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// 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:ui';
import 'package:litetest/litetest.dart';
void main() {
// Ahem font uses a constant ideographic/alphabetic baseline ratio.
const double kAhemBaselineRatio = 1.25;
test('predictably lays out a single-line paragraph', () {
for (final double fontSize in <double>[10.0, 20.0, 30.0, 40.0]) {
final ParagraphBuilder builder = ParagraphBuilder(ParagraphStyle(
fontFamily: 'Ahem',
fontStyle: FontStyle.normal,
fontWeight: FontWeight.normal,
fontSize: fontSize,
));
builder.addText('Test');
final Paragraph paragraph = builder.build();
paragraph.layout(const ParagraphConstraints(width: 400.0));
expect(paragraph.height, closeTo(fontSize, 0.001));
expect(paragraph.width, closeTo(400.0, 0.001));
expect(paragraph.minIntrinsicWidth, closeTo(fontSize * 4.0, 0.001));
expect(paragraph.maxIntrinsicWidth, closeTo(fontSize * 4.0, 0.001));
expect(paragraph.alphabeticBaseline, closeTo(fontSize * .8, 0.001));
expect(
paragraph.ideographicBaseline,
closeTo(paragraph.alphabeticBaseline * kAhemBaselineRatio, 0.001),
);
}
});
test('predictably lays out a multi-line paragraph', () {
for (final double fontSize in <double>[10.0, 20.0, 30.0, 40.0]) {
final ParagraphBuilder builder = ParagraphBuilder(ParagraphStyle(
fontFamily: 'Ahem',
fontStyle: FontStyle.normal,
fontWeight: FontWeight.normal,
fontSize: fontSize,
));
builder.addText('Test Ahem');
final Paragraph paragraph = builder.build();
paragraph.layout(ParagraphConstraints(width: fontSize * 5.0));
expect(paragraph.height, closeTo(fontSize * 2.0, 0.001)); // because it wraps
expect(paragraph.width, closeTo(fontSize * 5.0, 0.001));
expect(paragraph.minIntrinsicWidth, closeTo(fontSize * 4.0, 0.001));
// TODO(yjbanov): see https://github.com/flutter/flutter/issues/21965
expect(paragraph.maxIntrinsicWidth, closeTo(fontSize * 9.0, 0.001));
expect(paragraph.alphabeticBaseline, closeTo(fontSize * .8, 0.001));
expect(
paragraph.ideographicBaseline,
closeTo(paragraph.alphabeticBaseline * kAhemBaselineRatio, 0.001),
);
}
});
test('getLineBoundary', () {
const double fontSize = 10.0;
final ParagraphBuilder builder = ParagraphBuilder(ParagraphStyle(
fontFamily: 'Ahem',
fontStyle: FontStyle.normal,
fontWeight: FontWeight.normal,
fontSize: fontSize,
));
builder.addText('Test Ahem');
final Paragraph paragraph = builder.build();
paragraph.layout(const ParagraphConstraints(width: fontSize * 5.0));
// Wraps to two lines.
expect(paragraph.height, closeTo(fontSize * 2.0, 0.001));
const TextPosition wrapPositionDown = TextPosition(
offset: 5,
);
TextRange line = paragraph.getLineBoundary(wrapPositionDown);
expect(line.start, 5);
expect(line.end, 9);
const TextPosition wrapPositionUp = TextPosition(
offset: 5,
affinity: TextAffinity.upstream,
);
line = paragraph.getLineBoundary(wrapPositionUp);
expect(line.start, 0);
expect(line.end, 5);
const TextPosition wrapPositionStart = TextPosition(
offset: 0,
);
line = paragraph.getLineBoundary(wrapPositionStart);
expect(line.start, 0);
expect(line.end, 5);
const TextPosition wrapPositionEnd = TextPosition(
offset: 9,
);
line = paragraph.getLineBoundary(wrapPositionEnd);
expect(line.start, 5);
expect(line.end, 9);
});
test('getLineBoundary RTL', () {
const double fontSize = 10.0;
final ParagraphBuilder builder = ParagraphBuilder(ParagraphStyle(
fontFamily: 'Ahem',
fontStyle: FontStyle.normal,
fontWeight: FontWeight.normal,
fontSize: fontSize,
textDirection: TextDirection.rtl,
));
builder.addText('القاهرةالقاهرة');
final Paragraph paragraph = builder.build();
paragraph.layout(const ParagraphConstraints(width: fontSize * 5.0));
// Wraps to three lines.
expect(paragraph.height, closeTo(fontSize * 3.0, 0.001));
const TextPosition wrapPositionDown = TextPosition(
offset: 5,
);
TextRange line = paragraph.getLineBoundary(wrapPositionDown);
expect(line.start, 5);
expect(line.end, 10);
const TextPosition wrapPositionUp = TextPosition(
offset: 5,
affinity: TextAffinity.upstream,
);
line = paragraph.getLineBoundary(wrapPositionUp);
expect(line.start, 0);
expect(line.end, 5);
const TextPosition wrapPositionStart = TextPosition(
offset: 0,
);
line = paragraph.getLineBoundary(wrapPositionStart);
expect(line.start, 0);
expect(line.end, 5);
const TextPosition wrapPositionEnd = TextPosition(
offset: 9,
);
line = paragraph.getLineBoundary(wrapPositionEnd);
expect(line.start, 5);
expect(line.end, 10);
});
test('getLineBoundary empty line', () {
const double fontSize = 10.0;
final ParagraphBuilder builder = ParagraphBuilder(ParagraphStyle(
fontFamily: 'Ahem',
fontStyle: FontStyle.normal,
fontWeight: FontWeight.normal,
fontSize: fontSize,
textDirection: TextDirection.rtl,
));
builder.addText('Test\n\nAhem');
final Paragraph paragraph = builder.build();
paragraph.layout(const ParagraphConstraints(width: fontSize * 5.0));
// Three lines due to line breaks, with the middle line being empty.
expect(paragraph.height, closeTo(fontSize * 3.0, 0.001));
const TextPosition emptyLinePosition = TextPosition(
offset: 5,
);
TextRange line = paragraph.getLineBoundary(emptyLinePosition);
expect(line.start, 5);
expect(line.end, 5);
// Since these are hard newlines, TextAffinity has no effect here.
const TextPosition emptyLinePositionUpstream = TextPosition(
offset: 5,
affinity: TextAffinity.upstream,
);
line = paragraph.getLineBoundary(emptyLinePositionUpstream);
expect(line.start, 5);
expect(line.end, 5);
const TextPosition endOfFirstLinePosition = TextPosition(
offset: 4,
);
line = paragraph.getLineBoundary(endOfFirstLinePosition);
expect(line.start, 0);
expect(line.end, 4);
const TextPosition startOfLastLinePosition = TextPosition(
offset: 6,
);
line = paragraph.getLineBoundary(startOfLastLinePosition);
expect(line.start, 6);
expect(line.end, 10);
});
}