feat: писюльки прыгают

test/spectrum_background_test.dart

@@ -0,0 +1,199 @@
+import 'dart:typed_data';
+import 'dart:ui' as ui;
+
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+import 'package:komet/core/config/app_spectrum_background.dart';
+import 'package:komet/frontend/widgets/komet_avatar.dart';
+import 'package:komet/frontend/widgets/spectrum_background.dart';
+
+class _CountingCanvas implements Canvas {
+  final List<Rect> rects = <Rect>[];
+  final List<Color> colors = <Color>[];
+
+  @override
+  void drawRect(Rect rect, Paint paint) {
+    rects.add(rect);
+    colors.add(paint.color);
+  }
+
+  @override
+  dynamic noSuchMethod(Invocation invocation) => null;
+}
+
+const Size _viewport = Size(800, 600);
+
+Widget _host({Widget? overlay, required Brightness brightness, Color? seed}) {
+  return MaterialApp(
+    theme: ThemeData(
+      colorScheme: ColorScheme.fromSeed(
+        seedColor: seed ?? const Color(0xFF6750A4),
+        brightness: brightness,
+      ),
+    ),
+    home: Scaffold(
+      body: Stack(
+        children: [
+          const Positioned.fill(child: SpectrumBackground()),
+          ?overlay,
+        ],
+      ),
+    ),
+  );
+}
+
+_CountingCanvas _paintOnce(WidgetTester tester) {
+  final paint = tester.widget<CustomPaint>(
+    find.descendant(
+      of: find.byType(SpectrumBackground),
+      matching: find.byType(CustomPaint),
+    ),
+  );
+  final canvas = _CountingCanvas();
+  paint.painter!.paint(canvas, _viewport);
+  return canvas;
+}
+
+Future<ByteData> _renderedPixels(WidgetTester tester) async {
+  final paint = tester.widget<CustomPaint>(
+    find.descendant(
+      of: find.byType(SpectrumBackground),
+      matching: find.byType(CustomPaint),
+    ),
+  );
+  final recorder = ui.PictureRecorder();
+  paint.painter!.paint(Canvas(recorder), _viewport);
+  final picture = recorder.endRecording();
+
+  ByteData? data;
+  await tester.runAsync(() async {
+    final image = await picture.toImage(
+      _viewport.width.round(),
+      _viewport.height.round(),
+    );
+    data = await image.toByteData(format: ui.ImageByteFormat.rawRgba);
+    image.dispose();
+  });
+  return data!;
+}
+
+double _averageRed(ByteData pixels, int row, int fromX, int toX) {
+  var total = 0.0;
+  var counted = 0;
+  for (var x = fromX; x < toX; x++) {
+    final offset = (row * _viewport.width.round() + x) * 4;
+    if (pixels.getUint8(offset + 3) == 0) continue;
+    total += pixels.getUint8(offset);
+    counted++;
+  }
+  return counted == 0 ? 0 : total / counted;
+}
+
+Future<void> _settleBars(WidgetTester tester) async {
+  for (var i = 0; i < 12; i++) {
+    await tester.pump(const Duration(milliseconds: 60));
+  }
+}
+
+void main() {
+  setUp(() async {
+    SharedPreferences.setMockInitialValues(<String, Object>{
+      AppSpectrumBackground.prefKey: true,
+    });
+    await AppSpectrumBackground.load();
+  });
+
+  testWidgets('bars grow from the bottom and stay inside the lower zone', (
+    tester,
+  ) async {
+    await tester.pumpWidget(_host(brightness: Brightness.dark));
+    await _settleBars(tester);
+
+    final canvas = _paintOnce(tester);
+    expect(canvas.rects, isNotEmpty);
+
+    final zoneTop = _viewport.height * (1 - SpectrumTuning.heightFraction);
+    for (final rect in canvas.rects) {
+      expect(rect.bottom, _viewport.height);
+      expect(rect.top, greaterThanOrEqualTo(zoneTop - 0.01));
+      expect(rect.width, SpectrumTuning.barWidth);
+    }
+
+    final heights = canvas.rects.map((r) => r.height).toSet();
+    expect(heights.length, greaterThan(1));
+  });
+
+  testWidgets('bar color is a neutral lift of the surface, not the accent', (
+    tester,
+  ) async {
+    await tester.pumpWidget(
+      _host(brightness: Brightness.dark, seed: const Color(0xFFFF4FA3)),
+    );
+    await _settleBars(tester);
+
+    final context = tester.element(find.byType(SpectrumBackground));
+    final cs = Theme.of(context).colorScheme;
+    final bar = _paintOnce(tester).colors.first;
+
+    expect(bar.computeLuminance(), greaterThan(cs.surface.computeLuminance()));
+    expect(
+      bar.computeLuminance(),
+      lessThan(cs.surfaceContainerHighest.computeLuminance()),
+    );
+
+    final barHsl = HSLColor.fromColor(bar);
+    final surfaceHsl = HSLColor.fromColor(cs.surface);
+    expect(barHsl.saturation, lessThanOrEqualTo(surfaceHsl.saturation + 0.01));
+    expect((barHsl.hue - surfaceHsl.hue).abs(), lessThan(1));
+    expect(barHsl.lightness, greaterThan(surfaceHsl.lightness));
+  });
+
+  testWidgets('bar count scales to thin lines across the width', (
+    tester,
+  ) async {
+    await tester.pumpWidget(_host(brightness: Brightness.dark));
+    await _settleBars(tester);
+
+    final expected =
+        (_viewport.width + SpectrumTuning.barGap) /
+        (SpectrumTuning.barWidth + SpectrumTuning.barGap);
+    expect(expected, greaterThan(400));
+    expect(_paintOnce(tester).rects.length, greaterThan(200));
+  });
+
+  testWidgets('a nearby avatar tints the bars closest to it', (tester) async {
+    await tester.pumpWidget(
+      _host(
+        brightness: Brightness.dark,
+        overlay: const Align(
+          alignment: Alignment.bottomLeft,
+          child: KometAvatar(
+            name: 'Nova',
+            size: 48,
+            backgroundColor: Color(0xFFFF0000),
+            fadeIn: false,
+          ),
+        ),
+      ),
+    );
+    await _settleBars(tester);
+
+    final pixels = await _renderedPixels(tester);
+    final row = _viewport.height.round() - 2;
+    final nearAvatar = _averageRed(pixels, row, 0, 200);
+    final farSide = _averageRed(pixels, row, 600, 800);
+
+    expect(nearAvatar, greaterThan(farSide));
+  });
+
+  testWidgets('no tint sources leave every bar on the base color', (
+    tester,
+  ) async {
+    await tester.pumpWidget(_host(brightness: Brightness.dark));
+    await _settleBars(tester);
+
+    expect(_paintOnce(tester).colors.toSet().length, 1);
+  });
+}