WIP #212 Light card support

lib/plugins/circular_slider/base_painter.dart

@@ -0,0 +1,77 @@
+import 'dart:math';
+
+import 'package:flutter/material.dart';
+
+import 'utils.dart';
+
+class BasePainter extends CustomPainter {
+  Color baseColor;
+  Color selectionColor;
+  int primarySectors;
+  int secondarySectors;
+  double sliderStrokeWidth;
+
+  Offset center;
+  double radius;
+
+  BasePainter({
+    @required this.baseColor,
+    @required this.selectionColor,
+    @required this.primarySectors,
+    @required this.secondarySectors,
+    @required this.sliderStrokeWidth,
+  });
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    Paint base = _getPaint(color: baseColor);
+
+    center = Offset(size.width / 2, size.height / 2);
+    radius = min(size.width / 2, size.height / 2) - sliderStrokeWidth;
+    // we need this in the parent to calculate if the user clicks on the circumference
+
+    assert(radius > 0);
+
+    canvas.drawCircle(center, radius, base);
+
+    if (primarySectors > 0) {
+      _paintSectors(primarySectors, 8.0, selectionColor, canvas);
+    }
+
+    if (secondarySectors > 0) {
+      _paintSectors(secondarySectors, 6.0, baseColor, canvas);
+    }
+  }
+
+  void _paintSectors(
+      int sectors, double radiusPadding, Color color, Canvas canvas) {
+    Paint section = _getPaint(color: color, width: 2.0);
+
+    var endSectors =
+    getSectionsCoordinatesInCircle(center, radius + radiusPadding, sectors);
+    var initSectors =
+    getSectionsCoordinatesInCircle(center, radius - radiusPadding, sectors);
+    _paintLines(canvas, initSectors, endSectors, section);
+  }
+
+  void _paintLines(
+      Canvas canvas, List<Offset> inits, List<Offset> ends, Paint section) {
+    assert(inits.length == ends.length && inits.length > 0);
+
+    for (var i = 0; i < inits.length; i++) {
+      canvas.drawLine(inits[i], ends[i], section);
+    }
+  }
+
+  Paint _getPaint({@required Color color, double width, PaintingStyle style}) =>
+      Paint()
+        ..color = color
+        ..strokeCap = StrokeCap.round
+        ..style = style ?? PaintingStyle.stroke
+        ..strokeWidth = width ?? sliderStrokeWidth;
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) {
+    return false;
+  }
+}