testing/dart/path_test.dart - mirrors/engine - Git at Google

 // Copyright 2013 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:typed_data' show Float64List;
 import 'dart:ui';

 import 'package:litetest/litetest.dart';

 void main() {
   test('path getBounds', () {
     const Rect r = Rect.fromLTRB(1.0, 3.0, 5.0, 7.0);
     final Path p = Path()..addRect(r);
     expect(p.getBounds(), equals(r));
     p.lineTo(20.0, 15.0);
     expect(p.getBounds(), equals(const Rect.fromLTRB(1.0, 3.0, 20.0, 15.0)));
   });

   test('path combine rect', () {
     final Rect c1 = Rect.fromCircle(center: const Offset(10.0, 10.0), radius: 10.0);
     final Rect c2 = Rect.fromCircle(center: const Offset(5.0, 5.0), radius: 10.0);
     final Rect c1UnionC2 = c1.expandToInclude(c2);
     final Rect c1IntersectC2 = c1.intersect(c2);
     final Path pathCircle1 = Path()..addRect(c1);
     final Path pathCircle2 = Path()..addRect(c2);

     final Path difference = Path.combine(PathOperation.difference, pathCircle1, pathCircle2);
     expect(difference.getBounds(), equals(c1));

     final Path reverseDifference = Path.combine(PathOperation.reverseDifference, pathCircle1, pathCircle2);
     expect(reverseDifference.getBounds(), equals(c2));

     final Path union = Path.combine(PathOperation.union, pathCircle1, pathCircle2);
     expect(union.getBounds(), equals(c1UnionC2));

     final Path intersect = Path.combine(PathOperation.intersect, pathCircle1, pathCircle2);
     expect(intersect.getBounds(), equals(c1IntersectC2));

     // the bounds on this will be the same as union - but would draw a missing inside piece.
     final Path xor = Path.combine(PathOperation.xor, pathCircle1, pathCircle2);
     expect(xor.getBounds(), equals(c1UnionC2));
   });

   test('path combine oval', () {
     final Rect c1 = Rect.fromCircle(center: const Offset(10.0, 10.0), radius: 10.0);
     final Rect c2 = Rect.fromCircle(center: const Offset(5.0, 5.0), radius: 10.0);
     final Rect c1UnionC2 = c1.expandToInclude(c2);
     final Rect c1IntersectC2 = c1.intersect(c2);
     final Path pathCircle1 = Path()..addOval(c1);
     final Path pathCircle2 = Path()..addOval(c2);

     final Path difference = Path.combine(PathOperation.difference, pathCircle1, pathCircle2);

     expect(difference.getBounds().top, closeTo(0.88, 0.01));

     final Path reverseDifference = Path.combine(PathOperation.reverseDifference, pathCircle1, pathCircle2);
     expect(reverseDifference.getBounds().right, closeTo(14.11, 0.01));

     final Path union = Path.combine(PathOperation.union, pathCircle1, pathCircle2);
     expect(union.getBounds(), equals(c1UnionC2));

     final Path intersect = Path.combine(PathOperation.intersect, pathCircle1, pathCircle2);
     expect(intersect.getBounds(), equals(c1IntersectC2));

     // the bounds on this will be the same as union - but would draw a missing inside piece.
     final Path xor = Path.combine(PathOperation.xor, pathCircle1, pathCircle2);
     expect(xor.getBounds(), equals(c1UnionC2));
   });

   test('path clone', () {
     final Path p1 = Path()..lineTo(20.0, 20.0);
     final Path p2 = Path.from(p1);

     expect(p1.getBounds(), equals(p2.getBounds()));

     p1.lineTo(10.0, 30.0);
     expect(p1.getBounds().bottom, equals(p2.getBounds().bottom + 10));
   });

   test('shift tests', () {
     const Rect bounds = Rect.fromLTRB(0.0, 0.0, 10.0, 10.0);
     final Path p = Path()..addRect(bounds);
     expect(p.getBounds(), equals(bounds));
     final Path shifted = p.shift(const Offset(10, 10));
     expect(shifted.getBounds(), equals(const Rect.fromLTRB(10, 10, 20, 20)));
   });

