How to Make Widget Flutter Fast?-CodePudding

I'm trying to make my own photo codecs, I made a 512 * 512 image,

I'm just trying to build with one color and arrange in a Container in Column and Row My Code:

 SizedBox(
          height: 512,
          width: 512,
          child: Column(
            children: List.generate(512, (index) {
              return Row(
                children: List.generate(512, (index) {
                  return Container(
                    height: 1,
                    width: 1,
                    color: Colors.blue,
                  );
                }),
              );
            }),
          ),
        ),

I tried this code, it is very slow,

So how to build flutter widget fast?

CodePudding user response：

You have to use CustomPainter class to draw your own custom widget

CodePudding user response：

As said by powerman23rus said, you should use a CustomPainter, here's an example of implementation based on the code you've provided:

class ImageWidget extends StatelessWidget {
  final Color color;
  final Size size;

  const ImageWidget({
    super.key,
    this.color = Colors.blue,
    this.size = const Size(512, 512),
  });

  @override
  Widget build(BuildContext context) {
    return CustomPaint(
      painter: ImagePainter(color: color),
      size: size,
    );
  }
}

class ImagePainter extends CustomPainter {
  final Color color;

  ImagePainter({required this.color});

  @override
  void paint(Canvas canvas, Size size) {
    final paint = Paint()..color = color;
    canvas.drawRect(Offset.zero & size, paint);
  }

  @override
  bool shouldRepaint(ImagePainter oldDelegate) => false;
}

You can try the full example on DartPad to check by yourself the performance.