feat: кастомные обои чата (SVG-паттерны, темы, глобальный фон, прозрачные панели)

lib/core/utils/tiled_svg.dart

@@ -0,0 +1,134 @@
+import 'dart:ui' as ui;
+
+import 'package:flutter/material.dart';
+import 'package:flutter_svg/flutter_svg.dart';
+
+class TiledSvgPattern extends StatefulWidget {
+  final String asset;
+  final Color color;
+  final double opacity;
+  final double tileSize;
+
+  const TiledSvgPattern({
+    super.key,
+    required this.asset,
+    required this.color,
+    this.opacity = 0.12,
+    this.tileSize = 120,
+  });
+
+  @override
+  State<TiledSvgPattern> createState() => _TiledSvgPatternState();
+}
+
+class _TiledSvgPatternState extends State<TiledSvgPattern> {
+  static final Map<String, ui.Image> _cache = {};
+  static final Map<String, Future<ui.Image>> _pending = {};
+
+  ui.Image? _image;
+  double _dpr = 1;
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    final dpr = MediaQuery.maybeOf(context)?.devicePixelRatio ?? 1;
+    if (dpr != _dpr || _image == null) {
+      _dpr = dpr;
+      _resolve();
+    }
+  }
+
+  @override
+  void didUpdateWidget(TiledSvgPattern old) {
+    super.didUpdateWidget(old);
+    if (old.asset != widget.asset || old.tileSize != widget.tileSize) {
+      _resolve();
+    }
+  }
+
+  Future<void> _resolve() async {
+    final px = (widget.tileSize * _dpr).clamp(1, 4096).round();
+    final key = '${widget.asset}@$px';
+    final cached = _cache[key];
+    if (cached != null) {
+      if (_image != cached) setState(() => _image = cached);
+      return;
+    }
+    final future = _pending.putIfAbsent(key, () => _rasterize(widget.asset, px));
+    try {
+      final image = await future;
+      _cache[key] = image;
+      _pending.remove(key);
+      if (mounted) setState(() => _image = image);
+    } catch (_) {
+      _pending.remove(key);
+    }
+  }
+
+  static Future<ui.Image> _rasterize(String asset, int px) async {
+    final info = await vg.loadPicture(SvgAssetLoader(asset), null);
+    final recorder = ui.PictureRecorder();
+    final canvas = Canvas(recorder);
+    final size = info.size;
+    if (size.width > 0 && size.height > 0) {
+      canvas.scale(px / size.width, px / size.height);
+    }
+    canvas.drawPicture(info.picture);
+    final picture = recorder.endRecording();
+    final image = await picture.toImage(px, px);
+    info.picture.dispose();
+    picture.dispose();
+    return image;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final image = _image;
+    if (image == null) return const SizedBox.expand();
+    return CustomPaint(
+      size: Size.infinite,
+      painter: _PatternPainter(
+        image: image,
+        color: widget.color.withValues(alpha: widget.opacity),
+        tileSize: widget.tileSize,
+        dpr: _dpr,
+      ),
+    );
+  }
+}
+
+class _PatternPainter extends CustomPainter {
+  final ui.Image image;
+  final Color color;
+  final double tileSize;
+  final double dpr;
+
+  const _PatternPainter({
+    required this.image,
+    required this.color,
+    required this.tileSize,
+    required this.dpr,
+  });
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    final s = 1 / dpr;
+    final matrix = Matrix4.identity()..scaleByDouble(s, s, 1, 1);
+    final paint = Paint()
+      ..shader = ImageShader(
+        image,
+        TileMode.repeated,
+        TileMode.repeated,
+        matrix.storage,
+      )
+      ..colorFilter = ColorFilter.mode(color, BlendMode.srcIn);
+    canvas.drawRect(Offset.zero & size, paint);
+  }
+
+  @override
+  bool shouldRepaint(_PatternPainter old) =>
+      old.image != image ||
+      old.color != color ||
+      old.tileSize != tileSize ||
+      old.dpr != dpr;
+}

lib/core/utils/wallpaper_seed.dart

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+import 'dart:io';
+
+import 'package:flutter/material.dart';
+import 'package:image/image.dart' as img;
+
+import '../config/chat_wallpaper_themes.dart';
+import '../storage/chat_wallpaper_store.dart';
+
+Future<Color?> computeWallpaperSeed(ChatWallpaper? wallpaper) async {
+  if (wallpaper == null) return null;
+  if (!wallpaper.isImage) {
+    final theme = chatWallpaperThemeById(wallpaper.themeId);
+    if (theme == null) return null;
+    return _mostVivid(theme.colors);
+  }
+  final path = wallpaper.imagePath;
+  if (path == null) return null;
+  try {
+    final bytes = await File(path).readAsBytes();
+    final decoded = img.decodeImage(bytes);
+    if (decoded == null) return null;
+    final small = img.copyResize(decoded, width: 8, height: 8);
+    var r = 0, g = 0, b = 0, n = 0;
+    for (final pixel in small) {
+      r += pixel.r.toInt();
+      g += pixel.g.toInt();
+      b += pixel.b.toInt();
+      n++;
+    }
+    if (n == 0) return null;
+    return Color.fromARGB(255, r ~/ n, g ~/ n, b ~/ n);
+  } catch (_) {
+    return null;
+  }
+}
+
+Color _mostVivid(List<Color> colors) {
+  var best = colors.first;
+  var bestScore = -1.0;
+  for (final color in colors) {
+    final hsl = HSLColor.fromColor(color);
+    final score = hsl.saturation * (1 - (hsl.lightness - 0.5).abs());
+    if (score > bestScore) {
+      bestScore = score;
+      best = color;
+    }
+  }
+  return best;
+}