WIP #212 Light card support

lib/plugins/circular_slider/slider_painter.dart

@@ -0,0 +1,77 @@
+import 'dart:math';
+
+import 'package:flutter/material.dart';
+
+import 'circular_slider_paint.dart' show CircularSliderMode;
+import 'utils.dart';
+
+class SliderPainter extends CustomPainter {
+  CircularSliderMode mode;
+  double startAngle;
+  double endAngle;
+  double sweepAngle;
+  Color selectionColor;
+  Color handlerColor;
+  double handlerOutterRadius;
+  bool showRoundedCapInSelection;
+  bool showHandlerOutter;
+  double sliderStrokeWidth;
+
+  Offset initHandler;
+  Offset endHandler;
+  Offset center;
+  double radius;
+
+  SliderPainter({
+    @required this.mode,
+    @required this.startAngle,
+    @required this.endAngle,
+    @required this.sweepAngle,
+    @required this.selectionColor,
+    @required this.handlerColor,
+    @required this.handlerOutterRadius,
+    @required this.showRoundedCapInSelection,
+    @required this.showHandlerOutter,
+    @required this.sliderStrokeWidth,
+  });
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    Paint progress = _getPaint(color: selectionColor);
+
+    center = Offset(size.width / 2, size.height / 2);
+    radius = min(size.width / 2, size.height / 2) - sliderStrokeWidth;
+
+    canvas.drawArc(Rect.fromCircle(center: center, radius: radius),
+        -pi / 2 + startAngle, sweepAngle, false, progress);
+
+    Paint handler = _getPaint(color: handlerColor, style: PaintingStyle.fill);
+    Paint handlerOutter = _getPaint(color: handlerColor, width: 2.0);
+
+    // draw handlers
+    if (mode == CircularSliderMode.doubleHandler) {
+      initHandler = radiansToCoordinates(center, -pi / 2 + startAngle, radius);
+      canvas.drawCircle(initHandler, 8.0, handler);
+      canvas.drawCircle(initHandler, handlerOutterRadius, handlerOutter);
+    }
+
+    endHandler = radiansToCoordinates(center, -pi / 2 + endAngle, radius);
+    canvas.drawCircle(endHandler, 8.0, handler);
+    if (showHandlerOutter) {
+      canvas.drawCircle(endHandler, handlerOutterRadius, handlerOutter);
+    }
+  }
+
+  Paint _getPaint({@required Color color, double width, PaintingStyle style}) =>
+      Paint()
+        ..color = color
+        ..strokeCap =
+        showRoundedCapInSelection ? StrokeCap.round : StrokeCap.butt
+        ..style = style ?? PaintingStyle.stroke
+        ..strokeWidth = width ?? sliderStrokeWidth;
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) {
+    return true;
+  }
+}