Add PageView benchmark (representative of full screen CustomPainter) (#69990)

dev/benchmarks/macrobenchmarks/lib/src/web/bench_pageview_scroll_linethrough.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+
+import 'recorder.dart';
+
+/// Creates a [PageView] that uses a font style that can't be rendered
+/// using canvas (switching to DOM).
+///
+/// Since the whole page uses a CustomPainter this is a good representation
+/// for apps that have pictures with large number of painting commands.
+class BenchPageViewScrollLineThrough extends WidgetRecorder {
+  BenchPageViewScrollLineThrough() : super(name: benchmarkName);
+
+  static const String benchmarkName = 'bench_page_view_scroll_line_through';
+
+  @override
+  Widget createWidget() => const MaterialApp(
+        title: 'PageView Scroll LineThrough Benchmark',
+        home: _MyScrollContainer(),
+      );
+}
+
+class _MyScrollContainer extends StatefulWidget {
+  const _MyScrollContainer({Key key}) : super(key: key);
+
+  @override
+  State<_MyScrollContainer> createState() => _MyScrollContainerState();
+}
+
+class _MyScrollContainerState extends State<_MyScrollContainer> {
+  static const Duration stepDuration = Duration(milliseconds: 500);
+
+  PageController pageController;
+  int pageNumber = 0;
+
+  @override
+  void initState() {
+    super.initState();
+
+    pageController = PageController();
+
+    // Without the timer the animation doesn't begin.
+    Timer.run(() async {
+      while (pageNumber < 25) {
+        await pageController.animateToPage(pageNumber % 5,
+            duration: stepDuration, curve: Curves.easeInOut);
+        pageNumber++;
+      }
+    });
+  }
+
+  @override
+  void dispose() {
+    super.dispose();
+    pageController.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return PageView.builder(
+        controller: pageController,
+        itemBuilder: (BuildContext context, int position) {
+          return CustomPaint(
+            painter: _CustomPainter('aa'),
+            size: const Size(300, 500),
+          );
+        });
+  }
+}
+
+class _CustomPainter extends CustomPainter {
+  _CustomPainter(this.text);
+
+  final String text;
+  Paint _linePainter;
+  TextPainter _textPainter;
+  static const double lineWidth = 0.5;
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    canvas.clipRect(Rect.fromLTWH(0, 0, size.width, size.height));
+    double xPosition, yPosition;
+    final double width = size.width / 7;
+    final double height = size.height / 6;
+    xPosition = 0;
+    const double viewPadding = 5;
+    const double circlePadding = 4;
+    yPosition = viewPadding;
+    _textPainter = _textPainter ?? TextPainter();
+    _textPainter.textDirection = TextDirection.ltr;
+    _textPainter.textWidthBasis = TextWidthBasis.longestLine;
+    _textPainter.textScaleFactor = 1;
+    const TextStyle textStyle =
+        TextStyle(color: Colors.black87, fontSize: 13, fontFamily: 'Roboto');
+
+    _linePainter = _linePainter ?? Paint();
+    _linePainter.isAntiAlias = true;
+    for (int i = 0; i < 42; i++) {
+      _linePainter.color = Colors.white;
+
+      TextStyle temp = textStyle;
+      if (i % 7 == 0) {
+        temp = textStyle.copyWith(decoration: TextDecoration.lineThrough);
+      }
+
+      final TextSpan span = TextSpan(
+        text: text,
+        style: temp,
+      );
+
+      _textPainter.text = span;
+
+      _textPainter.layout(minWidth: 0, maxWidth: width);
+      _linePainter.style = PaintingStyle.fill;
+      canvas.drawRect(
+          Rect.fromLTWH(xPosition, yPosition - viewPadding, width, height),
+          _linePainter);
+
+      _textPainter.paint(
+          canvas,
+          Offset(xPosition + (width / 2 - _textPainter.width / 2),
+              yPosition + circlePadding));
+      xPosition += width;
+      if (xPosition.round() >= size.width.round()) {
+        xPosition = 0;
+        yPosition += height;
+      }
+    }
+
+    _drawVerticalAndHorizontalLines(
+        canvas, size, yPosition, xPosition, height, width);
+  }
+
+  void _drawVerticalAndHorizontalLines(Canvas canvas, Size size,
+      double yPosition, double xPosition, double height, double width) {
+    yPosition = height;
+    _linePainter.strokeWidth = lineWidth;
+    _linePainter.color = Colors.grey;
+    canvas.drawLine(const Offset(0, lineWidth), Offset(size.width, lineWidth),
+        _linePainter);
+    for (int i = 0; i < 6; i++) {
+      canvas.drawLine(
+          Offset(0, yPosition), Offset(size.width, yPosition), _linePainter);
+      yPosition += height;
+    }
+
+    canvas.drawLine(Offset(0, size.height - lineWidth),
+        Offset(size.width, size.height - lineWidth), _linePainter);
+    xPosition = width;
+    canvas.drawLine(const Offset(lineWidth, 0), Offset(lineWidth, size.height),
+        _linePainter);
+    for (int i = 0; i < 6; i++) {
+      canvas.drawLine(
+          Offset(xPosition, 0), Offset(xPosition, size.height), _linePainter);
+      xPosition += width;
+    }
+  }
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) {
+    return true;
+  }
+}

dev/benchmarks/macrobenchmarks/lib/web_benchmarks.dart

@@ -20,6 +20,7 @@ import 'src/web/bench_dynamic_clip_on_static_picture.dart';
 import 'src/web/bench_mouse_region_grid_hover.dart';
 import 'src/web/bench_mouse_region_grid_scroll.dart';
 import 'src/web/bench_mouse_region_mixed_grid_hover.dart';
+import 'src/web/bench_pageview_scroll_linethrough.dart';
 import 'src/web/bench_paths.dart';
 import 'src/web/bench_picture_recording.dart';
 import 'src/web/bench_simple_lazy_text_scroll.dart';
@@ -46,6 +47,7 @@ final Map<String, RecorderFactory> benchmarks = <String, RecorderFactory>{
   BenchSimpleLazyTextScroll.benchmarkName: () => BenchSimpleLazyTextScroll(),
   BenchBuildMaterialCheckbox.benchmarkName: () => BenchBuildMaterialCheckbox(),
   BenchDynamicClipOnStaticPicture.benchmarkName: () => BenchDynamicClipOnStaticPicture(),
+  BenchPageViewScrollLineThrough.benchmarkName: () => BenchPageViewScrollLineThrough(),
   BenchPictureRecording.benchmarkName: () => BenchPictureRecording(),
   BenchUpdateManyChildLayers.benchmarkName: () => BenchUpdateManyChildLayers(),
   BenchMouseRegionGridScroll.benchmarkName: () => BenchMouseRegionGridScroll(),