#158 new: follow system color

lib/view/widget/color_picker.dart

@@ -0,0 +1,77 @@
+import 'package:flutter/material.dart';
+
+enum _ColorPropType {
+  r,
+  g,
+  b,
+}
+
+class ColorPicker extends StatefulWidget {
+  final Color color;
+  final ValueChanged<Color> onColorChanged;
+
+  const ColorPicker({
+    super.key,
+    required this.color,
+    required this.onColorChanged,
+  });
+
+  @override
+  _ColorPickerState createState() => _ColorPickerState();
+}
+
+class _ColorPickerState extends State<ColorPicker> {
+  late int _r = widget.color.red;
+  late int _g = widget.color.green;
+  late int _b = widget.color.blue;
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      children: [
+        _buildProgress(_ColorPropType.r, 'R', _r.toDouble()),
+        _buildProgress(_ColorPropType.g, 'G', _g.toDouble()),
+        _buildProgress(_ColorPropType.b, 'B', _b.toDouble()),
+      ],
+    );
+  }
+
+  Widget _buildProgress(_ColorPropType type, String title, double value) {
+    return Row(
+      children: [
+        Text(
+          title,
+          style: const TextStyle(
+            fontSize: 16,
+            fontWeight: FontWeight.bold,
+          ),
+        ),
+        Expanded(
+          child: Slider(
+            value: value,
+            onChanged: (v) {
+              setState(() {
+                switch (type) {
+                  case _ColorPropType.r:
+                    _r = v.toInt();
+                    break;
+                  case _ColorPropType.g:
+                    _g = v.toInt();
+                    break;
+                  case _ColorPropType.b:
+                    _b = v.toInt();
+                    break;
+                }
+              });
+              widget.onColorChanged(Color.fromARGB(255, _r, _g, _b));
+            },
+            min: 0,
+            max: 255,
+            divisions: 255,
+            label: value.toInt().toString(),
+          ),
+        ),
+      ],
+    );
+  }
+}