Add theme system for customizable backgrounds

- Move backgrounds to themed folders (backgrounds/desert/, backgrounds/custom/)
- Add theme config option in config.json (default: "desert")
- Add /api/config endpoint to serve theme and location
- Update pixel-view.js to load backgrounds from theme folder
- Add config.json.example for reference
- Update CONFIG.md documentation

Users can now set "theme": "custom" and place their own backgrounds
in backgrounds/custom/ to customize the view for their location.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CONFIG.md

@@ -15,7 +15,8 @@ Edit `config.json` to customize your installation:
     "lat": 0.0,
     "lon": 0.0
   },
-  "web_port": 2001
+  "web_port": 2001,
+  "theme": "desert"
 }
 ```
 
@@ -31,6 +32,7 @@ Edit `config.json` to customize your installation:
 | `location.lat` | number | Latitude of your receiver location |
 | `location.lon` | number | Longitude of your receiver location |
 | `web_port` | number | Port for the web interface (default: 2001) |
+| `theme` | string | Background theme: `"desert"` (default) or `"custom"` |
 
 ### Receiver Configuration Examples
 
@@ -51,12 +53,44 @@ Edit `config.json` to customize your installation:
 
 ---
 
-## Background Images
+## Background Themes
 
-Pixel View uses directional background images to show the horizon view from your receiver location. You should customize these to match your actual surroundings.
+Pixel View uses directional background images to show the horizon view from your receiver location. Backgrounds are organized into themes stored in the `backgrounds/` folder.
+
+### Available Themes
+
+| Theme | Description |
+|-------|-------------|
+| `desert` | Las Vegas desert landscape (default) |
+| `custom` | Your own custom backgrounds |
+
+### Theme Folder Structure
+
+```
+backgrounds/
+├── desert/          # Default desert theme
+│   ├── north.png
+│   ├── east.png
+│   ├── south.png
+│   └── west.png
+└── custom/          # Your custom backgrounds
+    ├── README.md    # Instructions for creating custom backgrounds
+    ├── north.png
+    ├── east.png
+    ├── south.png
+    └── west.png
+```
+
+### Using Custom Backgrounds
+
+1. Add your background images to `backgrounds/custom/`
+2. Set `"theme": "custom"` in your `config.json`
+3. Restart the server
 
 ### Image Files
 
+Each theme folder needs these 4 directional images:
+
 | File | Direction | Description |
 |------|-----------|-------------|
 | `north.png` | North (0°) | View looking north from your location |

backgrounds/custom/README.md

@@ -0,0 +1,35 @@
+# Custom Backgrounds
+
+Place your custom background images in this folder.
+
+## Required Files
+
+You need to provide 4 directional background images:
+- `north.png` - View looking north
+- `east.png` - View looking east
+- `south.png` - View looking south
+- `west.png` - View looking west
+
+## Image Specifications
+
+- **Dimensions:** 1536 x 1024 pixels
+- **Format:** PNG with transparency support
+- **Orientation:** Each image should show the horizon/landscape as seen when facing that cardinal direction from your location
+
+## Tips
+
+- Include a horizon line in each image - the sun and moon will set behind it
+- Keep the upper portion (sky area) relatively simple for aircraft visibility
+- The bottom portion can have more detail (terrain, buildings, etc.)
+- Consider your local landmarks and terrain for each direction
+
+## Enabling Custom Theme
+
+Set the theme in `config.json`:
+```json
+{
+  "theme": "custom"
+}
+```
+
+Then restart the server.

config.json

@@ -6,5 +6,6 @@
     "lat": 0.0,
     "lon": 0.0
   },
-  "web_port": 2001
+  "web_port": 2001,
+  "theme": "desert"
 }

config.json.example

@@ -0,0 +1,11 @@
+{
+  "receivers": "AUTO",
+  "receiver_port": 30003,
+  "location": {
+    "name": "My Location",
+    "lat": 0.0,
+    "lon": 0.0
+  },
+  "web_port": 2001,
+  "theme": "desert"
+}

pixel-view.js

@@ -65,6 +65,9 @@ class PixelADSB {
         this.viewDirectionNames = { 0: 'N', 90: 'E', 180: 'S', 270: 'W' };
         this.fieldOfView = 90; // 90 degree field of view
 
+        // Theme for background images (loaded from config)
+        this.theme = 'desert';
+
         // Hover and selection tracking
         this.mouseX = -1;
         this.mouseY = -1;
@@ -109,7 +112,7 @@ class PixelADSB {
         });
 
         // Load environment images (directional backgrounds, base, sun, clouds)
-        // Directional background images
+        // Directional background images (loaded after fetching config)
         this.backgroundImages = {
