 void InkHUD::MenuApplet::onForeground()
 {
     // We do need this before we render, but we can optimize by just calculating it once now
@@ -45,21 +40,23 @@ void InkHUD::MenuApplet::onForeground()
     // If device has a backlight which isn't controlled by aux button:
     // backlight on always when menu opens.
     // Courtesy to T-Echo users who removed the capacitive touch button
-    if (settings.optionalMenuItems.backlight) {
+    if (settings->optionalMenuItems.backlight) {
         assert(backlight);
         if (!backlight->isOn())
             backlight->peek();
     }
 
-    // Prevent user applets requested update while menu is open
-    windowManager->lock(this);
+    // Prevent user applets requesting update while menu is open
+    // Handle button input with this applet
+    SystemApplet::lockRequests = true;
+    SystemApplet::handleInput = true;
 
     // Begin the auto-close timeout
     OSThread::setIntervalFromNow(MENU_TIMEOUT_SEC * 1000UL);
     OSThread::enabled = true;
 
     // Upgrade the refresh to FAST, for guaranteed responsiveness
-    windowManager->forceUpdate(EInk::UpdateTypes::FAST);
+    inkhud->forceUpdate(EInk::UpdateTypes::FAST);
 }
 
 void InkHUD::MenuApplet::onBackground()
@@ -67,7 +64,7 @@ void InkHUD::MenuApplet::onBackground()
     // If device has a backlight which isn't controlled by aux button:
     // Item in options submenu allows keeping backlight on after menu is closed
     // If this item is deselected we will turn backlight off again, now that menu is closing
-    if (settings.optionalMenuItems.backlight) {
+    if (settings->optionalMenuItems.backlight) {
         assert(backlight);
         if (!backlight->isLatched())
             backlight->off();
@@ -77,7 +74,8 @@ void InkHUD::MenuApplet::onBackground()
     OSThread::disable();
 
     // Resume normal rendering and button behavior of user applets
-    windowManager->unlock(this);
+    SystemApplet::lockRequests = false;
+    SystemApplet::handleInput = false;
 
     // Restore the user applet whose tile we borrowed
     if (borrowedTileOwner)
@@ -87,8 +85,8 @@ void InkHUD::MenuApplet::onBackground()
     borrowedTileOwner = nullptr;
 
     // Need to force an update, as a polite request wouldn't be honored, seeing how we are now in the background
-    // We're only updating here to ugrade from UNSPECIFIED to FAST, to ensure responsiveness when exiting menu
-    windowManager->forceUpdate(EInk::UpdateTypes::FAST);
+    // We're only updating here to upgrade from UNSPECIFIED to FAST, to ensure responsiveness when exiting menu
+    inkhud->forceUpdate(EInk::UpdateTypes::FAST);
 }
 
 // Open the menu
@@ -140,43 +138,35 @@ void InkHUD::MenuApplet::execute(MenuItem item)
         break;
 
     case NEXT_TILE:
-        // Note performed manually;
-        // WindowManager::nextTile is raised by aux button press only, and will interact poorly with the menu
-        settings.userTiles.focused = (settings.userTiles.focused + 1) % settings.userTiles.count;
-        windowManager->changeLayout();
-        cursor = 0; // No menu item selected, for quick exit after tile swap
-        cursorShown = false;
+        inkhud->nextTile();
         break;
 
     case ROTATE:
-        settings.rotation = (settings.rotation + 1) % 4;
-        windowManager->changeLayout();
-        // requestUpdate(Drivers::EInk::UpdateTypes::FULL); // Would update regardless; just selecting FULL
+        inkhud->rotate();
         break;
 
     case LAYOUT:
         // Todo: smarter incrementing of tile count
-        settings.userTiles.count++;
+        settings->userTiles.count++;
 
-        if (settings.userTiles.count == 3) // Skip 3 tiles: not done yet
-            settings.userTiles.count++;
+        if (settings->userTiles.count == 3) // Skip 3 tiles: not done yet
+            settings->userTiles.count++;
 
-        if (settings.userTiles.count > settings.userTiles.maxCount) // Loop around if tile count now too high
-            settings.userTiles.count = 1;
+        if (settings->userTiles.count > settings->userTiles.maxCount) // Loop around if tile count now too high
+            settings->userTiles.count = 1;
 
-        windowManager->changeLayout();
-        // requestUpdate(Drivers::EInk::UpdateTypes::FULL); // Would update regardless; just selecting FULL
+        inkhud->updateLayout();
         break;
 
     case TOGGLE_APPLET:
-        settings.userApplets.active[cursor] = !settings.userApplets.active[cursor];
-        windowManager->changeActivatedApplets();
+        settings->userApplets.active[cursor] = !settings->userApplets.active[cursor];
+        inkhud->updateAppletSelection();
         // requestUpdate(Drivers::EInk::UpdateTypes::FULL); // Select FULL, seeing how this action doesn't auto exit
         break;
 
     case ACTIVATE_APPLETS:
         // Todo: remove this action? Already handled by TOGGLE_APPLET?
-        windowManager->changeActivatedApplets();
+        inkhud->updateAppletSelection();
         break;
 
