Canvas Scroll Flutter

canva_scroll.dart

     import 'package:flutter/material.dart';

      class myscroll extends statelesswidget {
        @override
        widget build(buildcontext context) {
          return new materialapp(
            title: 'flutter demo',
            theme: new themedata(
              primaryswatch: colors.blue,
            ),
            home: new myhomepage(title: 'canvas scroller'),
          );
        }
      }
      class myhomepage extends statefulwidget {
        myhomepage({key key, this.title}) : super(key: key);
        final string title;

        @override
        _myhomepagestate createstate() => new _myhomepagestate();
      }
      class _myhomepagestate extends state<myhomepage> {
        @override
        widget build(buildcontext context) {
          final width = mediaquery.of(context).size.width;
          final height = mediaquery.of(context).size.height;
          return new scaffold(
            appbar: new appbar(
              title: new text(widget.title),
            ),
            body: new center(
              child: new singlechildscrollview(
                scrolldirection: axis.horizontal,
                child: new custompaint(
                  painter: new mycanvasview(),
                  size: new size(width*2, height/2),
                ),
              ),
            ),
          );
        }
      }

      class mycanvasview extends custompainter{
        @override
        void paint(canvas canvas, size size) {
          var paint = new paint();
          paint..shader = new lineargradient(colors: [colors.yellow[700], colors.redaccent],
             begin: alignment.centerright, end: alignment.centerleft).createshader(new offset(0.0, 0.0)&size);
          canvas.drawrect(new offset(0.0, 0.0)&size, paint);
          var path = new path();
          path.moveto(0.0, size.height);
          path.lineto(1*size.width/4, 0*size.height/4);
          path.lineto(2*size.width/4, 2*size.height/4);
          path.lineto(3*size.width/4, 0*size.height/4);
          path.lineto(4*size.width/4, 4*size.height/4);
          canvas.drawpath(path, new paint()..color = colors.yellow ..strokewidth = 4.0 .. style = paintingstyle.stroke);
        }

        @override
        bool shouldrepaint(custompainter olddelegate) {
          return false;
        }

      }