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Add intrinsic dimensions to RenderEditable (#10093)

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* Make TextPainter.preferredLineHeight honour root fontSize

* Remove bogus docs.

* More aggressively track dirty state for RenderEditable.

* Some tests.
This commit is contained in:
Ian Hickson 2017-05-15 14:06:58 -07:00 committed by GitHub
parent b232a84b0d
commit abeb164fe2
4 changed files with 101 additions and 26 deletions
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33
packages/flutter/lib/src/painting/text_painter.dart
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@ -136,15 +136,30 @@ class TextPainter {
ui.Paragraph _layoutTemplate;
ui.ParagraphStyle _createParagraphStyle() {
return _text.style?.getParagraphStyle(
textAlign: textAlign,
textScaleFactor: textScaleFactor,
maxLines: _maxLines,
ellipsis: _ellipsis,
) ?? new ui.ParagraphStyle(
textAlign: textAlign,
maxLines: maxLines,
ellipsis: ellipsis,
);
}
/// The height of a zero-width space in [text] in logical pixels.
///
/// Not every line of text in [text] will have this height, but this height
/// is "typical" for text in [text] and useful for sizing other objects
/// relative a typical line of text.
///
/// Obtaining this value does not require calling [layout].
double get preferredLineHeight {
assert(text != null);
if (_layoutTemplate == null) {
final ui.ParagraphBuilder builder = new ui.ParagraphBuilder(new ui.ParagraphStyle());
final ui.ParagraphBuilder builder = new ui.ParagraphBuilder(_createParagraphStyle());
if (text.style != null)
builder.pushStyle(text.style.getTextStyle(textScaleFactor: textScaleFactor));
builder.addText(_kZeroWidthSpace);
@ -165,7 +180,8 @@ class TextPainter {
return layoutValue.ceilToDouble();
}
/// The width at which decreasing the width of the text would prevent it from painting itself completely within its bounds.
/// The width at which decreasing the width of the text would prevent it from
/// painting itself completely within its bounds.
///
/// Valid only after [layout] has been called.
double get minIntrinsicWidth {
@ -251,18 +267,7 @@ class TextPainter {
return;
_needsLayout = false;
if (_paragraph == null) {
ui.ParagraphStyle paragraphStyle = _text.style?.getParagraphStyle(
textAlign: textAlign,
textScaleFactor: textScaleFactor,
maxLines: _maxLines,
ellipsis: _ellipsis,
);
paragraphStyle ??= new ui.ParagraphStyle(
textAlign: textAlign,
maxLines: maxLines,
ellipsis: ellipsis,
);
final ui.ParagraphBuilder builder = new ui.ParagraphBuilder(paragraphStyle);
final ui.ParagraphBuilder builder = new ui.ParagraphBuilder(_createParagraphStyle());
_text.build(builder, textScaleFactor: textScaleFactor);
_paragraph = builder.build();
}

