Initial commit

lib/ui/cached_image.dart

@@ -0,0 +1,203 @@
+import 'package:flutter/material.dart';
+import 'package:palette_generator/palette_generator.dart';
+import 'package:path/path.dart' as p;
+import 'package:path_provider/path_provider.dart';
+import 'package:sqflite/sqflite.dart';
+import 'package:crypto/crypto.dart';
+import 'package:dio/dio.dart';
+
+import 'dart:io';
+import 'dart:convert';
+
+ImagesDatabase imagesDatabase = ImagesDatabase();
+
+class ImagesDatabase {
+
+  /*
+    images.db:
+    Table: images
+    Fields:
+      id - id
+      name - md5 hash of url. also filename
+      url - url
+      permanent - 0/1 - if image is cached or offline
+  */
+
+
+  Database db;
+  String imagesPath;
+
+  //Prepare database
+  Future init() async {
+    String dir = await getDatabasesPath();
+    String path = p.join(dir, 'images.db');
+    db = await openDatabase(
+      path,
+      version: 1,
+      singleInstance: false,
+      onCreate: (Database db, int version) async {
+        //Create table on db created
+        await db.execute('CREATE TABLE images (id INTEGER PRIMARY KEY, name TEXT, url TEXT, permanent INTEGER)');
+      }
+    );
+    //Prepare folders
+    imagesPath = p.join((await getApplicationDocumentsDirectory()).path, 'images/');
+    Directory imagesDir = Directory(imagesPath);
+    await imagesDir.create(recursive: true);
+  }
+
+  String getPath(String name) {
+    return p.join(imagesPath, name);
+  }
+
+  //Get image url/path, cache it
+  Future<String> getImage(String url, {bool permanent = false}) async {
+    //Already file
+    if (!url.startsWith('http')) {
+      url = url.replaceFirst('file://', '');
+      if (!permanent) return url;
+      //Update in db to permanent
+      String name = p.basenameWithoutExtension(url);
+      await db.rawUpdate('UPDATE images SET permanent == 1 WHERE name == ?', [name]);
+    }
+    //Filename = md5 hash
+    String hash = md5.convert(utf8.encode(url)).toString();
+    List<Map> results = await db.rawQuery('SELECT * FROM images WHERE name == ?', [hash]);
+    String path = getPath(hash);
+    if (results.length > 0) {
+      //Image in database
+      return path;
+    }
+    //Save image
+    Dio dio = Dio();
+    try {
+      await dio.download(url, path);
+      await db.insert('images', {'url': url, 'name': hash, 'permanent': permanent?1:0});
+      return path;
+    } catch (e) {
+      return null;
+    }
+  }
+
+  Future<PaletteGenerator> getPaletteGenerator(String url) async {
+    String path = await getImage(url);
+    //Get image provider
+    ImageProvider provider = AssetImage('assets/cover.jpg');
+    if (path != null) {
+      provider = FileImage(File(path));
+    }
+    PaletteGenerator paletteGenerator = await PaletteGenerator.fromImageProvider(provider);
+    return paletteGenerator;
+  }
+
+  //Get primary color from album art
+  Future<Color> getPrimaryColor(String url) async {
+    PaletteGenerator paletteGenerator = await getPaletteGenerator(url);
+    return paletteGenerator.colors.first;
+  }
+
+  //Check if is dark
+  Future<bool> isDark(String url) async {
+    PaletteGenerator paletteGenerator = await getPaletteGenerator(url);
+    return paletteGenerator.colors.first.computeLuminance() > 0.5 ? false : true;
+  }
+
+
+}
+
+class CachedImage extends StatefulWidget {
+
+  final String url;
+  final double width;
+  final double height;
+  final bool circular;
+
+  const CachedImage({Key key, this.url, this.height, this.width, this.circular = false}): super(key: key);
+
+  @override
+  _CachedImageState createState() => _CachedImageState();
+}
+
+class _CachedImageState extends State<CachedImage> {
+
+  final ImageProvider _placeholder = AssetImage('assets/cover.jpg');
+  ImageProvider _image = AssetImage('assets/cover.jpg');
+  double _opacity = 0.0;
+  bool _disposed = false;
+
+  Future<ImageProvider> _getImage() async {
+    //Image already path
+    if (!widget.url.startsWith('http')) {
+      //Remove file://, if used in audio_service
+      if (widget.url.startsWith('/')) return FileImage(File(widget.url));
+      return FileImage(File(widget.url.replaceFirst('file://', '')));
+    }
+    //Load image from db
+    String path = await imagesDatabase.getImage(widget.url);
+    if (path == null) return _placeholder;
+    return FileImage(File(path));
+  }
+
+  //Load image and fade
+  void _load() async {
+    ImageProvider image = await _getImage();
+    if (_disposed) return;
+    setState(() {
+      _image = image;
+      _opacity = 1.0;
+    });
+  }
+
+  @override
+  void dispose() {
+    _disposed = true;
+    super.dispose();
+  }
+
+  @override
+  void initState() {
+    _load();
+    super.initState();
+  }
+
+  @override
+  void didUpdateWidget(CachedImage oldWidget) {
+    _load();
+    super.didUpdateWidget(oldWidget);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Stack(
+      children: <Widget>[
+        widget.circular ?
+        CircleAvatar(
+          radius: (widget.width??widget.height),
+          backgroundImage: _placeholder,
+        ):
+        Image(
+          image: _placeholder,
+          height: widget.height,
+          width: widget.width,
+        ),
+        AnimatedOpacity(
+          duration: Duration(milliseconds: 250),
+          opacity: _opacity,
+          child: widget.circular ?
+          CircleAvatar(
+            radius: (widget.width??widget.height),
+            backgroundImage: _image,
+          ):
+          Image(
+            image: _image,
+            height: widget.height,
+            width: widget.width,
+          ),
+        )
+      ],
+    );
+  }
+
+}
+
+