Configure navgrid node and field size through GUI (#478)

* edit navgrid attributes

* update default navgrid to use 0.3m node size

* update navgrid page tests

lib/pages/nav_grid_page.dart

@@ -3,10 +3,12 @@ import 'dart:math';
 
 import 'package:file/file.dart';
 import 'package:flutter/material.dart';
+import 'package:function_tree/function_tree.dart';
 import 'package:path/path.dart';
 import 'package:pathplanner/pathfinding/nav_grid.dart';
 import 'package:pathplanner/widgets/field_image.dart';
 import 'package:pathplanner/util/path_painter_util.dart';
+import 'package:pathplanner/widgets/number_text_field.dart';
 
 class NavGridPage extends StatefulWidget {
   final Directory deployDirectory;
@@ -130,10 +132,121 @@ class _NavGridPageState extends State<NavGridPage> {
             ),
           ),
         ),
+        Align(
+          alignment: Alignment.bottomRight,
+          child: Padding(
+            padding: const EdgeInsets.all(16.0),
+            child: FloatingActionButton.extended(
+              label: const Text('Edit Grid'),
+              icon: const Icon(Icons.edit),
+              onPressed: _showEditDialog,
+            ),
+          ),
+        ),
       ],
     );
   }
 
+  void _showEditDialog() {
+    TextEditingController nodeSizeController = TextEditingController();
+    TextEditingController fieldLengthController = TextEditingController();
+    TextEditingController fieldWidthController = TextEditingController();
+
+    showDialog(
+      context: this.context,
+      builder: (context) {
+        return AlertDialog(
+          title: const Text('Edit Grid'),
+          content: SizedBox(
+            width: 350,
+            child: Column(
+              mainAxisSize: MainAxisSize.min,
+              crossAxisAlignment: CrossAxisAlignment.start,
+              children: [
+                Row(
+                  children: [
+                    Expanded(
+                        child: NumberTextField(
+                      initialText: _grid.nodeSizeMeters.toStringAsFixed(2),
+                      label: 'Node Size (M)',
+                      arrowKeyIncrement: 0.05,
+                      controller: nodeSizeController,
+                    )),
+                  ],
+                ),
+                const Text(
+                    'Larger node size = more performance, but less accuracy'),
+                const SizedBox(height: 16),
+                Row(
+                  children: [
+                    Expanded(
+                        child: NumberTextField(
+                      initialText: _grid.fieldSize.width.toStringAsFixed(2),
+                      label: 'Field Length (M)',
+                      arrowKeyIncrement: 0.01,
+                      controller: fieldLengthController,
+                    )),
+                    const SizedBox(width: 8),
+                    Expanded(
+                        child: NumberTextField(
+                      initialText: _grid.fieldSize.height.toStringAsFixed(2),
+                      label: 'Field Width (M)',
+                      arrowKeyIncrement: 0.01,
+                      controller: fieldWidthController,
+                    )),
+                  ],
+                ),
+                const SizedBox(height: 32),
+                const Text(
+                    'Note: Changing these attributes will clear the navgrid. This cannot be undone.'),
+              ],
+            ),
+          ),
+          actions: [
+            TextButton(
+              onPressed: () async {
+                String fileContent = await DefaultAssetBundle.of(this.context)
+                    .loadString('resources/default_navgrid.json');
+
+                setState(() {
+                  _grid = NavGrid.fromJson(jsonDecode(fileContent));
+                });
+                _saveNavGrid();
+
+                if (mounted) {
+                  Navigator.of(context).pop();
+                }
+              },
+              child: const Text('Restore Default'),
+            ),
+            TextButton(
+              onPressed: () {
+                if (nodeSizeController.text.isNotEmpty &&
+                    fieldLengthController.text.isNotEmpty &&
+                    fieldWidthController.text.isNotEmpty) {
+                  num nodeSize = nodeSizeController.text.interpret();
+                  num fieldLength = fieldLengthController.text.interpret();
+                  num fieldWidth = fieldWidthController.text.interpret();
+
+                  setState(() {
+                    _grid = NavGrid.blankGrid(
+                      nodeSizeMeters: nodeSize,
+                      fieldSize:
+                          Size(fieldLength.toDouble(), fieldWidth.toDouble()),
+                    );
+                  });
+                  _saveNavGrid();
+                  Navigator.of(context).pop();
+                }
+              },
+              child: const Text('Confirm'),
+            ),
+          ],
+        );
+      },
+    );
+  }
+
   double _xPixelsToMeters(double pixels) {
     return ((pixels - 48) / _NavigationPainter.scale) /
         widget.fieldImage.pixelsPerMeter;

lib/pathfinding/nav_grid.dart

@@ -14,6 +14,16 @@ class NavGrid {
     required this.grid,
   });
 
+  NavGrid.blankGrid({
+    required this.nodeSizeMeters,
+    required this.fieldSize,
+  }) : grid = [] {
+    int rows = (fieldSize.height / nodeSizeMeters).ceil();
+    int cols = (fieldSize.width / nodeSizeMeters).ceil();
+
+    grid = List.generate(rows, (index) => List.filled(cols, false));
+  }
+
   NavGrid.fromJson(Map<String, dynamic> json)
       : fieldSize = _sizeFromJson(json['field_size']),
         nodeSizeMeters = json['nodeSizeMeters'] ?? 0.2,

lib/widgets/number_text_field.dart

@@ -20,8 +20,10 @@ class NumberTextField extends StatelessWidget {
     this.onSubmitted,
     this.enabled = true,
     this.arrowKeyIncrement = 0.01,
+    TextEditingController? controller,
   }) {
-    _controller = _getController(initialText);
+    _controller = controller ?? TextEditingController();
+    _controller.text = initialText;
   }
 
   @override
@@ -114,10 +116,4 @@ class NumberTextField extends StatelessWidget {
       }
     }
   }
-
-  TextEditingController _getController(String text) {
-    return TextEditingController(text: text)
-      ..selection =
-          TextSelection.fromPosition(TextPosition(offset: text.length));
-  }
 }