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[web] Respect maxLines when calculating boxes for a range (flutter/engine#16749)

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This commit is contained in:
Mouad Debbar 2020-02-24 14:26:03 -08:00 committed by GitHub
parent 489ddd405b
commit 53dc99cd26
3 changed files with 202 additions and 34 deletions
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8
engine/src/flutter/lib/web_ui/lib/src/engine/text/paragraph.dart
View File

@ -374,6 +374,10 @@ class EngineParagraph implements ui.Paragraph {
}
final List<EngineLineMetrics> lines = _measurementResult.lines;
if (start >= lines.last.endIndex) {
return <ui.TextBox>[];
}
final EngineLineMetrics startLine = _getLineForIndex(start);
EngineLineMetrics endLine = _getLineForIndex(end);
@ -535,8 +539,7 @@ class EngineParagraph implements ui.Paragraph {
EngineLineMetrics _getLineForIndex(int index) {
assert(_hasLineMetrics);
final List<EngineLineMetrics> lines = _measurementResult.lines;
assert(index >= lines.first.startIndex);
assert(index <= lines.last.endIndex);
assert(index >= 0);
for (int i = 0; i < lines.length; i++) {
final EngineLineMetrics line = lines[i];
@ -545,7 +548,6 @@ class EngineParagraph implements ui.Paragraph {
}
}
assert(index == lines.last.endIndex);
return lines.last;
}

16
engine/src/flutter/lib/web_ui/lib/src/engine/text/ruler.dart
View File

@ -733,7 +733,22 @@ class ParagraphRuler {
final List<html.Rectangle<num>> clientRects = rangeSpan.getClientRects();
final List<ui.TextBox> boxes = <ui.TextBox>[];
final double maxLinesLimit = style.maxLines == null
? double.infinity
: style.maxLines * lineHeightDimensions.height;
html.Rectangle<num> previousRect;
for (html.Rectangle<num> rect in clientRects) {
// If [rect] is an empty box on the same line as the previous box, don't
// include it in the result.
if (rect.top == previousRect?.top && rect.left == rect.right) {
continue;
}
// As soon as we go beyond [maxLines], stop adding boxes.
if (rect.top >= maxLinesLimit) {
break;
}
boxes.add(ui.TextBox.fromLTRBD(
rect.left + alignOffset,
rect.top,
@ -741,6 +756,7 @@ class ParagraphRuler {
rect.bottom,
textDirection,
));
previousRect = rect;
}
// Cleanup after measuring the boxes.

