fix(lua): Store and update the 'zone' rectangle for Lua widgets. (#3060)

* Store 'zone' rectangle dat in Lua registry and update it when the screen layout changes or full screen mode changes. Allows Lua widgets to adjust to layout changes.

* Call widget 'update' function is layout has changed.

radio/src/lua/lua_widget.cpp

@@ -196,9 +196,10 @@ void LuaEventHandler::removeHandler(Window* w)
 
 LuaWidget::LuaWidget(const WidgetFactory* factory, Window* parent,
                      const rect_t& rect, WidgetPersistentData* persistentData,
-                     int luaWidgetDataRef) :
+                     int luaWidgetDataRef,int zoneRectDataRef) :
     Widget(factory, parent, rect, persistentData),
     luaWidgetDataRef(luaWidgetDataRef),
+    zoneRectDataRef(zoneRectDataRef),
     errorMessage(nullptr)
 {
 }
@@ -206,6 +207,7 @@ LuaWidget::LuaWidget(const WidgetFactory* factory, Window* parent,
 LuaWidget::~LuaWidget()
 {
   luaL_unref(lsWidgets, LUA_REGISTRYINDEX, luaWidgetDataRef);
+  luaL_unref(lsWidgets, LUA_REGISTRYINDEX, zoneRectDataRef);
   free(errorMessage);
 }
 
@@ -288,6 +290,53 @@ void LuaWidget::update()
   }
 }
 
+// Update table on top of Lua stack - set entry with name 'idx' to value 'val'
+// Return true if value has changed
+bool LuaWidget::updateTable(const char* idx, int val)
+{
+  bool update = false;
+
+  // Check existing value (or invalid value)
+  lua_getfield(lsWidgets, -1, idx);
+  if (lua_isnumber(lsWidgets, -1)) {
+    int v = lua_tointeger(lsWidgets, -1);
+    update = (v != val);
+  } else {
+    // Force table update
+    update = true;
+  }
+  lua_pop(lsWidgets, 1);
+
+  if (update) {
+    lua_pushinteger(lsWidgets, val);
+    lua_setfield(lsWidgets, -2, idx);
+  }
+
+  return update;
+}
+
+void LuaWidget::updateZoneRect(rect_t rect)
+{
+  if (lsWidgets)
+  {
+    // Update widget zone with current size and position
+
+    lua_rawgeti(lsWidgets, LUA_REGISTRYINDEX, zoneRectDataRef);
+
+    bool changed = false;
+
+    if (updateTable("w", rect.w)) changed = true;
+    if (updateTable("h", rect.h)) changed = true;
+    if (updateTable("xabs", rect.x)) changed = true;
+    if (updateTable("yabs", rect.y)) changed = true;
+
+    lua_pop(lsWidgets, 1);
+
+    if (changed)
+      update();
+  }
+}
+
 void LuaWidget::onFullscreen(bool enable)
 {
   if (enable) {