packages/flutter/test/painting/paint_image_test.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:ui' as ui;

import 'package:flutter/foundation.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:flutter/painting.dart';

class TestCanvas implements Canvas {
  final List<Invocation> invocations = <Invocation>[];

  @override
  void noSuchMethod(Invocation invocation) {
    invocations.add(invocation);
  }
}

void main() {
  late ui.Image image300x300;
  late ui.Image image300x200;
  setUpAll(() async {
    image300x300 = await createTestImage(width: 300, height: 300, cache: false);
    image300x200 = await createTestImage(width: 300, height: 200, cache: false);
  });

  setUp(() {
    debugFlushLastFrameImageSizeInfo();
  });

  test('Cover and align', () async {
    final TestCanvas canvas = TestCanvas();
    paintImage(
      canvas: canvas,
      rect: const Rect.fromLTWH(50.0, 75.0, 200.0, 100.0),
      image: image300x300,
      fit: BoxFit.cover,
      alignment: const Alignment(-1.0, 0.0),
    );

    final Invocation command = canvas.invocations.firstWhere((Invocation invocation) {
      return invocation.memberName == #drawImageRect;
    });

    expect(command, isNotNull);
    expect(command.positionalArguments[0], equals(image300x300));
    expect(command.positionalArguments[1], equals(const Rect.fromLTWH(0.0, 75.0, 300.0, 150.0)));
    expect(command.positionalArguments[2], equals(const Rect.fromLTWH(50.0, 75.0, 200.0, 100.0)));
  });

  test('debugInvertOversizedImages', () async {
    debugInvertOversizedImages = true;
    final FlutterExceptionHandler? oldFlutterError = FlutterError.onError;

    final List<String> messages = <String>[];
    FlutterError.onError = (FlutterErrorDetails details) {
      messages.add(details.exceptionAsString());
    };

    final TestCanvas canvas = TestCanvas();
    const Rect rect = Rect.fromLTWH(50.0, 50.0, 200.0, 100.0);

    paintImage(
      canvas: canvas,
      rect: rect,
      image: image300x300,
      debugImageLabel: 'TestImage',
      fit: BoxFit.fill,
    );

    final List<Invocation> commands = canvas.invocations
      .skipWhile((Invocation invocation) => invocation.memberName != #saveLayer)
      .take(4)
      .toList();

    expect(commands[0].positionalArguments[0], rect);
    final Paint paint = commands[0].positionalArguments[1] as Paint;
    expect(
      paint.colorFilter,
      const ColorFilter.matrix(<double>[
        -1,  0,  0, 0, 255,
         0, -1,  0, 0, 255,
         0,  0, -1, 0, 255,
         0,  0,  0, 1,   0,
      ]),
    );
    expect(commands[1].memberName, #translate);
    expect(commands[1].positionalArguments[0], 0.0);
    expect(commands[1].positionalArguments[1], 100.0);

    expect(commands[2].memberName, #scale);
    expect(commands[2].positionalArguments[0], 1.0);
    expect(commands[2].positionalArguments[1], -1.0);


    expect(commands[3].memberName, #translate);
    expect(commands[3].positionalArguments[0], 0.0);
    expect(commands[3].positionalArguments[1], -100.0);

    expect(
      messages.single,
      'Image TestImage has a display size of 200×100 but a decode size of 300×300, which uses an additional 364kb.\n\n'
      'Consider resizing the asset ahead of time, supplying a cacheWidth parameter of 200, a cacheHeight parameter of 100, or using a ResizeImage.',
    );

    debugInvertOversizedImages = false;
    FlutterError.onError = oldFlutterError;
  });

  testWidgets('Reports Image painting', (WidgetTester tester) async {
    late ImageSizeInfo imageSizeInfo;
    int count = 0;
    debugOnPaintImage = (ImageSizeInfo info) {
      count += 1;
      imageSizeInfo = info;
    };

    final TestCanvas canvas = TestCanvas();
    paintImage(
      canvas: canvas,
      rect: const Rect.fromLTWH(50.0, 75.0, 200.0, 100.0),
      image: image300x300,
      debugImageLabel: 'test.png',
    );

    expect(count, 1);
    expect(imageSizeInfo, isNotNull);
    expect(imageSizeInfo.source, 'test.png');
    expect(imageSizeInfo.imageSize, const Size(300, 300));
    expect(imageSizeInfo.displaySize, const Size(200, 100));

    // Make sure that we don't report an identical image size info if we
    // redraw in the next frame.
    tester.binding.scheduleForcedFrame();
    await tester.pump();

    paintImage(
      canvas: canvas,
      rect: const Rect.fromLTWH(50.0, 75.0, 200.0, 100.0),
      image: image300x300,
      debugImageLabel: 'test.png',
    );

    expect(count, 1);

    debugOnPaintImage = null;
  });

  testWidgets('Reports Image painting - change per frame', (WidgetTester tester) async {
    late ImageSizeInfo imageSizeInfo;
    int count = 0;
    debugOnPaintImage = (ImageSizeInfo info) {
      count += 1;
      imageSizeInfo = info;
    };

    final TestCanvas canvas = TestCanvas();
    paintImage(
      canvas: canvas,
      rect: const Rect.fromLTWH(50.0, 75.0, 200.0, 100.0),
      image: image300x300,
      debugImageLabel: 'test.png',
    );

    expect(count, 1);
    expect(imageSizeInfo, isNotNull);
    expect(imageSizeInfo.source, 'test.png');
    expect(imageSizeInfo.imageSize, const Size(300, 300));
    expect(imageSizeInfo.displaySize, const Size(200, 100));

    // Make sure that we don't report an identical image size info if we
    // redraw in the next frame.
    tester.binding.scheduleForcedFrame();
    await tester.pump();

    paintImage(
      canvas: canvas,
      rect: const Rect.fromLTWH(50.0, 75.0, 200.0, 150.0),
      image: image300x300,
      debugImageLabel: 'test.png',
    );

    expect(count, 2);
    expect(imageSizeInfo, isNotNull);
    expect(imageSizeInfo.source, 'test.png');
    expect(imageSizeInfo.imageSize, const Size(300, 300));
    expect(imageSizeInfo.displaySize, const Size(200, 150));

    debugOnPaintImage = null;
  });

  testWidgets('Reports Image painting - no debug label', (WidgetTester tester) async {
    late ImageSizeInfo imageSizeInfo;
    int count = 0;
    debugOnPaintImage = (ImageSizeInfo info) {
      count += 1;
      imageSizeInfo = info;
    };

    final TestCanvas canvas = TestCanvas();
    paintImage(
      canvas: canvas,
      rect: const Rect.fromLTWH(50.0, 75.0, 200.0, 100.0),
      image: image300x200,
    );

    expect(count, 1);
    expect(imageSizeInfo, isNotNull);
    expect(imageSizeInfo.source, '<Unknown Image(300×200)>');
    expect(imageSizeInfo.imageSize, const Size(300, 200));
    expect(imageSizeInfo.displaySize, const Size(200, 100));

    debugOnPaintImage = null;
  });

  // See also the DecorationImage tests in: decoration_test.dart
}