     case TOGGLE_AUTOSHOW_APPLET:
@@ -185,14 +175,14 @@ void InkHUD::MenuApplet::execute(MenuItem item)
         break;
 
     case TOGGLE_NOTIFICATIONS:
-        settings.optionalFeatures.notifications = !settings.optionalFeatures.notifications;
+        settings->optionalFeatures.notifications = !settings->optionalFeatures.notifications;
         break;
 
     case SET_RECENTS:
         // Set value of settings.recentlyActiveSeconds
         // Uses menu cursor to read RECENTS_OPTIONS_MINUTES array (defined at top of this file)
         assert(cursor < sizeof(RECENTS_OPTIONS_MINUTES) / sizeof(RECENTS_OPTIONS_MINUTES[0]));
-        settings.recentlyActiveSeconds = RECENTS_OPTIONS_MINUTES[cursor] * 60; // Menu items are in minutes
+        settings->recentlyActiveSeconds = RECENTS_OPTIONS_MINUTES[cursor] * 60; // Menu items are in minutes
         break;
 
     case SHUTDOWN:
@@ -202,7 +192,7 @@ void InkHUD::MenuApplet::execute(MenuItem item)
         break;
 
     case TOGGLE_BATTERY_ICON:
-        windowManager->toggleBatteryIcon();
+        inkhud->toggleBatteryIcon();
         break;
 
     case TOGGLE_BACKLIGHT:
@@ -233,13 +223,13 @@ void InkHUD::MenuApplet::showPage(MenuPage page)
     switch (page) {
     case ROOT:
         // Optional: next applet
-        if (settings.optionalMenuItems.nextTile && settings.userTiles.count > 1)
+        if (settings->optionalMenuItems.nextTile && settings->userTiles.count > 1)
             items.push_back(MenuItem("Next Tile", MenuAction::NEXT_TILE, MenuPage::ROOT)); // Only if multiple applets shown
 
         // items.push_back(MenuItem("Send", MenuPage::SEND)); // TODO
         items.push_back(MenuItem("Options", MenuPage::OPTIONS));
         // items.push_back(MenuItem("Display Off", MenuPage::EXIT)); // TODO
-        items.push_back(MenuItem("Save & Shutdown", MenuAction::SHUTDOWN));
+        items.push_back(MenuItem("Save & Shut Down", MenuAction::SHUTDOWN));
         items.push_back(MenuItem("Exit", MenuPage::EXIT));
         break;
 
@@ -252,7 +242,7 @@ void InkHUD::MenuApplet::showPage(MenuPage page)
 
     case OPTIONS:
         // Optional: backlight
-        if (settings.optionalMenuItems.backlight) {
+        if (settings->optionalMenuItems.backlight) {
             assert(backlight);
             items.push_back(MenuItem(backlight->isLatched() ? "Backlight Off" : "Keep Backlight On", // Label
                                      MenuAction::TOGGLE_BACKLIGHT,                                   // Action
@@ -263,13 +253,13 @@ void InkHUD::MenuApplet::showPage(MenuPage page)
         items.push_back(MenuItem("Applets", MenuPage::APPLETS));
         items.push_back(MenuItem("Auto-show", MenuPage::AUTOSHOW));
         items.push_back(MenuItem("Recents Duration", MenuPage::RECENTS));
-        if (settings.userTiles.maxCount > 1)
+        if (settings->userTiles.maxCount > 1)
             items.push_back(MenuItem("Layout", MenuAction::LAYOUT, MenuPage::OPTIONS));
         items.push_back(MenuItem("Rotate", MenuAction::ROTATE, MenuPage::OPTIONS));
         items.push_back(MenuItem("Notifications", MenuAction::TOGGLE_NOTIFICATIONS, MenuPage::OPTIONS,
-                                 &settings.optionalFeatures.notifications));
-        items.push_back(
-            MenuItem("Battery Icon", MenuAction::TOGGLE_BATTERY_ICON, MenuPage::OPTIONS, &settings.optionalFeatures.batteryIcon));
+                                 &settings->optionalFeatures.notifications));
+        items.push_back(MenuItem("Battery Icon", MenuAction::TOGGLE_BATTERY_ICON, MenuPage::OPTIONS,
+                                 &settings->optionalFeatures.batteryIcon));
 
         // TODO - GPS and Wifi switches
         /*
@@ -329,9 +319,6 @@ void InkHUD::MenuApplet::onRender()
     if (items.size() == 0)
         LOG_ERROR("Empty Menu");
 
-    // Testing only
-    setFont(fontSmall);
-
     // Dimensions for the slots where we will draw menuItems
     const float padding = 0.05;
     const uint16_t itemH = fontSmall.lineHeight() * 2;
@@ -397,7 +384,7 @@ void InkHUD::MenuApplet::onRender()
 
