Additional fixes - will be squashed

Add a truncated display of debug information in a system with no trade
Add NILing of Core.params if the calculation of the system parameters failed
Add NoBackground flag for fullscreen UI window options
Add a Log::Verbose when the body changes frame
Add const to GetRotFrame() function

data/modules/TradeShips/Debug.lua

@@ -54,7 +54,7 @@ local statuses = {
 }
 
 debugView.registerTab('debug-trade-ships', function()
-	if not Core.ships or not Core.params then return end
+	if not Core.ships and not Core.params then return end
 	if not ui.beginTabItem("Tradeships") then return end
 
 	local function property(key, value)
@@ -66,6 +66,7 @@ debugView.registerTab('debug-trade-ships', function()
 	end
 
 	ui.child("tradeships_as_child", Vector2(-1, -infosize), {"NoSavedSettings", "HorizontalScrollbar"}, function()
+		if Core.params then
 		if ui.collapsingHeader("System summary", {"DefaultOpen"}) then
 			local precalculated = {}
 			if Core.params.spawn_in then
@@ -200,6 +201,7 @@ debugView.registerTab('debug-trade-ships', function()
 				end
 			end
 		end
+		end
 
 		if ui.collapsingHeader("All ships") then
 			local ships = {}

data/modules/TradeShips/Flow.lua

@@ -84,6 +84,13 @@ local function getImportsExports(system)
 	return imports, exports
 end
 
+-- we do this if the calculation of the system parameters failed, and we need
+-- to return nil, and also execute some code
+local function noSystemParams()
+	Core.params = nil
+	return nil
+end
+
 -- we collect all the information necessary for the module to work in this system:
 -- valid ship models
 -- import / export goods
@@ -95,12 +102,12 @@ Flow.calculateSystemParams = function()
 	local system = Game.system
 
 	-- dont spawn tradeships in unpopulated systems
-	if system.population == 0 then return nil end
+	if system.population == 0 then return noSystemParams() end
 
 	-- all ports in the system
 	local ports = Space.GetBodies(function (body) return body.superType == 'STARPORT' end)
 	-- check if the current system can be traded in
-	if #ports == 0 then return nil end
+	if #ports == 0 then return noSystemParams() end
 
 	-- all routes in the system
 	-- routes are laid from the nearest star
@@ -118,12 +125,12 @@ Flow.calculateSystemParams = function()
 
 	-- get ships listed as tradeships, if none - give up
 	local ship_names = getAcceptableShips()
-	if #ship_names == 0 then return nil end
+	if #ship_names == 0 then return noSystemParams() end
 
 	local imports, exports = getImportsExports(system)
 
 	-- if there is no market then there is no trade
-	if #imports == 0 or #exports == 0 then return nil end
+	if #imports == 0 or #exports == 0 then return noSystemParams() end
 
 	-- all tradeship models array
 	-- these are real ship objects, they are needed for calculations
@@ -193,7 +200,7 @@ Flow.calculateSystemParams = function()
 	end
 
 	-- as a result, not a single ship might remain
-	if #ship_names == 0 then return nil end
+	if #ship_names == 0 then return noSystemParams() end
 
 	-- now we have only those ships that can jump from somewhere and land somewhere
 	-- now set the flow on the most popular route to MAX_ROUTE_FLOW

data/pigui/baseui.lua

@@ -25,19 +25,17 @@ ui.pi_4 = pi_4
 ui.pi = pi
 
 ui.anchor = { left = 1, right = 2, center = 3, top = 4, bottom = 5, baseline = 6 }
-ui.fullScreenWindowFlags = ui.WindowFlags {"NoTitleBar", "NoResize", "NoMove", "NoInputs", "NoSavedSettings", "NoFocusOnAppearing", "NoBringToFrontOnFocus"}
+ui.fullScreenWindowFlags = ui.WindowFlags { "NoTitleBar", "NoResize", "NoMove", "NoInputs", "NoSavedSettings", "NoFocusOnAppearing", "NoBringToFrontOnFocus", "NoBackground" }
 
 -- make all the necessary preparations for displaying the full-screen UI, launch the drawing function
 function ui.makeFullScreenHandler(window_name, window_fnc)
 	return function()
 		ui.setNextWindowPos(Vector2(0, 0), "Always")
 		ui.setNextWindowSize(Vector2(ui.screenWidth, ui.screenHeight), "Always")
-		ui.withStyleColors({ ["WindowBg"] = ui.theme.colors.transparent }, function()
-			ui.window(window_name, ui.fullScreenWindowFlags, function()
-				if ui.shouldDrawUI() then
-					window_fnc()
-				end
-			end)
+		ui.window(window_name, ui.fullScreenWindowFlags, function()
+			if ui.shouldDrawUI() then
+				window_fnc()
+			end
 		end)
 	end
 end

src/Body.cpp

@@ -234,7 +234,7 @@ void Body::UpdateFrame()
 		FrameId parent = frame->GetParent();
 		Frame *newFrame = Frame::GetFrame(parent);
 		if (newFrame) { // don't fall out of root frame
-			// Output("%s leaves frame %s\n", GetLabel().c_str(), frame->GetLabel().c_str());
+			Log::Verbose("{} leaves frame{}\n", GetLabel(), frame->GetLabel());
 			SwitchToFrame(parent);
 			return;
 		}
@@ -246,7 +246,7 @@ void Body::UpdateFrame()
 		const vector3d pos = GetPositionRelTo(kid);
 		if (pos.Length() >= kid_frame->GetRadius()) continue;
 		SwitchToFrame(kid);
-		// Output("%s enters frame %s\n", GetLabel().c_str(), kid_frame->GetLabel().c_str());
+		Log::Verbose("{} enters frame{}\n", GetLabel(), frame->GetLabel());
 		break;
 	}
 }

src/Frame.h

@@ -83,7 +83,7 @@ class Frame {
 
 	FrameId GetParent() const { return m_parent; }
 	FrameId GetNonRotFrame() const { return IsRotFrame() ? m_parent : m_thisId; }
-	FrameId GetRotFrame() { return HasRotFrame() ? m_children.front() : m_thisId; }
+	FrameId GetRotFrame() const { return HasRotFrame() ? m_children.front() : m_thisId; }
 
 	void SetBodies(SystemBody *s, Body *b)
 	{

src/lua/LuaPiGui.cpp

@@ -317,6 +317,7 @@ static LuaFlags<ImGuiWindowFlags_> imguiWindowFlagsTable = {
 	{ "NoScrollWithMouse", ImGuiWindowFlags_NoScrollWithMouse },
 	{ "NoCollapse", ImGuiWindowFlags_NoCollapse },
 	{ "AlwaysAutoResize", ImGuiWindowFlags_AlwaysAutoResize },
+	{ "NoBackground", ImGuiWindowFlags_NoBackground },
 	{ "NoSavedSettings", ImGuiWindowFlags_NoSavedSettings },
 	{ "NoInputs", ImGuiWindowFlags_NoInputs },
 	{ "MenuBar", ImGuiWindowFlags_MenuBar },

src/lua/LuaShip.cpp

@@ -668,7 +668,7 @@ static int l_ship_is_ecm_ready(lua_State *l)
  *   Calculating the duration of the flight of a given ship at a specified distance.
  *   Assumed that at the beginning and at the end of the travel the speed is 0.
  *
- * > duration = ship:GetDurationForDistancel(distance)
+ * > duration = ship:GetDurationForDistance(distance)
  *
  * Parameters:
  *