   test('transformation tests', () {
     const Rect bounds = Rect.fromLTRB(0.0, 0.0, 10.0, 10.0);
     final Path p = Path()..addRect(bounds);
     final Float64List scaleMatrix = Float64List.fromList(<double>[
       2.5, 0.0, 0.0, 0.0, // first col
       0.0, 0.5, 0.0, 0.0, // second col
       0.0, 0.0, 1.0, 0.0, // third col
       0.0, 0.0, 0.0, 1.0, // fourth col
     ]);

     expect(p.getBounds(), equals(bounds));
     final Path pTransformed = p.transform(scaleMatrix);

     expect(pTransformed.getBounds(),
         equals(const Rect.fromLTRB(0.0, 0.0, 10 * 2.5, 10 * 0.5)));

     final Path p2 = Path()..lineTo(10.0, 10.0);

     p.addPath(p2, const Offset(10.0, 10.0));
     expect(p.getBounds(), equals(const Rect.fromLTRB(0.0, 0.0, 20.0, 20.0)));

     p.addPath(p2, const Offset(20.0, 20.0), matrix4: scaleMatrix);
     expect(p.getBounds(),
         equals(const Rect.fromLTRB(0.0, 0.0, 20 + (10 * 2.5), 20 + (10 * .5))));

     p.extendWithPath(p2, Offset.zero);
     expect(p.getBounds(), equals(const Rect.fromLTRB(0.0, 0.0, 45.0, 25.0)));

     p.extendWithPath(p2, const Offset(45.0, 25.0), matrix4: scaleMatrix);
     expect(p.getBounds(), equals(const Rect.fromLTRB(0.0, 0.0, 70.0, 30.0)));
   });

   test('path metrics tests', () {
     final Path simpleHorizontalLine = Path()..lineTo(10.0, 0.0);

     // basic tests on horizontal line
     final PathMetrics simpleHorizontalMetrics = simpleHorizontalLine.computeMetrics();
     expect(() => simpleHorizontalMetrics.iterator.current, throwsRangeError);
     expect(simpleHorizontalMetrics.iterator.moveNext(), isTrue);
     expect(simpleHorizontalMetrics.iterator.current, isNotNull);
     expect(simpleHorizontalMetrics.iterator.current.length, equals(10.0));
     expect(simpleHorizontalMetrics.iterator.current.isClosed, isFalse);
     final Path simpleExtract = simpleHorizontalMetrics.iterator.current.extractPath(1.0, 9.0);
     expect(simpleExtract.getBounds(), equals(const Rect.fromLTRB(1.0, 0.0, 9.0, 0.0)));
     final Tangent posTan = simpleHorizontalMetrics.iterator.current.getTangentForOffset(1.0)!;
     expect(posTan.position, equals(const Offset(1.0, 0.0)));
     expect(posTan.angle, equals(0.0));

     expect(simpleHorizontalMetrics.iterator.moveNext(), isFalse);
     expect(() => simpleHorizontalMetrics.iterator.current, throwsRangeError);

     // test with forceClosed
     final PathMetrics simpleMetricsClosed = simpleHorizontalLine.computeMetrics(forceClosed: true);
     expect(() => simpleHorizontalMetrics.iterator.current, throwsRangeError);
     expect(simpleMetricsClosed.iterator.moveNext(), isTrue);
     expect(simpleMetricsClosed.iterator.current, isNotNull);
     expect(simpleMetricsClosed.iterator.current.length, equals(20.0)); // because we forced close
     expect(simpleMetricsClosed.iterator.current.isClosed, isTrue);
     final Path simpleExtract2 = simpleMetricsClosed.iterator.current.extractPath(1.0, 9.0);
     expect(simpleExtract2.getBounds(), equals(const Rect.fromLTRB(1.0, 0.0, 9.0, 0.0)));
     expect(simpleMetricsClosed.iterator.moveNext(), isFalse);

     // test getTangentForOffset with vertical line
     final Path simpleVerticalLine = Path()..lineTo(0.0, 10.0);
     final PathMetrics simpleMetricsVertical = simpleVerticalLine.computeMetrics()..iterator.moveNext();
     final Tangent posTanVertical = simpleMetricsVertical.iterator.current.getTangentForOffset(5.0)!;
     expect(posTanVertical.position, equals(const Offset(0.0, 5.0)));
     expect(posTanVertical.angle, closeTo(-1.5708, .0001)); // 90 degrees