             0: new Image(),    // North
             90: new Image(),   // East
@@ -118,24 +121,6 @@ class PixelADSB {
         };
         this.backgroundImagesLoaded = { 0: false, 90: false, 180: false, 270: false };
 
-        // Load directional backgrounds (fallback to desert.png if not available)
-        const directions = [
-            { deg: 0, name: 'north' },
-            { deg: 90, name: 'east' },
-            { deg: 180, name: 'south' },
-            { deg: 270, name: 'west' }
-        ];
-        directions.forEach(dir => {
-            this.backgroundImages[dir.deg].onload = () => {
-                this.backgroundImagesLoaded[dir.deg] = true;
-                console.log(`${dir.name}.png loaded`);
-            };
-            this.backgroundImages[dir.deg].onerror = () => {
-                console.warn(`Failed to load ${dir.name}.png, using fallback`);
-            };
-            this.backgroundImages[dir.deg].src = `${dir.name}.png?v=1`;
-        });
-
         this.sunImage = new Image();
         this.sunImage.onload = () => {
             this.sunImageLoaded = true;
@@ -410,8 +395,11 @@ class PixelADSB {
     }
 
     async init() {
-        // Fetch receiver location
+        // Fetch config (includes theme and location)
-        await this.fetchReceiverLocation();
+        await this.fetchConfig();
+
+        // Load background images based on theme
+        this.loadBackgroundImages();
 
         // Fetch weather
         await this.fetchWeather();
@@ -547,6 +535,41 @@ class PixelADSB {
         return padding + (normalizedAngle * usableWidth);
     }
 
+    async fetchConfig() {
+        try {
+            const response = await fetch('/api/config');
+            const data = await response.json();
+            this.theme = data.theme || 'desert';
+            this.receiverLat = data.location?.lat || 0;
+            this.receiverLon = data.location?.lon || 0;
+            this.locationName = data.location?.name || 'My Location';
+            console.log(`Config loaded - Theme: ${this.theme}, Location: ${this.locationName} (${this.receiverLat}, ${this.receiverLon})`);
+        } catch (error) {
+            console.warn('Could not fetch config, using defaults');
+            // Fallback to receiver-location API for backwards compatibility
+            await this.fetchReceiverLocation();
+        }
+    }
+
+    loadBackgroundImages() {
+        const directions = [
+            { deg: 0, name: 'north' },
+            { deg: 90, name: 'east' },
+            { deg: 180, name: 'south' },
+            { deg: 270, name: 'west' }
+        ];
+        directions.forEach(dir => {
+            this.backgroundImages[dir.deg].onload = () => {
+                this.backgroundImagesLoaded[dir.deg] = true;
+                console.log(`${this.theme}/${dir.name}.png loaded`);
+            };
+            this.backgroundImages[dir.deg].onerror = () => {
+                console.warn(`Failed to load backgrounds/${this.theme}/${dir.name}.png`);
+            };
+            this.backgroundImages[dir.deg].src = `backgrounds/${this.theme}/${dir.name}.png?v=1`;
+        });
+    }
+
     async fetchReceiverLocation() {
         try {
             // Fetch from same server that serves pixel-view

server.py

@@ -24,7 +24,8 @@ config = {
         "lat": 0.0,
         "lon": 0.0
     },
-    "web_port": 2001
+    "web_port": 2001,
+    "theme": "desert"
 }
 
 def load_config():
@@ -45,6 +46,7 @@ def load_config():
     print(f"  Receiver port: {config['receiver_port']}")
     print(f"  Location: {config['location']['name']} ({config['location']['lat']}, {config['location']['lon']})")
     print(f"  Web port: {config['web_port']}")
+    print(f"  Theme: {config.get('theme', 'desert')}")
 
 # Flight data storage
 flights: Dict[str, dict] = {}
@@ -302,6 +304,13 @@ async def handle_receiver_location(request):
         "name": config["location"]["name"]
     })
 
+async def handle_config(request):
+    """Return client-relevant configuration"""
+    return web.json_response({
+        "theme": config.get("theme", "desert"),
+        "location": config["location"]
+    })
+
 async def handle_http(request):
     """Serve static files"""
     path = request.path
@@ -319,6 +328,7 @@ async def start_http_server():
     app = web.Application()
     app.router.add_get('/ws', websocket_handler)
     app.router.add_get('/api/receiver-location', handle_receiver_location)
+    app.router.add_get('/api/config', handle_config)
     app.router.add_get('/{tail:.*}', handle_http)
 
     runner = web.AppRunner(app)