         // Testing only: circle instead of check box
         if (item.checkState) {
-            const uint16_t cbWH = fontSmall.lineHeight();  // Checbox: width / height
+            const uint16_t cbWH = fontSmall.lineHeight();  // Checkbox: width / height
             const int16_t cbL = itemR - X(padding) - cbWH; // Checkbox: left
             const int16_t cbT = center - (cbWH / 2);       // Checkbox : top
             // Checkbox ticked
@@ -463,9 +450,9 @@ void InkHUD::MenuApplet::populateAppletPage()
 {
     assert(items.size() == 0);
 
-    for (uint8_t i = 0; i < windowManager->getAppletCount(); i++) {
-        const char *name = windowManager->getAppletName(i);
-        bool *isActive = &(settings.userApplets.active[i]);
+    for (uint8_t i = 0; i < inkhud->userApplets.size(); i++) {
+        const char *name = inkhud->userApplets.at(i)->name;
+        bool *isActive = &(settings->userApplets.active[i]);
         items.push_back(MenuItem(name, MenuAction::TOGGLE_APPLET, MenuPage::APPLETS, isActive));
     }
 }
@@ -477,11 +464,11 @@ void InkHUD::MenuApplet::populateAutoshowPage()
 {
     assert(items.size() == 0);
 
-    for (uint8_t i = 0; i < windowManager->getAppletCount(); i++) {
+    for (uint8_t i = 0; i < inkhud->userApplets.size(); i++) {
         // Only add a menu item if applet is active
-        if (settings.userApplets.active[i]) {
-            const char *name = windowManager->getAppletName(i);
-            bool *isActive = &(settings.userApplets.autoshow[i]);
+        if (settings->userApplets.active[i]) {
+            const char *name = inkhud->userApplets.at(i)->name;
+            bool *isActive = &(settings->userApplets.autoshow[i]);
             items.push_back(MenuItem(name, MenuAction::TOGGLE_AUTOSHOW_APPLET, MenuPage::AUTOSHOW, isActive));
         }
     }
@@ -599,10 +586,10 @@ void InkHUD::MenuApplet::drawSystemInfoPanel(int16_t left, int16_t top, uint16_t
 
 // Get the height of the the panel drawn at the top of the menu
 // This is inefficient, as we do actually have to render the panel to determine the height
-// It solves a catch-22 situtation, where slotCount needs to know panel height, and panel height needs to know slotCount
+// It solves a catch-22 situation, where slotCount needs to know panel height, and panel height needs to know slotCount
 uint16_t InkHUD::MenuApplet::getSystemInfoPanelHeight()
 {
-    // Render *waay* off screen
+    // Render *far* off screen
     uint16_t height = 0;
     drawSystemInfoPanel(INT16_MIN, INT16_MIN, 1, &height);
 

src/graphics/niche/InkHUD/Applets/System/Menu/MenuApplet.h

@@ -3,8 +3,9 @@
 #include "configuration.h"
 
 #include "graphics/niche/Drivers/Backlight/LatchingBacklight.h"
-#include "graphics/niche/InkHUD/Applet.h"
-#include "graphics/niche/InkHUD/WindowManager.h"
+#include "graphics/niche/InkHUD/InkHUD.h"
+#include "graphics/niche/InkHUD/Persistence.h"
+#include "graphics/niche/InkHUD/SystemApplet.h"
 
 #include "./MenuItem.h"
 #include "./MenuPage.h"
@@ -16,7 +17,7 @@ namespace NicheGraphics::InkHUD
 
 class Applet;
 
-class MenuApplet : public Applet, public concurrency::OSThread
+class MenuApplet : public SystemApplet, public concurrency::OSThread
 {
   public:
     MenuApplet();
@@ -30,6 +31,8 @@ class MenuApplet : public Applet, public concurrency::OSThread
     void show(Tile *t); // Open the menu, onto a user tile
 
   protected:
+    Drivers::LatchingBacklight *backlight = nullptr; // Convenient access to the backlight singleton
+
     int32_t runOnce() override;
 
     void execute(MenuItem item);  // Perform the MenuAction associated with a MenuItem, if any
@@ -41,7 +44,7 @@ class MenuApplet : public Applet, public concurrency::OSThread
     void drawSystemInfoPanel(int16_t left, int16_t top, uint16_t width,
                              uint16_t *height = nullptr); // Info panel at top of root menu
 
-    MenuPage currentPage;
+    MenuPage currentPage = MenuPage::ROOT;
     uint8_t cursor = 0;       // Which menu item is currently highlighted
     bool cursorShown = false; // Is *any* item highlighted? (Root menu: no initial selection)
 
@@ -50,9 +53,6 @@ class MenuApplet : public Applet, public concurrency::OSThread
     std::vector<MenuItem> items; // MenuItems for the current page. Filled by ShowPage
 
     Applet *borrowedTileOwner = nullptr; // Which applet we have temporarily replaced while displaying menu
-
-    WindowManager *windowManager = nullptr;          // Convenient access to the InkHUD::WindowManager singleton
-    Drivers::LatchingBacklight *backlight = nullptr; // Convenient access to the backlight singleton
 };
 
