packages/flutter/test/rendering/paragraph_test.dart

// Copyright 2016 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:io';
import 'dart:ui' as ui show TextBox;

import 'package:flutter/rendering.dart';
import 'package:flutter/services.dart';
import 'package:flutter_test/flutter_test.dart';

import 'rendering_tester.dart';

const String _kText = 'I polished up that handle so carefullee\nThat now I am the Ruler of the Queen\'s Navee!';

void main() {
  test('getOffsetForCaret control test', () {
    final RenderParagraph paragraph = new RenderParagraph(
      const TextSpan(text: _kText),
      textDirection: TextDirection.ltr,
    );
    layout(paragraph);

    final Rect caret = new Rect.fromLTWH(0.0, 0.0, 2.0, 20.0);

    final Offset offset5 = paragraph.getOffsetForCaret(const TextPosition(offset: 5), caret);
    expect(offset5.dx, greaterThan(0.0));

    final Offset offset25 = paragraph.getOffsetForCaret(const TextPosition(offset: 25), caret);
    expect(offset25.dx, greaterThan(offset5.dx));

    final Offset offset50 = paragraph.getOffsetForCaret(const TextPosition(offset: 50), caret);
    expect(offset50.dy, greaterThan(offset5.dy));
  });

  test('getPositionForOffset control test', () {
    final RenderParagraph paragraph = new RenderParagraph(
      const TextSpan(text: _kText),
      textDirection: TextDirection.ltr,
    );
    layout(paragraph);

    final TextPosition position20 = paragraph.getPositionForOffset(const Offset(20.0, 5.0));
    expect(position20.offset, greaterThan(0.0));

    final TextPosition position40 = paragraph.getPositionForOffset(const Offset(40.0, 5.0));
    expect(position40.offset, greaterThan(position20.offset));

    final TextPosition positionBelow = paragraph.getPositionForOffset(const Offset(5.0, 20.0));
    expect(positionBelow.offset, greaterThan(position40.offset));
  });

  test('getBoxesForSelection control test', () {
    final RenderParagraph paragraph = new RenderParagraph(
      const TextSpan(text: _kText, style: const TextStyle(fontSize: 10.0)),
      textDirection: TextDirection.ltr,
    );
    layout(paragraph);

    List<ui.TextBox> boxes = paragraph.getBoxesForSelection(
        const TextSelection(baseOffset: 5, extentOffset: 25)
    );

    expect(boxes.length, equals(1));

    boxes = paragraph.getBoxesForSelection(
        const TextSelection(baseOffset: 25, extentOffset: 50)
    );

    expect(boxes.any((ui.TextBox box) => box.left == 250 && box.top == 0), isTrue);
    expect(boxes.any((ui.TextBox box) => box.right == 100 && box.top == 10), isTrue);
  },
  // Ahem-based tests don't yet quite work on Windows or some MacOS environments
  skip: Platform.isWindows || Platform.isMacOS);

  test('getWordBoundary control test', () {
    final RenderParagraph paragraph = new RenderParagraph(
      const TextSpan(text: _kText),
      textDirection: TextDirection.ltr,
    );
    layout(paragraph);

    final TextRange range5 = paragraph.getWordBoundary(const TextPosition(offset: 5));
    expect(range5.textInside(_kText), equals('polished'));

    final TextRange range50 = paragraph.getWordBoundary(const TextPosition(offset: 50));
    expect(range50.textInside(_kText), equals(' '));

    final TextRange range85 = paragraph.getWordBoundary(const TextPosition(offset: 75));
    expect(range85.textInside(_kText), equals('Queen\'s'));
  });

  test('overflow test', () {
    final RenderParagraph paragraph = new RenderParagraph(
      const TextSpan(
        text: 'This\n' // 4 characters * 10px font size = 40px width on the first line
              'is a wrapping test. It should wrap at manual newlines, and if softWrap is true, also at spaces.',
        style: const TextStyle(fontFamily: 'Ahem', fontSize: 10.0),
      ),
      textDirection: TextDirection.ltr,
      maxLines: 1,
      softWrap: true,
    );

    void relayoutWith({ int maxLines, bool softWrap, TextOverflow overflow }) {
      paragraph
        ..maxLines = maxLines
        ..softWrap = softWrap
        ..overflow = overflow;
      pumpFrame();
    }

    // Lay out in a narrow box to force wrapping.
    layout(paragraph, constraints: const BoxConstraints(maxWidth: 50.0)); // enough to fit "This" but not "This is"
    final double lineHeight = paragraph.size.height;

    relayoutWith(maxLines: 3, softWrap: true, overflow: TextOverflow.clip);
    expect(paragraph.size.height, equals(3 * lineHeight));

    relayoutWith(maxLines: null, softWrap: true, overflow: TextOverflow.clip);
    expect(paragraph.size.height, greaterThan(5 * lineHeight));