     // test getTangentForOffset with diagonal line
     final Path simpleDiagonalLine = Path()..lineTo(10.0, 10.0);
     final PathMetrics simpleMetricsDiagonal = simpleDiagonalLine.computeMetrics()..iterator.moveNext();
     final double midPoint = simpleMetricsDiagonal.iterator.current.length / 2;
     final Tangent posTanDiagonal = simpleMetricsDiagonal.iterator.current.getTangentForOffset(midPoint)!;
     expect(posTanDiagonal.position, equals(const Offset(5.0, 5.0)));
     expect(posTanDiagonal.angle, closeTo(-0.7853981633974483, .00001)); // ~45 degrees

     // test a multi-contour path
     final Path multiContour = Path()
       ..lineTo(0.0, 10.0)
       ..moveTo(10.0, 10.0)
       ..lineTo(10.0, 15.0);

     final PathMetrics multiContourMetric = multiContour.computeMetrics();
     expect(() => multiContourMetric.iterator.current, throwsRangeError);
     expect(multiContourMetric.iterator.moveNext(), isTrue);
     expect(multiContourMetric.iterator.current, isNotNull);
     expect(multiContourMetric.iterator.current.length, equals(10.0));
     expect(multiContourMetric.iterator.moveNext(), isTrue);
     expect(multiContourMetric.iterator.current, isNotNull);
     expect(multiContourMetric.iterator.current.length, equals(5.0));
     expect(multiContourMetric.iterator.moveNext(), isFalse);
     expect(() => multiContourMetric.iterator.current, throwsRangeError);
   });

   test('PathMetrics can remember lengths and isClosed', () {
     final Path path = Path()..lineTo(0, 10)
                             ..close()
                             ..moveTo(0, 15)
                             ..lineTo(10, 15);
     final List<PathMetric> metrics = path.computeMetrics().toList();
     expect(metrics.length, 2);
     expect(metrics[0].length, 20);
     expect(metrics[0].isClosed, true);
     expect(metrics[0].getTangentForOffset(4.0)!.vector, const Offset(0.0, 1.0));
     expect(metrics[0].extractPath(4.0, 10.0).computeMetrics().first.length, 6.0);
     expect(metrics[1].length, 10);
     expect(metrics[1].isClosed, false);
     expect(metrics[1].getTangentForOffset(4.0)!.vector, const Offset(1.0, 0.0));
     expect(metrics[1].extractPath(4.0, 6.0).computeMetrics().first.length, 2.0);
   });

   test('PathMetrics on a mutated path', () {
     final Path path = Path()..lineTo(0, 10);
     final PathMetrics metrics = path.computeMetrics();
     final PathMetric firstMetric = metrics.first;
     // We've consumed the iterator.
     expect(metrics, isEmpty);
     expect(firstMetric.length, 10);
     expect(firstMetric.isClosed, false);
     expect(firstMetric.getTangentForOffset(4.0)!.vector, const Offset(0.0, 1.0));
     expect(firstMetric.extractPath(4.0, 10.0).computeMetrics().first.length, 6.0);

     path..lineTo(10, 10)..lineTo(10, 0)..close();
     // mutating the path shouldn't have added anything to the iterator.
     expect(metrics, isEmpty);
     expect(firstMetric.length, 10);
     expect(firstMetric.isClosed, false);
     expect(firstMetric.getTangentForOffset(4.0)!.vector, const Offset(0.0, 1.0));
     expect(firstMetric.extractPath(4.0, 10.0).computeMetrics().first.length, 6.0);

     // getting a new iterator should update us.
     final PathMetrics newMetrics = path.computeMetrics();
     final PathMetric newFirstMetric = newMetrics.first;
     expect(newMetrics, isEmpty);
     expect(newFirstMetric.length, 40);
     expect(newFirstMetric.isClosed, true);
     expect(newFirstMetric.getTangentForOffset(4.0)!.vector, const Offset(0.0, 1.0));
     expect(newFirstMetric.extractPath(4.0, 10.0).computeMetrics().first.length, 6.0);
   });

   test('PathMetrics on a mutated path', () {
     final Path path = Path()
       ..lineTo(0, 30)
       ..lineTo(40, 30)
       ..moveTo(100, 0)
       ..lineTo(100, 30)
       ..lineTo(140, 30)
       ..close();
     final PathMetrics metrics = path.computeMetrics();
     expect(metrics.toString(),
       '(PathMetric(length: 70.0, isClosed: false, contourIndex: 0), '
        'PathMetric(length: 120.0, isClosed: true, contourIndex: 1))',
     );
   });
 }
	// Copyright 2013 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:typed_data' show Float64List;
	import 'dart:ui';