 } // namespace NicheGraphics::InkHUD

src/graphics/niche/InkHUD/Applets/System/Notification/NotificationApplet.cpp

@@ -3,22 +3,20 @@
 #include "./NotificationApplet.h"
 
 #include "./Notification.h"
+#include "graphics/niche/InkHUD/Persistence.h"
+
+#include "meshUtils.h"
+#include "modules/TextMessageModule.h"
 
 #include "RTC.h"
 
 using namespace NicheGraphics;
 
-void InkHUD::NotificationApplet::onActivate()
+InkHUD::NotificationApplet::NotificationApplet()
 {
     textMessageObserver.observe(textMessageModule);
 }
 
-// Note: This applet probably won't ever be deactivated
-void InkHUD::NotificationApplet::onDeactivate()
-{
-    textMessageObserver.unobserve(textMessageModule);
-}
-
 // Collect meta-info about the text message, and ask for approval for the notification
 // No need to save the message itself; we can use the cached InkHUD::latestMessage data during render()
 int InkHUD::NotificationApplet::onReceiveTextMessage(const meshtastic_MeshPacket *p)
@@ -28,7 +26,7 @@ int InkHUD::NotificationApplet::onReceiveTextMessage(const meshtastic_MeshPacket
 
     // Abort if feature disabled
     // This is a bit clumsy, but avoids complicated handling when the feature is enabled / disabled
-    if (!settings.optionalFeatures.notifications)
+    if (!settings->optionalFeatures.notifications)
         return 0;
 
     // Abort if this is an outgoing message
@@ -36,7 +34,7 @@ int InkHUD::NotificationApplet::onReceiveTextMessage(const meshtastic_MeshPacket
         return 0;
 
     // Abort if message was only an "emoji reaction"
-    // Possibly some implemetation of this in future?
+    // Possibly some implementation of this in future?
     if (p->decoded.emoji)
         return 0;
 
@@ -55,13 +53,16 @@ int InkHUD::NotificationApplet::onReceiveTextMessage(const meshtastic_MeshPacket
         n.sender = p->from;
     }
 
+    // Close an old notification, if shown
+    dismiss();
+
     // Check if we should display the notification
     // A foreground applet might already be displaying this info
     hasNotification = true;
     currentNotification = n;
     if (isApproved()) {
         bringToForeground();
-        WindowManager::getInstance()->forceUpdate();
+        inkhud->forceUpdate();
     } else
         hasNotification = false; // Clear the pending notification: it was rejected
 
@@ -76,8 +77,6 @@ void InkHUD::NotificationApplet::onRender()
     // We do need to do this with the battery though, as it is an "overlay"
     fillRect(0, 0, width(), height(), WHITE);
 
-    setFont(fontSmall);
-
     // Padding (horizontal)
     const uint16_t padW = 4;
 
@@ -137,6 +136,28 @@ void InkHUD::NotificationApplet::onRender()
     printThick(textM, height() / 2, text, 2, 1);
 }
 
+void InkHUD::NotificationApplet::onForeground()
+{
+    handleInput = true; // Intercept the button input for our applet, so we can dismiss the notification
+}
+
+void InkHUD::NotificationApplet::onBackground()
+{
+    handleInput = false;
+}
+
+void InkHUD::NotificationApplet::onButtonShortPress()
+{
+    dismiss();
+    inkhud->forceUpdate(EInk::UpdateTypes::FULL);
+}
+
+void InkHUD::NotificationApplet::onButtonLongPress()
+{
+    dismiss();
+    inkhud->forceUpdate(EInk::UpdateTypes::FULL);
+}
+
 // Ask the WindowManager to check whether any displayed applets are already displaying the info from this notification
 // Called internally when we first get a "notifiable event", and then again before render,
 // in case autoshow swapped which applet was displayed
@@ -148,7 +169,13 @@ bool InkHUD::NotificationApplet::isApproved()
         return false;
     }
 
-    return WindowManager::getInstance()->approveNotification(currentNotification);
+    // Ask all visible user applets for approval
+    for (Applet *ua : inkhud->userApplets) {
+        if (ua->isForeground() && !ua->approveNotification(currentNotification))
+            return false;
+    }
+
+    return true;
 }
 
 // Mark that the notification should no-longer be rendered
@@ -180,7 +207,8 @@ std::string InkHUD::NotificationApplet::getNotificationText(uint16_t widthAvaila
         bool isBroadcast = currentNotification.type == Notification::Type::NOTIFICATION_MESSAGE_BROADCAST;
 
         // Pick source of message
-        MessageStore::Message *message = isBroadcast ? &latestMessage.broadcast : &latestMessage.dm;
+        MessageStore::Message *message =
+            isBroadcast ? &inkhud->persistence->latestMessage.broadcast : &inkhud->persistence->latestMessage.dm;
 
         // Find info about the sender
         meshtastic_NodeInfoLite *node = nodeDB->getMeshNode(message->sender);

src/graphics/niche/InkHUD/Applets/System/Notification/NotificationApplet.h

@@ -3,7 +3,7 @@
 /*
 
 Pop-up notification bar, on screen top edge
-Displays information we feel is important, but which is not shown on currently focussed applet(s)
+Displays information we feel is important, but which is not shown on currently focused applet(s)
 E.g.: messages, while viewing map, etc
 