212
engine/src/flutter/lib/web_ui/test/paragraph_test.dart
View File

@ -441,11 +441,185 @@ void main() async {
final Paragraph paragraph = builder.build();
paragraph.layout(const ParagraphConstraints(width: 100));
// In the dom-based measurement (except Firefox), there will be some
// discrepancies around line ends.
final isDiscrepancyExpected =
!TextMeasurementService.enableExperimentalCanvasImplementation &&
browserEngine != BrowserEngine.firefox;
// First line: "abcd\n"
// At the beginning of the first line.
expect(
paragraph.getBoxesForRange(0, 0),
<TextBox>[],
);
// At the end of the first line.
expect(
paragraph.getBoxesForRange(4, 4),
<TextBox>[],
);
// Between "b" and "c" in the first line.
expect(
paragraph.getBoxesForRange(2, 2),
<TextBox>[],
);
// The range "ab" in the first line.
expect(
paragraph.getBoxesForRange(0, 2),
<TextBox>[
TextBox.fromLTRBD(0.0, 0.0, 20.0, 10.0, TextDirection.ltr),
],
);
// The range "bc" in the first line.
expect(
paragraph.getBoxesForRange(1, 3),
<TextBox>[
TextBox.fromLTRBD(10.0, 0.0, 30.0, 10.0, TextDirection.ltr),
],
);
// The range "d" in the first line.
expect(
paragraph.getBoxesForRange(3, 4),
<TextBox>[
TextBox.fromLTRBD(30.0, 0.0, 40.0, 10.0, TextDirection.ltr),
],
);
// The range "\n" in the first line.
expect(
paragraph.getBoxesForRange(4, 5),
<TextBox>[
TextBox.fromLTRBD(40.0, 0.0, 40.0, 10.0, TextDirection.ltr),
],
);
// The range "cd\n" in the first line.
expect(
paragraph.getBoxesForRange(2, 5),
<TextBox>[
TextBox.fromLTRBD(20.0, 0.0, 40.0, 10.0, TextDirection.ltr),
],
);
// Second line: "abcdefg\n"
// At the beginning of the second line.
expect(
paragraph.getBoxesForRange(5, 5),
<TextBox>[],
);
// At the end of the second line.
expect(
paragraph.getBoxesForRange(12, 12),
<TextBox>[],
);
// The range "efg" in the second line.
expect(
paragraph.getBoxesForRange(9, 12),
<TextBox>[
TextBox.fromLTRBD(40.0, 10.0, 70.0, 20.0, TextDirection.ltr),
],
);
// The range "bcde" in the second line.
expect(
paragraph.getBoxesForRange(6, 10),
<TextBox>[
TextBox.fromLTRBD(10.0, 10.0, 50.0, 20.0, TextDirection.ltr),
],
);
// The range "fg\n" in the second line.
expect(
paragraph.getBoxesForRange(10, 13),
<TextBox>[
TextBox.fromLTRBD(50.0, 10.0, 70.0, 20.0, TextDirection.ltr),
],
);
// Last (third) line: "ab"
// At the beginning of the last line.
expect(
paragraph.getBoxesForRange(13, 13),
<TextBox>[],
);
// At the end of the last line.
expect(
paragraph.getBoxesForRange(15, 15),
<TextBox>[],
);
// The range "a" in the last line.
expect(
paragraph.getBoxesForRange(14, 15),
<TextBox>[
TextBox.fromLTRBD(10.0, 20.0, 20.0, 30.0, TextDirection.ltr),
],
);
// The range "ab" in the last line.
expect(
paragraph.getBoxesForRange(13, 15),
<TextBox>[
TextBox.fromLTRBD(0.0, 20.0, 20.0, 30.0, TextDirection.ltr),
],
);
// Combine multiple lines
// The range "cd\nabc".
expect(
paragraph.getBoxesForRange(2, 8),
<TextBox>[
TextBox.fromLTRBD(20.0, 0.0, 40.0, 10.0, TextDirection.ltr),
TextBox.fromLTRBD(0.0, 10.0, 30.0, 20.0, TextDirection.ltr),
],
);
// The range "\nabcd".
expect(
paragraph.getBoxesForRange(4, 9),
<TextBox>[
TextBox.fromLTRBD(40.0, 0.0, 40.0, 10.0, TextDirection.ltr),
TextBox.fromLTRBD(0.0, 10.0, 40.0, 20.0, TextDirection.ltr),
],
);
// The range "d\nabcdefg\na".
expect(
paragraph.getBoxesForRange(3, 14),
<TextBox>[
TextBox.fromLTRBD(30.0, 0.0, 40.0, 10.0, TextDirection.ltr),
TextBox.fromLTRBD(0.0, 10.0, 70.0, 20.0, TextDirection.ltr),
TextBox.fromLTRBD(0.0, 20.0, 10.0, 30.0, TextDirection.ltr),
