颤振：缩放自定义画家时性能低下

Question

我尝试在自定义画家上绘制许多TextSpan。一切正常，但是当我尝试缩放画家时，它变得非常慢。什么方式可以加快速度？

使用自定义绘画缩放小部件：

@override
Widget build(BuildContext context) {

return GestureTransformable(
    size: sz,
    initialScale: 0.3,
    maxScale: 40.0,
    minScale: 0.01,
    boundaryRect: Rect.fromLTWH(
      -sz.width * 10 / 2,
      -sz.height * 10 / 2,
      sz.width * 10,
      sz.height * 10,
    ),
    child: RepaintBoundary(
      child: CustomPaint(
        painter: CustomPaintSpans(),
      ),
    )
 );
}

和自定义画家：

@override
void paint(Canvas canvas, Size size) {

double delta = 10.0;
double pixelSize = 10.0;

for (int j = 0; j < 100; ++j) {
  for (int i = 0; i < 100; ++i) {

    double startX = delta + i * (pixelSize + 1);
    double startY = delta + j * (pixelSize + 1);

    ////////
    TextSpan textSpan = new TextSpan(
        text: "$i",
        style: TextStyle(fontSize: 1, color: Colors.grey, fontWeight: FontWeight.w800));
    TextPainter tp = TextPainter(
        textScaleFactor: 10,
        text: textSpan,
        textAlign: TextAlign.center,
        textDirection: TextDirection.ltr);
    tp.layout();
    Offset offset;
    offset = Offset(startX - pixelSize * 0.5, startY - pixelSize * 0.5);
    tp.paint(canvas, offset);
    ///////////
  }
}

performance app screen