SignalPainterWidget

A high-performance, leaf render-object widget driven by a double progress signal.

SignalPainterWidget bypasses the entire widget build and layout phases, subscribing directly to a progress signal and rendering on the canvas. When progress updates, only the GPU paint phase is run.

Example#

final progress = signal(0.0);

@override
Widget build(BuildContext context) {
  return SignalPainterWidget(
    progress: progress,
    painter: (canvas, size, value) {
      final paint = Paint()
        ..color = Colors.blue
        ..style = PaintingStyle.stroke
        ..strokeWidth = 4.0;
      canvas.drawCircle(
        Offset(size.width / 2, size.height / 2),
        value * 50.0,
        paint,
      );
    },
  );
}

Constructors#

View Constructors

`SignalPainterWidget({super.key, required this.progress, required this.painter})`

Creates a new SignalPainterWidget.

Properties#

View Properties

`core.ReadonlySignal progress`

The progress signal whose value will be passed to painter.

`void Function(Canvas canvas, Size size, double value) painter`

The custom painting callback function.

Methods#

View Methods