58
packages/flutter/lib/src/rendering/editable.dart
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@ -53,9 +53,7 @@ class TextSelectionPoint {
}
}
/// A single line of editable text.
class RenderEditable extends RenderBox {
/// Creates a render object for a single line of editable text.
RenderEditable({
TextSpan text,
TextAlign textAlign,
@ -89,6 +87,18 @@ class RenderEditable extends RenderBox {
/// Called when the selection changes.
SelectionChangedHandler onSelectionChanged;
double _textLayoutLastWidth;
/// Marks the render object as needing to be laid out again and have its text
/// metrics recomputed.
///
/// Implies [markNeedsLayout].
@protected
void markNeedsTextLayout() {
_textLayoutLastWidth = null;
markNeedsLayout();
}
/// The text to display
TextSpan get text => _textPainter.text;
final TextPainter _textPainter;
@ -96,7 +106,7 @@ class RenderEditable extends RenderBox {
if (_textPainter.text == value)
return;
_textPainter.text = value;
markNeedsLayout();
markNeedsTextLayout();
}
/// How the text should be aligned horizontally.
@ -143,7 +153,7 @@ class RenderEditable extends RenderBox {
if (_maxLines == value)
return;
_maxLines = value;
markNeedsLayout();
markNeedsTextLayout();
}
/// The color to use when painting the selection.
@ -166,7 +176,7 @@ class RenderEditable extends RenderBox {
if (_textPainter.textScaleFactor == value)
return;
_textPainter.textScaleFactor = value;
markNeedsLayout();
markNeedsTextLayout();
}
List<ui.TextBox> _selectionRects;
@ -261,10 +271,8 @@ class RenderEditable extends RenderBox {
/// points might actually be co-located (e.g., because of a bidirectional
/// selection that contains some text but whose ends meet in the middle).
List<TextSelectionPoint> getEndpointsForSelection(TextSelection selection) {
// TODO(mpcomplete): We should be more disciplined about when we dirty the
// layout state of the text painter so that we can know that the layout is
// clean at this point.
_layoutText();
assert(constraints != null);
_layoutText(constraints.maxWidth);
final Offset paintOffset = _paintOffset;
@ -286,6 +294,7 @@ class RenderEditable extends RenderBox {
/// Returns the position in the text for the given global coordinate.
TextPosition getPositionForPoint(Offset globalPosition) {
_layoutText(constraints.maxWidth);
globalPosition += -_paintOffset;
return _textPainter.getPositionForOffset(globalToLocal(globalPosition));
}
@ -293,11 +302,25 @@ class RenderEditable extends RenderBox {
/// Returns the Rect in local coordinates for the caret at the given text
/// position.
Rect getLocalRectForCaret(TextPosition caretPosition) {
_layoutText(constraints.maxWidth);
final Offset caretOffset = _textPainter.getOffsetForCaret(caretPosition, _caretPrototype);
// This rect is the same as _caretPrototype but without the vertical padding.
return new Rect.fromLTWH(0.0, 0.0, _kCaretWidth, _preferredLineHeight).shift(caretOffset + _paintOffset);
}
@override
double computeMinIntrinsicWidth(double height) {
_layoutText(double.INFINITY);
return _textPainter.minIntrinsicWidth;
}
@override
double computeMaxIntrinsicWidth(double height) {
_layoutText(double.INFINITY);
return _textPainter.maxIntrinsicWidth;
}
// This does not required the layout to be updated.
double get _preferredLineHeight => _textPainter.preferredLineHeight;
@override
@ -332,6 +355,7 @@ class RenderEditable extends RenderBox {
}
void _handleTap() {
_layoutText(constraints.maxWidth);
assert(_lastTapDownPosition != null);
final Offset globalPosition = _lastTapDownPosition;
_lastTapDownPosition = null;
@ -348,6 +372,7 @@ class RenderEditable extends RenderBox {
}
void _handleLongPress() {
_layoutText(constraints.maxWidth);
final Offset globalPosition = _longPressPosition;
_longPressPosition = null;
if (onSelectionChanged != null) {
@ -357,6 +382,7 @@ class RenderEditable extends RenderBox {
}
TextSelection _selectWordAtOffset(TextPosition position) {
assert(_textLayoutLastWidth == constraints.maxWidth);
final TextRange word = _textPainter.getWordBoundary(position);
// When long-pressing past the end of the text, we want a collapsed cursor.
if (position.offset >= word.end)
@ -366,18 +392,22 @@ class RenderEditable extends RenderBox {
Rect _caretPrototype;
void _layoutText() {
void _layoutText(double constraintWidth) {
assert(constraintWidth != null);
if (_textLayoutLastWidth == constraintWidth)
return;
final double caretMargin = _kCaretGap + _kCaretWidth;
final double availableWidth = math.max(0.0, constraints.maxWidth - caretMargin);
final double availableWidth = math.max(0.0, constraintWidth - caretMargin);
final double maxWidth = _maxLines > 1 ? availableWidth : double.INFINITY;
_textPainter.layout(minWidth: availableWidth, maxWidth: maxWidth);
_textLayoutLastWidth = constraintWidth;
}
@override
void performLayout() {
_layoutText(constraints.maxWidth);
_caretPrototype = new Rect.fromLTWH(0.0, _kCaretHeightOffset, _kCaretWidth, _preferredLineHeight - 2.0 * _kCaretHeightOffset);
_selectionRects = null;
_layoutText();
size = new Size(constraints.maxWidth, constraints.constrainHeight(
_textPainter.height.clamp(_preferredLineHeight, _preferredLineHeight * _maxLines)
));
@ -389,12 +419,14 @@ class RenderEditable extends RenderBox {
}
void _paintCaret(Canvas canvas, Offset effectiveOffset) {
assert(_textLayoutLastWidth == constraints.maxWidth);
final Offset caretOffset = _textPainter.getOffsetForCaret(_selection.extent, _caretPrototype);
final Paint paint = new Paint()..color = _cursorColor;
canvas.drawRect(_caretPrototype.shift(caretOffset + effectiveOffset), paint);
}
void _paintSelection(Canvas canvas, Offset effectiveOffset) {
assert(_textLayoutLastWidth == constraints.maxWidth);
assert(_selectionRects != null);
final Paint paint = new Paint()..color = _selectionColor;
for (ui.TextBox box in _selectionRects)
@ -402,6 +434,7 @@ class RenderEditable extends RenderBox {
}
void _paintContents(PaintingContext context, Offset offset) {
assert(_textLayoutLastWidth == constraints.maxWidth);
final Offset effectiveOffset = offset + _paintOffset;
if (_selection != null) {
@ -418,6 +451,7 @@ class RenderEditable extends RenderBox {
@override
void paint(PaintingContext context, Offset offset) {
_layoutText(constraints.maxWidth);
if (_hasVisualOverflow)
context.pushClipRect(needsCompositing, offset, Offset.zero & size, _paintContents);
else

14
packages/flutter/test/painting/text_painter_test.dart
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@ -48,4 +48,18 @@ void main() {
painter.layout();
expect(painter.size, const Size(123.0, 123.0));
});
test('TextPainter default text height is 14 pixels', () {
final TextPainter painter = new TextPainter(text: const TextSpan(text: 'x'));
painter.layout();
expect(painter.preferredLineHeight, 14.0);
expect(painter.size, const Size(14.0, 14.0));
});
test('TextPainter sets paragraph size from root', () {
final TextPainter painter = new TextPainter(text: const TextSpan(text: 'x', style: const TextStyle(fontSize: 100.0)));
painter.layout();
expect(painter.preferredLineHeight, 100.0);
expect(painter.size, const Size(100.0, 100.0));
});
}

22
packages/flutter/test/rendering/editable_test.dart Normal file
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@ -0,0 +1,22 @@
// Copyright 2017 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/rendering.dart';
import 'package:test/test.dart';
void main() {
test('editable intrinsics', () {
final RenderEditable editable = new RenderEditable(
text: const TextSpan(
style: const TextStyle(height: 1.0, fontSize: 10.0, fontFamily: 'Ahem'),
text: '12345',
),
offset: new ViewportOffset.zero(),
);
expect(editable.getMinIntrinsicWidth(double.INFINITY), 50.0);
expect(editable.getMaxIntrinsicWidth(double.INFINITY), 50.0);
expect(editable.getMinIntrinsicHeight(double.INFINITY), 10.0);
expect(editable.getMaxIntrinsicHeight(double.INFINITY), 10.0);
});
}