app/lib/paegs/picture_display_page/picture_display_page.dart

import 'package:bbyyy/my_tools/AsperctRaioImage.dart';
import 'package:bbyyy/my_tools/my_views.dart';
import 'package:cached_network_image/cached_network_image.dart';
import 'package:flutter/material.dart';
import 'package:flutter_svg/svg.dart';

class PictureDisplayPage extends StatefulWidget {
  String imagePath;

  PictureDisplayPage(this.imagePath);

  @override
  _PictureDisplayPageState createState() => _PictureDisplayPageState();
}

class _PictureDisplayPageState extends State<PictureDisplayPage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.black,
      body: Column(
        children: <Widget>[
          Expanded(
            child: GestureDetector(
              child: AsperctRaioImage.network(widget.imagePath,
                  builder: (context, snapshot, url) {
                double h = (snapshot.data.height.toDouble() / 5);
                double w = (snapshot.data.width.toDouble() / 5);
                bool fw = h/w>=MediaQuery.of(context).size.height/MediaQuery.of(context).size.width;
                print('h-------------$h\nw----------------$w');
                return CachedNetworkImage(
                  imageUrl: widget.imagePath,
                  height: fw?h/w*MediaQuery.of(context).size.width:MediaQuery.of(context).size.height,
                  width: fw?MediaQuery.of(context).size.width:w/h*MediaQuery.of(context).size.height,
                );
              }),
              onTap: () {
                Navigator.pop(context);
              },
              behavior: HitTestBehavior.translucent,
            ),
          )
        ],
      ),
    );
  }
}