flutter_flutter/packages/flutter/test/widgets/transform_test.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_test/flutter_test.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/widgets.dart';
import 'package:vector_math/vector_math_64.dart';

void main() {
  testWidgets('Transform origin', (WidgetTester tester) async {
    bool didReceiveTap = false;
    await tester.pumpWidget(
      new Stack(
        children: <Widget>[
          new Positioned(
            top: 100.0,
            left: 100.0,
            child: new Container(
              width: 100.0,
              height: 100.0,
              decoration: new BoxDecoration(
                backgroundColor: new Color(0xFF0000FF),
              ),
            ),
          ),
          new Positioned(
            top: 100.0,
            left: 100.0,
            child: new Container(
              width: 100.0,
              height: 100.0,
              child: new Transform(
                transform: new Matrix4.diagonal3Values(0.5, 0.5, 1.0),
                origin: new Offset(100.0, 50.0),
                child: new GestureDetector(
                  onTap: () {
                    didReceiveTap = true;
                  },
                  child: new Container(
                    decoration: new BoxDecoration(
                      backgroundColor: new Color(0xFF00FFFF),
                    ),
                  ),
                ),
              ),
            ),
          ),
        ],
      ),
    );

    expect(didReceiveTap, isFalse);
    await tester.tapAt(new Point(110.0, 110.0));
    expect(didReceiveTap, isFalse);
    await tester.tapAt(new Point(190.0, 150.0));
    expect(didReceiveTap, isTrue);
  });

  testWidgets('Transform alignment', (WidgetTester tester) async {
    bool didReceiveTap = false;
    await tester.pumpWidget(
      new Stack(
        children: <Widget>[
          new Positioned(
            top: 100.0,
            left: 100.0,
            child: new Container(
              width: 100.0,
              height: 100.0,
              decoration: new BoxDecoration(
                backgroundColor: new Color(0xFF0000FF),
              ),
            ),
          ),
          new Positioned(
            top: 100.0,
            left: 100.0,
            child: new Container(
              width: 100.0,
              height: 100.0,
              child: new Transform(
                transform: new Matrix4.diagonal3Values(0.5, 0.5, 1.0),
                alignment: new FractionalOffset(1.0, 0.5),
                child: new GestureDetector(
                  onTap: () {
                    didReceiveTap = true;
                  },
                  child: new Container(
                    decoration: new BoxDecoration(
                      backgroundColor: new Color(0xFF00FFFF),
                    ),
                  ),
                ),
              ),
            ),
          ),
        ],
      ),
    );

    expect(didReceiveTap, isFalse);
    await tester.tapAt(new Point(110.0, 110.0));
    expect(didReceiveTap, isFalse);
    await tester.tapAt(new Point(190.0, 150.0));
    expect(didReceiveTap, isTrue);
  });

  testWidgets('Transform offset + alignment', (WidgetTester tester) async {
    bool didReceiveTap = false;
    await tester.pumpWidget(new Stack(
      children: <Widget>[
        new Positioned(
          top: 100.0,
          left: 100.0,
          child: new Container(
            width: 100.0,
            height: 100.0,
            decoration: new BoxDecoration(
              backgroundColor: new Color(0xFF0000FF),
            ),
          ),
        ),
        new Positioned(
          top: 100.0,
          left: 100.0,
          child: new Container(
            width: 100.0,
            height: 100.0,
            child: new Transform(
              transform: new Matrix4.diagonal3Values(0.5, 0.5, 1.0),
              origin: new Offset(100.0, 0.0),
              alignment: new FractionalOffset(0.0, 0.5),
              child: new GestureDetector(
                onTap: () {
                  didReceiveTap = true;
                },
                child: new Container(
                  decoration: new BoxDecoration(
                    backgroundColor: new Color(0xFF00FFFF),
                  ),
                ),
              ),
            ),
          ),
        ),
      ],
    ));

    expect(didReceiveTap, isFalse);
    await tester.tapAt(new Point(110.0, 110.0));
    expect(didReceiveTap, isFalse);
    await tester.tapAt(new Point(190.0, 150.0));
    expect(didReceiveTap, isTrue);
  });

  testWidgets('Composited transform offset', (WidgetTester tester) async {
    await tester.pumpWidget(
      new Center(
        child: new SizedBox(
          width: 400.0,
          height: 300.0,
          child: new ClipRect(
            child: new Transform(
              transform: new Matrix4.diagonal3Values(0.5, 0.5, 1.0),
              child: new Opacity(
                opacity: 0.9,
                child: new Container(
                  decoration: new BoxDecoration(
                    backgroundColor: const Color(0xFF00FF00),
                  ),
                ),
              ),
            ),
          ),
        ),
      ),
    );

    List<Layer> layers = tester.layers
      ..retainWhere((Layer layer) => layer is TransformLayer);
    expect(layers.length, 2);
    // The first transform is from the render view.
    TransformLayer layer = layers[1];
    Matrix4 transform = layer.transform;
    expect(transform.getTranslation(), equals(new Vector3(100.0, 75.0, 0.0)));
  });
}