 Feature should be optional; enable disable via on-screen menu
@@ -16,17 +16,21 @@ Feature should be optional; enable disable via on-screen menu
 
 #include "concurrency/OSThread.h"
 
-#include "graphics/niche/InkHUD/Applet.h"
+#include "graphics/niche/InkHUD/SystemApplet.h"
 
 namespace NicheGraphics::InkHUD
 {
 
-class NotificationApplet : public Applet
+class NotificationApplet : public SystemApplet
 {
   public:
+    NotificationApplet();
+
     void onRender() override;
-    void onActivate() override;
-    void onDeactivate() override;
+    void onForeground() override;
+    void onBackground() override;
+    void onButtonShortPress() override;
+    void onButtonLongPress() override;
 
     int onReceiveTextMessage(const meshtastic_MeshPacket *p);
 
@@ -40,8 +44,8 @@ class NotificationApplet : public Applet
 
     std::string getNotificationText(uint16_t widthAvailable); // Get text for notification, to suit screen width
 
-    bool hasNotification = false;     // Only used for assert. Todo: remove?
-    Notification currentNotification; // Set when something notification-worthy happens. Used by render()
+    bool hasNotification = false;                      // Only used for assert. Todo: remove?
+    Notification currentNotification = Notification(); // Set when something notification-worthy happens. Used by render()
 };
 
 } // namespace NicheGraphics::InkHUD

src/graphics/niche/InkHUD/Applets/System/Pairing/PairingApplet.cpp

@@ -6,8 +6,7 @@ using namespace NicheGraphics;
 
 InkHUD::PairingApplet::PairingApplet()
 {
-    // Grab the window manager singleton, for convenience
-    windowManager = WindowManager::getInstance();
+    bluetoothStatusObserver.observe(&bluetoothStatus->onNewStatus);
 }
 
 void InkHUD::PairingApplet::onRender()
@@ -31,34 +30,22 @@ void InkHUD::PairingApplet::onRender()
         printAt(X(0.5), Y(0.75), name, CENTER, MIDDLE);
 }
 
-void InkHUD::PairingApplet::onActivate()
-{
-    bluetoothStatusObserver.observe(&bluetoothStatus->onNewStatus);
-}
-
-void InkHUD::PairingApplet::onDeactivate()
-{
-    bluetoothStatusObserver.unobserve(&bluetoothStatus->onNewStatus);
-}
-
 void InkHUD::PairingApplet::onForeground()
 {
-    // If another applet has locked the display, ask it to exit
-    Applet *other = windowManager->whoLocked();
-    if (other != nullptr)
-        other->sendToBackground();
-
-    windowManager->claimFullscreen(this); // Take ownership of the fullscreen tile
-    windowManager->lock(this);            // Prevent user applets from requesting update
+    // Prevent most other applets from requesting update, and skip their rendering entirely
+    // Another system applet with a higher precedence can potentially ignore this
+    SystemApplet::lockRendering = true;
+    SystemApplet::lockRequests = true;
 }
 void InkHUD::PairingApplet::onBackground()
 {
-    windowManager->releaseFullscreen(); // Relinquish ownership of the fullscreen tile
-    windowManager->unlock(this);        // Allow normal user applet update requests to resume
+    // Allow normal update behavior to resume
+    SystemApplet::lockRendering = false;
+    SystemApplet::lockRequests = false;
 
     // Need to force an update, as a polite request wouldn't be honored, seeing how we are now in the background
     // Usually, onBackground is followed by another applet's onForeground (which requests update), but not in this case
-    windowManager->forceUpdate(EInk::UpdateTypes::FULL);
+    inkhud->forceUpdate(EInk::UpdateTypes::FULL);
 }
 
 int InkHUD::PairingApplet::onBluetoothStatusUpdate(const meshtastic::Status *status)
@@ -75,12 +62,6 @@ int InkHUD::PairingApplet::onBluetoothStatusUpdate(const meshtastic::Status *sta
         // Store the passkey for rendering
         passkey = bluetoothStatus->getPasskey();
 
-        // Make sure no other system applets have a lock on the display
-        // Boot screen, menu, etc
-        Applet *lockOwner = windowManager->whoLocked();
-        if (lockOwner)
-            lockOwner->sendToBackground();
-
         // Show pairing screen
         bringToForeground();
     }

src/graphics/niche/InkHUD/Applets/System/Pairing/PairingApplet.h

@@ -10,19 +10,19 @@
 
 #include "configuration.h"
 
-#include "graphics/niche/InkHUD/Applet.h"
+#include "graphics/niche/InkHUD/SystemApplet.h"
+
+#include "main.h"
 
 namespace NicheGraphics::InkHUD
 {
 
-class PairingApplet : public Applet
+class PairingApplet : public SystemApplet
 {
   public:
     PairingApplet();
 
     void onRender() override;
-    void onActivate() override;
-    void onDeactivate() override;
     void onForeground() override;
     void onBackground() override;
 