	import 'package:litetest/litetest.dart';

	void main() {
	test('path getBounds', () {
	const Rect r = Rect.fromLTRB(1.0, 3.0, 5.0, 7.0);
	final Path p = Path()..addRect(r);
	expect(p.getBounds(), equals(r));
	p.lineTo(20.0, 15.0);
	expect(p.getBounds(), equals(const Rect.fromLTRB(1.0, 3.0, 20.0, 15.0)));
	});

	test('path combine rect', () {
	final Rect c1 = Rect.fromCircle(center: const Offset(10.0, 10.0), radius: 10.0);
	final Rect c2 = Rect.fromCircle(center: const Offset(5.0, 5.0), radius: 10.0);
	final Rect c1UnionC2 = c1.expandToInclude(c2);
	final Rect c1IntersectC2 = c1.intersect(c2);
	final Path pathCircle1 = Path()..addRect(c1);
	final Path pathCircle2 = Path()..addRect(c2);

	final Path difference = Path.combine(PathOperation.difference, pathCircle1, pathCircle2);
	expect(difference.getBounds(), equals(c1));

	final Path reverseDifference = Path.combine(PathOperation.reverseDifference, pathCircle1, pathCircle2);
	expect(reverseDifference.getBounds(), equals(c2));

	final Path union = Path.combine(PathOperation.union, pathCircle1, pathCircle2);
	expect(union.getBounds(), equals(c1UnionC2));

	final Path intersect = Path.combine(PathOperation.intersect, pathCircle1, pathCircle2);
	expect(intersect.getBounds(), equals(c1IntersectC2));

	// the bounds on this will be the same as union - but would draw a missing inside piece.
	final Path xor = Path.combine(PathOperation.xor, pathCircle1, pathCircle2);
	expect(xor.getBounds(), equals(c1UnionC2));
	});

	test('path combine oval', () {
	final Rect c1 = Rect.fromCircle(center: const Offset(10.0, 10.0), radius: 10.0);
	final Rect c2 = Rect.fromCircle(center: const Offset(5.0, 5.0), radius: 10.0);
	final Rect c1UnionC2 = c1.expandToInclude(c2);
	final Rect c1IntersectC2 = c1.intersect(c2);
	final Path pathCircle1 = Path()..addOval(c1);
	final Path pathCircle2 = Path()..addOval(c2);

	final Path difference = Path.combine(PathOperation.difference, pathCircle1, pathCircle2);

	expect(difference.getBounds().top, closeTo(0.88, 0.01));

	final Path reverseDifference = Path.combine(PathOperation.reverseDifference, pathCircle1, pathCircle2);
	expect(reverseDifference.getBounds().right, closeTo(14.11, 0.01));

	final Path union = Path.combine(PathOperation.union, pathCircle1, pathCircle2);
	expect(union.getBounds(), equals(c1UnionC2));

	final Path intersect = Path.combine(PathOperation.intersect, pathCircle1, pathCircle2);
	expect(intersect.getBounds(), equals(c1IntersectC2));

	// the bounds on this will be the same as union - but would draw a missing inside piece.
	final Path xor = Path.combine(PathOperation.xor, pathCircle1, pathCircle2);
	expect(xor.getBounds(), equals(c1UnionC2));
	});

	test('path clone', () {
	final Path p1 = Path()..lineTo(20.0, 20.0);
	final Path p2 = Path.from(p1);

	expect(p1.getBounds(), equals(p2.getBounds()));

	p1.lineTo(10.0, 30.0);
	expect(p1.getBounds().bottom, equals(p2.getBounds().bottom + 10));
	});

	test('shift tests', () {
	const Rect bounds = Rect.fromLTRB(0.0, 0.0, 10.0, 10.0);
	final Path p = Path()..addRect(bounds);
	expect(p.getBounds(), equals(bounds));
	final Path shifted = p.shift(const Offset(10, 10));
	expect(shifted.getBounds(), equals(const Rect.fromLTRB(10, 10, 20, 20)));
	});

