AI: Add in-game galaxy map as MapEditor canvas background

ZeroSpace/ZeroSpace.MapEditor/Views/MapDrawable.cs

@@ -1,5 +1,6 @@
 using Microsoft.Maui.Graphics;
 using ZeroSpace.MapEditor.Models;
+using ZeroSpace.MapEditor.Services;
 
 namespace ZeroSpace.MapEditor.Views;
 
@@ -25,11 +26,19 @@ public sealed class MapDrawable : IDrawable
 
     public RectF? SelectionBox { get; set; }
 
+    /// <summary>In-game galaxy map screenshot, drawn under the nodes.</summary>
+    public IImage? BackgroundImage { get; set; }
+
+    /// <summary>Whether the galaxy map background is shown.</summary>
+    public bool ShowBackground { get; set; } = true;
+
     public void Draw(ICanvas canvas, RectF dirtyRect)
     {
         canvas.FillColor = Color.FromArgb("#1e2430");
         canvas.FillRectangle(dirtyRect);
 
+        DrawBackground(canvas);
+
         PointF ToScreen(double worldX, double worldY) =>
             new((float)(worldX * Scale + OffsetX), (float)(worldY * Scale + OffsetY));
 
@@ -85,6 +94,39 @@ public sealed class MapDrawable : IDrawable
         }
     }
 
+    /// <summary>
+    /// Draws the galaxy map screenshot fitted inside the world square,
+    /// preserving aspect ratio so node world coordinates line up exactly
+    /// with the map underneath.
+    /// </summary>
+    private void DrawBackground(ICanvas canvas)
+    {
+        if (!ShowBackground || BackgroundImage is null)
+        {
+            return;
+        }
+
+        var imageWidth = BackgroundImage.Width;
+        var imageHeight = BackgroundImage.Height;
+        if (imageWidth <= 0 || imageHeight <= 0)
+        {
+            return;
+        }
+
+        const double world = StarSystemDocStore.WorldSize;
+        var fit = Math.Min(world / imageWidth, world / imageHeight);
+        var drawWidth = imageWidth * fit;
+        var drawHeight = imageHeight * fit;
+        var originX = (world - drawWidth) / 2;
+        var originY = (world - drawHeight) / 2;
+
+        canvas.DrawImage(BackgroundImage,
+            (float)(originX * Scale + OffsetX),
+            (float)(originY * Scale + OffsetY),
+            (float)(drawWidth * Scale),
+            (float)(drawHeight * Scale));
+    }
+
     public static Color ColorForOwner(string owner) => owner switch
     {
         "The Eden Accord" => Color.FromArgb("#10b981"),