@@ -34,8 +34,6 @@ class PairingApplet : public Applet
         CallbackObserver<PairingApplet, const meshtastic::Status *>(this, &PairingApplet::onBluetoothStatusUpdate);
 
     std::string passkey = ""; // Passkey. Six digits, possibly with leading zeros
-
-    WindowManager *windowManager = nullptr; // For convenience. Set in constructor.
 };
 
 } // namespace NicheGraphics::InkHUD

src/graphics/niche/InkHUD/Applets/System/Placeholder/PlaceholderApplet.cpp

@@ -4,14 +4,6 @@
 
 using namespace NicheGraphics;
 
-InkHUD::PlaceholderApplet::PlaceholderApplet()
-{
-    // Because this applet sometimes gets processed as if it were a bonafide user applet,
-    // it's probably better that we do give it a human readable name, just in case it comes up later.
-    // For genuine user applets, this is set by WindowManager::addApplet
-    Applet::name = "Placeholder";
-}
-
 void InkHUD::PlaceholderApplet::onRender()
 {
     // This placeholder applet fills its area with sparse diagonal lines

src/graphics/niche/InkHUD/Applets/System/Placeholder/PlaceholderApplet.h

@@ -9,20 +9,19 @@ Fills the area with diagonal lines
 
 #include "configuration.h"
 
-#include "graphics/niche/InkHUD/Applet.h"
+#include "graphics/niche/InkHUD/SystemApplet.h"
 
 namespace NicheGraphics::InkHUD
 {
 
-class PlaceholderApplet : public Applet
+class PlaceholderApplet : public SystemApplet
 {
   public:
-    PlaceholderApplet();
     void onRender() override;
 
     // Note: onForeground, onBackground, and wantsToRender are not meaningful for this applet.
     // The window manager decides when and where it should be rendered
-    // It may be drawn to several different tiles during on WindowManager::render call
+    // It may be drawn to several different tiles during an Renderer::render call
 };
 
 } // namespace NicheGraphics::InkHUD

src/graphics/niche/InkHUD/Applets/System/Tips/TipsApplet.cpp

@@ -2,12 +2,44 @@
 
 #include "./TipsApplet.h"
 
+#include "graphics/niche/InkHUD/Persistence.h"
+
+#include "main.h"
+
 using namespace NicheGraphics;
 
 InkHUD::TipsApplet::TipsApplet()
 {
-    // Grab the window manager singleton, for convenience
-    windowManager = WindowManager::getInstance();
+    // Decide which tips (if any) should be shown to user after the boot screen
+
+    // Welcome screen
+    if (settings->tips.firstBoot)
+        tipQueue.push_back(Tip::WELCOME);
+
+    // Antenna, region, timezone
+    // Shown at boot if region not yet set
+    if (config.lora.region == meshtastic_Config_LoRaConfig_RegionCode_UNSET)
+        tipQueue.push_back(Tip::FINISH_SETUP);
+
+    // Shutdown info
+    // Shown until user performs one valid shutdown
+    if (!settings->tips.safeShutdownSeen)
+        tipQueue.push_back(Tip::SAFE_SHUTDOWN);
+
+    // Using the UI
+    if (settings->tips.firstBoot) {
+        tipQueue.push_back(Tip::CUSTOMIZATION);
+        tipQueue.push_back(Tip::BUTTONS);
+    }
+
+    // Catch an incorrect attempt at rotating display
+    if (config.display.flip_screen)
+        tipQueue.push_back(Tip::ROTATION);
+
+    // Applet is foreground immediately at boot, but is obscured by LogoApplet, which is also foreground
+    // LogoApplet can be considered to have a higher Z-index, because it is placed before TipsApplet in the systemApplets vector
+    if (!tipQueue.empty())
+        bringToForeground();
 }
 
 void InkHUD::TipsApplet::onRender()
@@ -53,7 +85,7 @@ void InkHUD::TipsApplet::onRender()
 
         setFont(fontSmall);
         std::string shutdown;
-        shutdown += "Before removing power, please shutdown from InkHUD menu, or a client app. \n";
+        shutdown += "Before removing power, please shut down from InkHUD menu, or a client app. \n";
         shutdown += "\n";
         shutdown += "This ensures data is saved.";
         printWrapped(0, fontLarge.lineHeight() * 1.5, width(), shutdown);
@@ -153,51 +185,31 @@ void InkHUD::TipsApplet::renderWelcome()
     printAt(X(0.5), Y(1), "Press button to continue", CENTER, BOTTOM);
 }
 
