flutter_flutter/testing/dart/encoding_test.dart
2018-04-16 15:10:40 -07:00

89 lines
2.7 KiB
Dart

// Copyright 2018 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 'dart:async';
import 'dart:ui';
import 'dart:typed_data';
import 'dart:io';
import 'package:path/path.dart' as path;
import 'package:test/test.dart';
const int _kWidth = 10;
const int _kRadius = 2;
const Color _kBlack = const Color.fromRGBO(0, 0, 0, 1.0);
const Color _kGreen = const Color.fromRGBO(0, 255, 0, 1.0);
void main() {
group('Image.toByteData', () {
test('Encode with default arguments', () async {
Image testImage = createSquareTestImage();
ByteData data = await testImage.toByteData();
expect(new Uint8List.view(data.buffer), getExpectedBytes());
});
test('Handles grayscale images', () async {
File grayscaleImage = new File(path.join('flutter', 'testing', 'resources', '4x4.png'));
Uint8List png = await grayscaleImage.readAsBytes();
Completer<Image> completer = new Completer<Image>();
decodeImageFromList(png, (Image image) => completer.complete(image));
Image image = await completer.future;
ByteData data = await image.toByteData();
Uint8List bytes = data.buffer.asUint8List();
expect(bytes, hasLength(16));
expect(bytes, <int>[
255, 255, 255, 255,
127, 127, 127, 255,
127, 127, 127, 255,
0, 0, 0, 255,
]);
});
});
}
Image createSquareTestImage() {
double width = _kWidth.toDouble();
double radius = _kRadius.toDouble();
double innerWidth = (_kWidth - 2 * _kRadius).toDouble();
PictureRecorder recorder = new PictureRecorder();
Canvas canvas =
new Canvas(recorder, new Rect.fromLTWH(0.0, 0.0, width, width));
Paint black = new Paint()
..strokeWidth = 1.0
..color = _kBlack;
Paint green = new Paint()
..strokeWidth = 1.0
..color = _kGreen;
canvas.drawRect(new Rect.fromLTWH(0.0, 0.0, width, width), black);
canvas.drawRect(
new Rect.fromLTWH(radius, radius, innerWidth, innerWidth), green);
return recorder.endRecording().toImage(_kWidth, _kWidth);
}
List<int> getExpectedBytes() {
int bytesPerChannel = 4;
List<int> result = new List<int>(_kWidth * _kWidth * bytesPerChannel);
fillWithColor(Color color, int min, int max) {
for (int i = min; i < max; i++) {
for (int j = min; j < max; j++) {
int offset = i * bytesPerChannel + j * _kWidth * bytesPerChannel;
result[offset] = color.red;
result[offset + 1] = color.green;
result[offset + 2] = color.blue;
result[offset + 3] = color.alpha;
}
}
}
fillWithColor(_kBlack, 0, _kWidth);
fillWithColor(_kGreen, _kRadius, _kWidth - _kRadius);
return result;
}