	test('transformation tests', () {
	const Rect bounds = Rect.fromLTRB(0.0, 0.0, 10.0, 10.0);
	final Path p = Path()..addRect(bounds);
	final Float64List scaleMatrix = Float64List.fromList(<double>[
	2.5, 0.0, 0.0, 0.0, // first col
	0.0, 0.5, 0.0, 0.0, // second col
	0.0, 0.0, 1.0, 0.0, // third col
	0.0, 0.0, 0.0, 1.0, // fourth col
	]);

	expect(p.getBounds(), equals(bounds));
	final Path pTransformed = p.transform(scaleMatrix);

	expect(pTransformed.getBounds(),
	equals(const Rect.fromLTRB(0.0, 0.0, 10 * 2.5, 10 * 0.5)));

	final Path p2 = Path()..lineTo(10.0, 10.0);

	p.addPath(p2, const Offset(10.0, 10.0));
	expect(p.getBounds(), equals(const Rect.fromLTRB(0.0, 0.0, 20.0, 20.0)));

	p.addPath(p2, const Offset(20.0, 20.0), matrix4: scaleMatrix);
	expect(p.getBounds(),
	equals(const Rect.fromLTRB(0.0, 0.0, 20 + (10 * 2.5), 20 + (10 * .5))));

	p.extendWithPath(p2, Offset.zero);
	expect(p.getBounds(), equals(const Rect.fromLTRB(0.0, 0.0, 45.0, 25.0)));

	p.extendWithPath(p2, const Offset(45.0, 25.0), matrix4: scaleMatrix);
	expect(p.getBounds(), equals(const Rect.fromLTRB(0.0, 0.0, 70.0, 30.0)));
	});

	test('path metrics tests', () {
	final Path simpleHorizontalLine = Path()..lineTo(10.0, 0.0);

	// basic tests on horizontal line
	final PathMetrics simpleHorizontalMetrics = simpleHorizontalLine.computeMetrics();
	expect(() => simpleHorizontalMetrics.iterator.current, throwsRangeError);
	expect(simpleHorizontalMetrics.iterator.moveNext(), isTrue);
	expect(simpleHorizontalMetrics.iterator.current, isNotNull);
	expect(simpleHorizontalMetrics.iterator.current.length, equals(10.0));
	expect(simpleHorizontalMetrics.iterator.current.isClosed, isFalse);
	final Path simpleExtract = simpleHorizontalMetrics.iterator.current.extractPath(1.0, 9.0);
	expect(simpleExtract.getBounds(), equals(const Rect.fromLTRB(1.0, 0.0, 9.0, 0.0)));
	final Tangent posTan = simpleHorizontalMetrics.iterator.current.getTangentForOffset(1.0)!;
	expect(posTan.position, equals(const Offset(1.0, 0.0)));
	expect(posTan.angle, equals(0.0));

	expect(simpleHorizontalMetrics.iterator.moveNext(), isFalse);
	expect(() => simpleHorizontalMetrics.iterator.current, throwsRangeError);

	// test with forceClosed
	final PathMetrics simpleMetricsClosed = simpleHorizontalLine.computeMetrics(forceClosed: true);
	expect(() => simpleHorizontalMetrics.iterator.current, throwsRangeError);
	expect(simpleMetricsClosed.iterator.moveNext(), isTrue);
	expect(simpleMetricsClosed.iterator.current, isNotNull);
	expect(simpleMetricsClosed.iterator.current.length, equals(20.0)); // because we forced close
	expect(simpleMetricsClosed.iterator.current.isClosed, isTrue);
	final Path simpleExtract2 = simpleMetricsClosed.iterator.current.extractPath(1.0, 9.0);
	expect(simpleExtract2.getBounds(), equals(const Rect.fromLTRB(1.0, 0.0, 9.0, 0.0)));
	expect(simpleMetricsClosed.iterator.moveNext(), isFalse);

	// test getTangentForOffset with vertical line
	final Path simpleVerticalLine = Path()..lineTo(0.0, 10.0);
	final PathMetrics simpleMetricsVertical = simpleVerticalLine.computeMetrics()..iterator.moveNext();
	final Tangent posTanVertical = simpleMetricsVertical.iterator.current.getTangentForOffset(5.0)!;
	expect(posTanVertical.position, equals(const Offset(0.0, 5.0)));
	expect(posTanVertical.angle, closeTo(-1.5708, .0001)); // 90 degrees

