flutter/packages/flutter/test/gestures/velocity_tracker_test.dart

51 lines
1.8 KiB
Dart

// Copyright 2015 The Chromium 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 'package:flutter/gestures.dart';
import 'package:test/test.dart';
import 'velocity_tracker_data.dart';
bool _withinTolerance(double actual, double expected) {
const double kTolerance = 0.001; // Within .1% of expected value
double diff = (actual - expected)/expected;
return diff.abs() < kTolerance;
}
bool _checkVelocity(Offset actual, Offset expected) {
return (actual != null)
&& _withinTolerance(actual.dx, expected.dx)
&& _withinTolerance(actual.dy, expected.dy);
}
void main() {
List<Offset> expected = const <Offset>[
const Offset(219.5762939453125, 1304.6705322265625),
const Offset(355.6900939941406, 967.1700439453125),
const Offset(12.651158332824707, -36.9227180480957),
const Offset(714.1383056640625, -2561.540283203125),
const Offset(-19.658065795898438, -2910.080322265625),
const Offset(646.8700561523438, 2976.982421875),
const Offset(396.6878967285156, 2106.204833984375),
const Offset(298.3150634765625, -3660.821044921875),
const Offset(-1.7460877895355225, -3288.16162109375),
const Offset(384.6415710449219, -2645.6484375),
const Offset(176.3752899169922, 2711.24609375),
const Offset(396.9254455566406, 4280.640625),
const Offset(-71.51288604736328, 3716.74560546875),
];
test('Velocity tracker gives expected results', () {
VelocityTracker tracker = new VelocityTracker();
int i = 0;
for (PointerEvent event in velocityEventData) {
if (event is PointerDownEvent || event is PointerMoveEvent)
tracker.addPosition(event.timeStamp, event.position);
if (event is PointerUpEvent) {
_checkVelocity(tracker.getVelocity(), expected[i]);
i += 1;
}
}
});
}