Merge pull request #23 from robiness/offset-field-configurator

Introduce `OffsetFieldConfigurator`

lib/src/field_configurators/offset_field_configurator.dart

@@ -0,0 +1,120 @@
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:stage_craft/stage_craft.dart';
+
+/// Represents a offset parameter for a widget on a [WidgetStage].
+class OffsetFieldConfigurator extends FieldConfigurator<Offset> {
+  OffsetFieldConfigurator({
+    required super.value,
+    required super.name,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return OffsetFieldConfigurationWidget(
+      configurator: this,
+      updateValue: (value) {
+        updateValue(value ?? Offset.zero);
+      },
+    );
+  }
+}
+
+class OffsetFieldConfigurationWidget extends StatefulConfigurationWidget<Offset?> {
+  const OffsetFieldConfigurationWidget({
+    super.key,
+    required super.configurator,
+    required super.updateValue,
+  });
+
+  @override
+  State<OffsetFieldConfigurationWidget> createState() => _OffsetFieldConfigurationWidgetState();
+}
+
+class _OffsetFieldConfigurationWidgetState extends State<OffsetFieldConfigurationWidget> {
+  late final TextEditingController _xController;
+  late final TextEditingController _yController;
+
+  @override
+  void initState() {
+    _xController = TextEditingController(
+      text: widget.configurator.value?.dx.toString(),
+    );
+    _yController = TextEditingController(
+      text: widget.configurator.value?.dy.toString(),
+    );
+    widget.configurator.addListener(() {
+      if (widget.configurator.value == null) {
+        _xController.text = '';
+        _yController.text = '';
+      }
+    });
+    super.initState();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      children: [
+        Row(
+          children: [
+            const Text('x'),
+            const SizedBox(width: 8),
+            _OffsetTextField(
+              controller: _xController,
+              onChanged: (value) {
+                widget.updateValue(
+                  Offset(
+                    double.tryParse(value) ?? 0.0,
+                    widget.configurator.value!.dy,
+                  ),
+                );
+              },
+            ),
+            const SizedBox(width: 16),
+            const Text('y'),
+            const SizedBox(width: 8),
+            _OffsetTextField(
+              controller: _yController,
+              onChanged: (value) {
+                widget.updateValue(
+                  Offset(
+                    widget.configurator.value!.dx,
+                    double.tryParse(value) ?? 0.0,
+                  ),
+                );
+              },
+            ),
+          ],
+        ),
+      ],
+    );
+  }
+}
+
+class _OffsetTextField extends StatelessWidget {
+  const _OffsetTextField({
+    required this.controller,
+    this.onChanged,
+  });
+
+  final TextEditingController controller;
+  final Function(String)? onChanged;
+
+  @override
+  Widget build(BuildContext context) {
+    return SizedBox(
+      width: 50,
+      child: FieldConfiguratorInputField(
+        controller: controller,
+        inputFormatters: [
+          FilteringTextInputFormatter.allow(RegExp('-?[0-9.,]')),
+        ],
+        onChanged: (value) {
+          final replacedComma = value.replaceAll(',', '.');
+          onChanged?.call(replacedComma);
+        },
+      ),
+    );
+  }
+}