-// Grab fullscreen tile, and lock the window manager, when applet is shown
 void InkHUD::TipsApplet::onForeground()
 {
-    windowManager->lock(this);
-    windowManager->claimFullscreen(this);
+    // Prevent most other applets from requesting update, and skip their rendering entirely
+    // Another system applet with a higher precedence can potentially ignore this
+    SystemApplet::lockRendering = true;
+    SystemApplet::lockRequests = true;
+
+    SystemApplet::handleInput = true; // Our applet should handle button input (unless another system applet grabs it first)
 }
 
 void InkHUD::TipsApplet::onBackground()
 {
-    windowManager->releaseFullscreen();
-    windowManager->unlock(this);
+    // Allow normal update behavior to resume
+    SystemApplet::lockRendering = false;
+    SystemApplet::lockRequests = false;
+    SystemApplet::handleInput = false;
+
+    // Need to force an update, as a polite request wouldn't be honored, seeing how we are now in the background
+    // Usually, onBackground is followed by another applet's onForeground (which requests update), but not in this case
+    inkhud->forceUpdate(EInk::UpdateTypes::FULL);
 }
 
-void InkHUD::TipsApplet::onActivate()
-{
-    // Decide which tips (if any) should be shown to user after the boot screen
+void InkHUD::TipsApplet::onActivate() {}
 
-    // Welcome screen
-    if (settings.tips.firstBoot)
-        tipQueue.push_back(Tip::WELCOME);
-
-    // Antenna, region, timezone
-    // Shown at boot if region not yet set
-    if (config.lora.region == meshtastic_Config_LoRaConfig_RegionCode_UNSET)
-        tipQueue.push_back(Tip::FINISH_SETUP);
-
-    // Shutdown info
-    // Shown until user performs one valid shutdown
-    if (!settings.tips.safeShutdownSeen)
-        tipQueue.push_back(Tip::SAFE_SHUTDOWN);
-
-    // Using the UI
-    if (settings.tips.firstBoot) {
-        tipQueue.push_back(Tip::CUSTOMIZATION);
-        tipQueue.push_back(Tip::BUTTONS);
-    }
-
-    // Catch an incorrect attempt at rotating display
-    if (config.display.flip_screen)
-        tipQueue.push_back(Tip::ROTATION);
-
-    // Applet will be brought to foreground when boot screen closes, via TipsApplet::onLockAvailable
-}
-
-// While our applet has the window manager locked, we will receive the button input
+// While our SystemApplet::handleInput flag is true
 void InkHUD::TipsApplet::onButtonShortPress()
 {
     tipQueue.pop_front();
@@ -206,15 +218,15 @@ void InkHUD::TipsApplet::onButtonShortPress()
     if (tipQueue.empty()) {
         // Record that user has now seen the "tutorial" set of tips
         // Don't show them on subsequent boots
-        if (settings.tips.firstBoot) {
-            settings.tips.firstBoot = false;
-            saveDataToFlash();
+        if (settings->tips.firstBoot) {
+            settings->tips.firstBoot = false;
+            inkhud->persistence->saveSettings();
         }
 
         // Close applet, and full refresh to clean the screen
         // Need to force update, because our request would be ignored otherwise, as we are now background
         sendToBackground();
-        windowManager->forceUpdate(EInk::UpdateTypes::FULL);
+        inkhud->forceUpdate(EInk::UpdateTypes::FULL);
     }
 
     // More tips left
@@ -222,13 +234,4 @@ void InkHUD::TipsApplet::onButtonShortPress()
         requestUpdate();
 }
 
-// If the wm lock has just become availale (rendering, input), and we've still got tips, grab it!
-// This situation would arise if bluetooth pairing occurs while TipsApplet was already shown (after pairing)
-// Note: this event is only raised when *other* applets unlock the window manager
-void InkHUD::TipsApplet::onLockAvailable()
-{
-    if (!tipQueue.empty())
-        bringToForeground();
-}
-
 #endif

src/graphics/niche/InkHUD/Applets/System/Tips/TipsApplet.h

@@ -12,12 +12,12 @@
 
 #include "configuration.h"
 
-#include "graphics/niche/InkHUD/Applet.h"
+#include "graphics/niche/InkHUD/SystemApplet.h"
 
 namespace NicheGraphics::InkHUD
 {
 
-class TipsApplet : public Applet
+class TipsApplet : public SystemApplet
 {
   protected:
     enum class Tip {
@@ -37,7 +37,6 @@ class TipsApplet : public Applet
     void onForeground() override;
     void onBackground() override;
     void onButtonShortPress() override;
-    void onLockAvailable() override; // Reopen if interrupted by bluetooth pairing
 
   protected:
     void renderWelcome(); // Very first screen of tutorial

src/graphics/niche/InkHUD/Applets/User/AllMessage/AllMessageApplet.cpp

@@ -41,14 +41,12 @@ int InkHUD::AllMessageApplet::onReceiveTextMessage(const meshtastic_MeshPacket *
 
 void InkHUD::AllMessageApplet::onRender()
 {
-    setFont(fontSmall);
-
     // Find newest message, regardless of whether DM or broadcast
     MessageStore::Message *message;
-    if (latestMessage.wasBroadcast)
-        message = &latestMessage.broadcast;
+    if (latestMessage->wasBroadcast)
+        message = &latestMessage->broadcast;
     else
-        message = &latestMessage.dm;
+        message = &latestMessage->dm;
 