    // Try again with ellipsis overflow. We can't test that the ellipsis are
    // drawn, but we can test the sizing.
    relayoutWith(maxLines: 1, softWrap: true, overflow: TextOverflow.ellipsis);
    expect(paragraph.size.height, equals(lineHeight));

    relayoutWith(maxLines: 3, softWrap: true, overflow: TextOverflow.ellipsis);
    expect(paragraph.size.height, equals(3 * lineHeight));

    // This is the one weird case. If maxLines is null, we would expect to allow
    // infinite wrapping. However, if we did, we'd never know when to append an
    // ellipsis, so this really means "append ellipsis as soon as we exceed the
    // width".
    relayoutWith(maxLines: null, softWrap: true, overflow: TextOverflow.ellipsis);
    expect(paragraph.size.height, equals(2 * lineHeight));

    // Now with no soft wrapping.
    relayoutWith(maxLines: 1, softWrap: false, overflow: TextOverflow.clip);
    expect(paragraph.size.height, equals(lineHeight));

    relayoutWith(maxLines: 3, softWrap: false, overflow: TextOverflow.clip);
    expect(paragraph.size.height, equals(2 * lineHeight));

    relayoutWith(maxLines: null, softWrap: false, overflow: TextOverflow.clip);
    expect(paragraph.size.height, equals(2 * lineHeight));

    relayoutWith(maxLines: 1, softWrap: false, overflow: TextOverflow.ellipsis);
    expect(paragraph.size.height, equals(lineHeight));

    relayoutWith(maxLines: 3, softWrap: false, overflow: TextOverflow.ellipsis);
    expect(paragraph.size.height, equals(3 * lineHeight));

    relayoutWith(maxLines: null, softWrap: false, overflow: TextOverflow.ellipsis);
    expect(paragraph.size.height, equals(2 * lineHeight));

    // Test presence of the fade effect.
    relayoutWith(maxLines: 3, softWrap: true, overflow: TextOverflow.fade);
    expect(paragraph.debugHasOverflowShader, isTrue);

    // Change back to ellipsis and check that the fade shader is cleared.
    relayoutWith(maxLines: 3, softWrap: true, overflow: TextOverflow.ellipsis);
    expect(paragraph.debugHasOverflowShader, isFalse);

    relayoutWith(maxLines: 100, softWrap: true, overflow: TextOverflow.fade);
    expect(paragraph.debugHasOverflowShader, isFalse);
  });

  test('maxLines', () {
    final RenderParagraph paragraph = new RenderParagraph(
      const TextSpan(
        text: 'How do you write like you\'re running out of time? Write day and night like you\'re running out of time?',
            // 0123456789 0123456789 012 345 0123456 012345 01234 012345678 012345678 0123 012 345 0123456 012345 01234
            // 0          1          2       3       4      5     6         7         8    9       10      11     12
        style: const TextStyle(fontFamily: 'Ahem', fontSize: 10.0),
      ),
      textDirection: TextDirection.ltr,
    );
    layout(paragraph, constraints: const BoxConstraints(maxWidth: 100.0));
    void layoutAt(int maxLines) {
      paragraph.maxLines = maxLines;
      pumpFrame();
    }

    layoutAt(null);
    expect(paragraph.size.height, 130.0);

    layoutAt(1);
    expect(paragraph.size.height, 10.0);

    layoutAt(2);
    expect(paragraph.size.height, 20.0);

    layoutAt(3);
    expect(paragraph.size.height, 30.0);
  }, skip: Platform.isWindows); // Ahem-based tests don't yet quite work on Windows

  test('changing color does not do layout', () {
    final RenderParagraph paragraph = new RenderParagraph(
      const TextSpan(
        text: 'Hello',
        style: const TextStyle(color: const Color(0xFF000000)),
      ),
      textDirection: TextDirection.ltr,
    );
    layout(paragraph, constraints: const BoxConstraints(maxWidth: 100.0), phase: EnginePhase.paint);
    expect(paragraph.debugNeedsLayout, isFalse);
    expect(paragraph.debugNeedsPaint, isFalse);
    paragraph.text = const TextSpan(
      text: 'Hello World',
      style: const TextStyle(color: const Color(0xFF000000)),
    );
    expect(paragraph.debugNeedsLayout, isTrue);
    expect(paragraph.debugNeedsPaint, isFalse);
    pumpFrame(phase: EnginePhase.paint);
    expect(paragraph.debugNeedsLayout, isFalse);
    expect(paragraph.debugNeedsPaint, isFalse);
    paragraph.text = const TextSpan(
      text: 'Hello World',
      style: const TextStyle(color: const Color(0xFFFFFFFF)),
    );
    expect(paragraph.debugNeedsLayout, isFalse);
    expect(paragraph.debugNeedsPaint, isTrue);
    pumpFrame(phase: EnginePhase.paint);
    expect(paragraph.debugNeedsLayout, isFalse);
    expect(paragraph.debugNeedsPaint, isFalse);
  });