	// test getTangentForOffset with diagonal line
	final Path simpleDiagonalLine = Path()..lineTo(10.0, 10.0);
	final PathMetrics simpleMetricsDiagonal = simpleDiagonalLine.computeMetrics()..iterator.moveNext();
	final double midPoint = simpleMetricsDiagonal.iterator.current.length / 2;
	final Tangent posTanDiagonal = simpleMetricsDiagonal.iterator.current.getTangentForOffset(midPoint)!;
	expect(posTanDiagonal.position, equals(const Offset(5.0, 5.0)));
	expect(posTanDiagonal.angle, closeTo(-0.7853981633974483, .00001)); // ~45 degrees

	// test a multi-contour path
	final Path multiContour = Path()
	..lineTo(0.0, 10.0)
	..moveTo(10.0, 10.0)
	..lineTo(10.0, 15.0);

	final PathMetrics multiContourMetric = multiContour.computeMetrics();
	expect(() => multiContourMetric.iterator.current, throwsRangeError);
	expect(multiContourMetric.iterator.moveNext(), isTrue);
	expect(multiContourMetric.iterator.current, isNotNull);
	expect(multiContourMetric.iterator.current.length, equals(10.0));
	expect(multiContourMetric.iterator.moveNext(), isTrue);
	expect(multiContourMetric.iterator.current, isNotNull);
	expect(multiContourMetric.iterator.current.length, equals(5.0));
	expect(multiContourMetric.iterator.moveNext(), isFalse);
	expect(() => multiContourMetric.iterator.current, throwsRangeError);
	});

	test('PathMetrics can remember lengths and isClosed', () {
	final Path path = Path()..lineTo(0, 10)
	..close()
	..moveTo(0, 15)
	..lineTo(10, 15);
	final List<PathMetric> metrics = path.computeMetrics().toList();
	expect(metrics.length, 2);
	expect(metrics[0].length, 20);
	expect(metrics[0].isClosed, true);
	expect(metrics[0].getTangentForOffset(4.0)!.vector, const Offset(0.0, 1.0));
	expect(metrics[0].extractPath(4.0, 10.0).computeMetrics().first.length, 6.0);
	expect(metrics[1].length, 10);
	expect(metrics[1].isClosed, false);
	expect(metrics[1].getTangentForOffset(4.0)!.vector, const Offset(1.0, 0.0));
	expect(metrics[1].extractPath(4.0, 6.0).computeMetrics().first.length, 2.0);
	});

	test('PathMetrics on a mutated path', () {
	final Path path = Path()..lineTo(0, 10);
	final PathMetrics metrics = path.computeMetrics();
	final PathMetric firstMetric = metrics.first;
	// We've consumed the iterator.
	expect(metrics, isEmpty);
	expect(firstMetric.length, 10);
	expect(firstMetric.isClosed, false);
	expect(firstMetric.getTangentForOffset(4.0)!.vector, const Offset(0.0, 1.0));
	expect(firstMetric.extractPath(4.0, 10.0).computeMetrics().first.length, 6.0);

	path..lineTo(10, 10)..lineTo(10, 0)..close();
	// mutating the path shouldn't have added anything to the iterator.
	expect(metrics, isEmpty);
	expect(firstMetric.length, 10);
	expect(firstMetric.isClosed, false);
	expect(firstMetric.getTangentForOffset(4.0)!.vector, const Offset(0.0, 1.0));
	expect(firstMetric.extractPath(4.0, 10.0).computeMetrics().first.length, 6.0);

	// getting a new iterator should update us.
	final PathMetrics newMetrics = path.computeMetrics();
	final PathMetric newFirstMetric = newMetrics.first;
	expect(newMetrics, isEmpty);
	expect(newFirstMetric.length, 40);
	expect(newFirstMetric.isClosed, true);
	expect(newFirstMetric.getTangentForOffset(4.0)!.vector, const Offset(0.0, 1.0));
	expect(newFirstMetric.extractPath(4.0, 10.0).computeMetrics().first.length, 6.0);
	});

	test('PathMetrics on a mutated path', () {
	final Path path = Path()
	..lineTo(0, 30)
	..lineTo(40, 30)
	..moveTo(100, 0)
	..lineTo(100, 30)
	..lineTo(140, 30)
	..close();
	final PathMetrics metrics = path.computeMetrics();
	expect(metrics.toString(),
	'(PathMetric(length: 70.0, isClosed: false, contourIndex: 0), '
	'PathMetric(length: 120.0, isClosed: true, contourIndex: 1))',
	);
	});
	}