],
);
// The range "abcd\nabcdefg\n".
expect(
paragraph.getBoxesForRange(0, 13),
<TextBox>[
TextBox.fromLTRBD(0.0, 0.0, 40.0, 10.0, TextDirection.ltr),
TextBox.fromLTRBD(0.0, 10.0, 70.0, 20.0, TextDirection.ltr),
],
);
// The range "abcd\nabcdefg\nab".
expect(
paragraph.getBoxesForRange(0, 15),
<TextBox>[
TextBox.fromLTRBD(0.0, 0.0, 40.0, 10.0, TextDirection.ltr),
TextBox.fromLTRBD(0.0, 10.0, 70.0, 20.0, TextDirection.ltr),
TextBox.fromLTRBD(0.0, 20.0, 20.0, 30.0, TextDirection.ltr),
],
);
});
testEachMeasurement('getBoxesForRange with maxLines', () {
final ParagraphBuilder builder = ParagraphBuilder(ParagraphStyle(
fontFamily: 'Ahem',
fontStyle: FontStyle.normal,
fontWeight: FontWeight.normal,
fontSize: 10,
textDirection: TextDirection.ltr,
maxLines: 2,
));
builder.addText('abcd\n');
builder.addText('abcdefg\n');
builder.addText('ab');
final Paragraph paragraph = builder.build();
paragraph.layout(const ParagraphConstraints(width: 100));
// First line: "abcd\n"
@ -497,8 +671,6 @@ void main() async {
paragraph.getBoxesForRange(2, 5),
<TextBox>[
TextBox.fromLTRBD(20.0, 0.0, 40.0, 10.0, TextDirection.ltr),
if (isDiscrepancyExpected)
TextBox.fromLTRBD(40.0, 0.0, 40.0, 10.0, TextDirection.ltr),
],
);
@ -533,8 +705,6 @@ void main() async {
paragraph.getBoxesForRange(10, 13),
<TextBox>[
TextBox.fromLTRBD(50.0, 10.0, 70.0, 20.0, TextDirection.ltr),
if (isDiscrepancyExpected)
TextBox.fromLTRBD(70.0, 10.0, 70.0, 20.0, TextDirection.ltr),
],
);
@ -553,16 +723,12 @@ void main() async {
// The range "a" in the last line.
expect(
paragraph.getBoxesForRange(14, 15),
<TextBox>[
TextBox.fromLTRBD(10.0, 20.0, 20.0, 30.0, TextDirection.ltr),
],
<TextBox>[],
);
// The range "ab" in the last line.
expect(
paragraph.getBoxesForRange(13, 15),
<TextBox>[
TextBox.fromLTRBD(0.0, 20.0, 20.0, 30.0, TextDirection.ltr),
],
<TextBox>[],
);
@ -573,8 +739,6 @@ void main() async {
paragraph.getBoxesForRange(2, 8),
<TextBox>[
TextBox.fromLTRBD(20.0, 0.0, 40.0, 10.0, TextDirection.ltr),
if (isDiscrepancyExpected)
TextBox.fromLTRBD(40.0, 0.0, 40.0, 10.0, TextDirection.ltr),
TextBox.fromLTRBD(0.0, 10.0, 30.0, 20.0, TextDirection.ltr),
],
);
@ -593,12 +757,7 @@ void main() async {
paragraph.getBoxesForRange(3, 14),
<TextBox>[
TextBox.fromLTRBD(30.0, 0.0, 40.0, 10.0, TextDirection.ltr),
if (isDiscrepancyExpected)
TextBox.fromLTRBD(40.0, 0.0, 40.0, 10.0, TextDirection.ltr),
TextBox.fromLTRBD(0.0, 10.0, 70.0, 20.0, TextDirection.ltr),
if (isDiscrepancyExpected)
TextBox.fromLTRBD(70.0, 10.0, 70.0, 20.0, TextDirection.ltr),
TextBox.fromLTRBD(0.0, 20.0, 10.0, 30.0, TextDirection.ltr),
],
);
@ -607,11 +766,7 @@ void main() async {
paragraph.getBoxesForRange(0, 13),
<TextBox>[
TextBox.fromLTRBD(0.0, 0.0, 40.0, 10.0, TextDirection.ltr),
if (isDiscrepancyExpected)
TextBox.fromLTRBD(40.0, 0.0, 40.0, 10.0, TextDirection.ltr),
TextBox.fromLTRBD(0.0, 10.0, 70.0, 20.0, TextDirection.ltr),
if (isDiscrepancyExpected)
TextBox.fromLTRBD(70.0, 10.0, 70.0, 20.0, TextDirection.ltr),
],
);
@ -620,12 +775,7 @@ void main() async {
paragraph.getBoxesForRange(0, 15),
<TextBox>[
TextBox.fromLTRBD(0.0, 0.0, 40.0, 10.0, TextDirection.ltr),
if (isDiscrepancyExpected)
TextBox.fromLTRBD(40.0, 0.0, 40.0, 10.0, TextDirection.ltr),
TextBox.fromLTRBD(0.0, 10.0, 70.0, 20.0, TextDirection.ltr),
if (isDiscrepancyExpected)
TextBox.fromLTRBD(70.0, 10.0, 70.0, 20.0, TextDirection.ltr),
TextBox.fromLTRBD(0.0, 20.0, 20.0, 30.0, TextDirection.ltr),
],
);
});