     // Short circuit: no text message
     if (!message->sender) {

src/graphics/niche/InkHUD/Applets/User/DM/DMApplet.cpp

@@ -44,10 +44,8 @@ int InkHUD::DMApplet::onReceiveTextMessage(const meshtastic_MeshPacket *p)
 
 void InkHUD::DMApplet::onRender()
 {
-    setFont(fontSmall);
-
     // Abort if no text message
-    if (!latestMessage.dm.sender) {
+    if (!latestMessage->dm.sender) {
         printAt(X(0.5), Y(0.5), "No DMs", CENTER, MIDDLE);
         return;
     }
@@ -63,7 +61,7 @@ void InkHUD::DMApplet::onRender()
 
     // RX Time
     // - if valid
-    std::string timeString = getTimeString(latestMessage.dm.timestamp);
+    std::string timeString = getTimeString(latestMessage->dm.timestamp);
     if (timeString.length() > 0) {
         header += timeString;
         header += ": ";
@@ -72,14 +70,14 @@ void InkHUD::DMApplet::onRender()
     // Sender's id
     // - shortname, if available, or
     // - node id
-    meshtastic_NodeInfoLite *sender = nodeDB->getMeshNode(latestMessage.dm.sender);
+    meshtastic_NodeInfoLite *sender = nodeDB->getMeshNode(latestMessage->dm.sender);
     if (sender && sender->has_user) {
         header += sender->user.short_name;
         header += " (";
         header += sender->user.long_name;
         header += ")";
     } else
-        header += hexifyNodeNum(latestMessage.dm.sender);
+        header += hexifyNodeNum(latestMessage->dm.sender);
 
     // Draw a "standard" applet header
     drawHeader(header);
@@ -103,14 +101,14 @@ void InkHUD::DMApplet::onRender()
 
     // Determine size if printed large
     setFont(fontLarge);
-    uint32_t textHeight = getWrappedTextHeight(0, width(), latestMessage.dm.text);
+    uint32_t textHeight = getWrappedTextHeight(0, width(), latestMessage->dm.text);
 
     // If too large, swap to small font
     if (textHeight + textTop > (uint32_t)height()) // (compare signed and unsigned)
         setFont(fontSmall);
 
     // Print text
-    printWrapped(0, textTop, width(), latestMessage.dm.text);
+    printWrapped(0, textTop, width(), latestMessage->dm.text);
 }
 
 // Don't show notifications for direct messages when our applet is displayed

src/graphics/niche/InkHUD/Applets/User/Positions/PositionsApplet.h

@@ -29,13 +29,13 @@ class PositionsApplet : public MapApplet, public SinglePortModule
   protected:
     ProcessMessage handleReceived(const meshtastic_MeshPacket &mp) override;
 
-    NodeNum lastFrom; // Sender of most recent (non-local) position packet
-    float lastLat;
-    float lastLng;
-    float lastHopsAway;
+    NodeNum lastFrom = 0; // Sender of most recent (non-local) position packet
+    float lastLat = 0.0;
+    float lastLng = 0.0;
+    float lastHopsAway = 0;
 
-    float ourLastLat; // Info about the most recent (non-local) position packet
-    float ourLastLng; // Info about most recent *local* position
+    float ourLastLat = 0.0; // Info about the most recent (non-local) position packet
+    float ourLastLng = 0.0; // Info about most recent *local* position
 };
 
 } // namespace NicheGraphics::InkHUD

src/graphics/niche/InkHUD/Applets/User/RecentsList/RecentsListApplet.cpp

@@ -122,7 +122,7 @@ bool InkHUD::RecentsListApplet::isActive(uint32_t seenAtMs)
     uint32_t now = millis();
     uint32_t secsAgo = (now - seenAtMs) / 1000UL; // millis() overflow safe
 
-    return (secsAgo < settings.recentlyActiveSeconds);
+    return (secsAgo < settings->recentlyActiveSeconds);
 }
 
 // Text to be shown at top of applet
@@ -134,7 +134,7 @@ std::string InkHUD::RecentsListApplet::getHeaderText()
 
     // Print the length of our "Recents" time-window
     text += "Last ";
-    text += to_string(settings.recentlyActiveSeconds / 60);
+    text += to_string(settings->recentlyActiveSeconds / 60);
     text += " mins";
 
     // Print the node count

src/graphics/niche/InkHUD/Applets/User/ThreadedMessage/ThreadedMessageApplet.cpp

@@ -23,8 +23,6 @@ InkHUD::ThreadedMessageApplet::ThreadedMessageApplet(uint8_t channelIndex) : cha
 
 void InkHUD::ThreadedMessageApplet::onRender()
 {
-    setFont(fontSmall);
-
     // =============
     // Draw a header
     // =============

src/graphics/niche/InkHUD/Applets/User/ThreadedMessage/ThreadedMessageApplet.h

@@ -33,7 +33,7 @@ class Applet;
 class ThreadedMessageApplet : public Applet
 {
   public:
-    ThreadedMessageApplet(uint8_t channelIndex);
+    explicit ThreadedMessageApplet(uint8_t channelIndex);
     ThreadedMessageApplet() = delete;
 
     void onRender() override;