  test('nested TextSpans in paragraph handle textScaleFactor correctly.', () {
    const TextSpan testSpan = const TextSpan(
      text: 'a',
      style: const TextStyle(
        fontSize: 10.0,
      ),
      children: const <TextSpan>[
        const TextSpan(
          text: 'b',
          children: const <TextSpan>[
            const TextSpan(text: 'c'),
          ],
          style: const TextStyle(
            fontSize: 20.0,
          ),
        ),
        const TextSpan(
          text: 'd',
        ),
      ],
    );
    final RenderParagraph paragraph = new RenderParagraph(
        testSpan,
        textDirection: TextDirection.ltr,
        textScaleFactor: 1.3
    );
    paragraph.layout(const BoxConstraints());
    // anyOf is needed here because Linux and Mac have different text
    // rendering widths in tests.
    // TODO(#12357): Figure out why this is, and fix it (if needed) once Blink
    // text rendering is replaced.
    expect(paragraph.size.width, anyOf(79.0, 78.0));
    expect(paragraph.size.height, 26.0);

    // Test the sizes of nested spans.
    final List<ui.TextBox> boxes = <ui.TextBox>[];
    final String text = testSpan.toStringDeep();
    for (int i = 0; i < text.length; ++i) {
      boxes.addAll(paragraph.getBoxesForSelection(
          new TextSelection(baseOffset: i, extentOffset: i + 1)
      ));
    }
    expect(boxes.length, equals(4));

    // anyOf is needed here and below because Linux and Mac have different text
    // rendering widths in tests.
    // TODO(#12357): Figure out why this is, and fix it (if needed) once Blink
    // text rendering is replaced.
    expect(boxes[0].toRect().width, anyOf(14.0, 13.0));
    expect(boxes[0].toRect().height, closeTo(13.0, 0.0001));
    expect(boxes[1].toRect().width, anyOf(27.0, 26.0));
    expect(boxes[1].toRect().height, closeTo(26.0, 0.0001));
    expect(boxes[2].toRect().width, anyOf(27.0, 26.0));
    expect(boxes[2].toRect().height, closeTo(26.0, 0.0001));
    expect(boxes[3].toRect().width, anyOf(14.0, 13.0));
    expect(boxes[3].toRect().height, closeTo(13.0, 0.0001));
  });

  test('toStringDeep', () {
    final RenderParagraph paragraph = new RenderParagraph(
      const TextSpan(text: _kText),
      textDirection: TextDirection.ltr,
      locale: const Locale('ja', 'JP'),
    );
    expect(paragraph, hasAGoodToStringDeep);
    expect(
      paragraph.toStringDeep(minLevel: DiagnosticLevel.info),
      equalsIgnoringHashCodes(
        'RenderParagraph#00000 NEEDS-LAYOUT NEEDS-PAINT DETACHED\n'
        ' │ parentData: MISSING\n'
        ' │ constraints: MISSING\n'
        ' │ size: MISSING\n'
        ' │ textAlign: start\n'
        ' │ textDirection: ltr\n'
        ' │ softWrap: wrapping at box width\n'
        ' │ overflow: clip\n'
        ' │ locale: ja_JP\n'
        ' │ maxLines: unlimited\n'
        ' ╘═╦══ text ═══\n'
        '   ║ TextSpan:\n'
        '   ║   "I polished up that handle so carefullee\n'
        '   ║   That now I am the Ruler of the Queen\'s Navee!"\n'
        '   ╚═══════════\n'
      ),
    );
  });

  test('locale setter', () {
    // Regression test for https://github.com/flutter/flutter/issues/18175

    final RenderParagraph paragraph = new RenderParagraph(
      const TextSpan(text: _kText),
      locale: const Locale('zh', 'HK'),
      textDirection: TextDirection.ltr,
    );
    expect(paragraph.locale, const Locale('zh', 'HK'));

    paragraph.locale = const Locale('ja', 'JP');
    expect(paragraph.locale, const Locale('ja', 'JP'));
  });

}