| // 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:math' as math; |
| |
| import 'package:ui/ui.dart' as ui; |
| |
| import '../browser_detection.dart'; |
| import '../dom.dart'; |
| import '../embedder.dart'; |
| import '../util.dart'; |
| import 'canvas_paragraph.dart'; |
| import 'layout_fragmenter.dart'; |
| import 'ruler.dart'; |
| |
| class EngineLineMetrics implements ui.LineMetrics { |
| const EngineLineMetrics({ |
| required this.hardBreak, |
| required this.ascent, |
| required this.descent, |
| required this.unscaledAscent, |
| required this.height, |
| required this.width, |
| required this.left, |
| required this.baseline, |
| required this.lineNumber, |
| }); |
| |
| @override |
| final bool hardBreak; |
| |
| @override |
| final double ascent; |
| |
| @override |
| final double descent; |
| |
| @override |
| final double unscaledAscent; |
| |
| @override |
| final double height; |
| |
| @override |
| final double width; |
| |
| @override |
| final double left; |
| |
| @override |
| final double baseline; |
| |
| @override |
| final int lineNumber; |
| |
| @override |
| int get hashCode => Object.hash( |
| hardBreak, |
| ascent, |
| descent, |
| unscaledAscent, |
| height, |
| width, |
| left, |
| baseline, |
| lineNumber, |
| ); |
| |
| @override |
| bool operator ==(Object other) { |
| if (identical(this, other)) { |
| return true; |
| } |
| if (other.runtimeType != runtimeType) { |
| return false; |
| } |
| return other is EngineLineMetrics && |
| other.hardBreak == hardBreak && |
| other.ascent == ascent && |
| other.descent == descent && |
| other.unscaledAscent == unscaledAscent && |
| other.height == height && |
| other.width == width && |
| other.left == left && |
| other.baseline == baseline && |
| other.lineNumber == lineNumber; |
| } |
| |
| @override |
| String toString() { |
| if (assertionsEnabled) { |
| return 'LineMetrics(hardBreak: $hardBreak, ' |
| 'ascent: $ascent, ' |
| 'descent: $descent, ' |
| 'unscaledAscent: $unscaledAscent, ' |
| 'height: $height, ' |
| 'width: $width, ' |
| 'left: $left, ' |
| 'baseline: $baseline, ' |
| 'lineNumber: $lineNumber)'; |
| } else { |
| return super.toString(); |
| } |
| } |
| } |
| |
| class ParagraphLine { |
| ParagraphLine({ |
| required bool hardBreak, |
| required double ascent, |
| required double descent, |
| required double height, |
| required double width, |
| required double left, |
| required double baseline, |
| required int lineNumber, |
| required this.startIndex, |
| required this.endIndex, |
| required this.trailingNewlines, |
| required this.trailingSpaces, |
| required this.spaceCount, |
| required this.widthWithTrailingSpaces, |
| required this.fragments, |
| required this.textDirection, |
| this.displayText, |
| }) : assert(trailingNewlines <= endIndex - startIndex), |
| lineMetrics = EngineLineMetrics( |
| hardBreak: hardBreak, |
| ascent: ascent, |
| descent: descent, |
| unscaledAscent: ascent, |
| height: height, |
| width: width, |
| left: left, |
| baseline: baseline, |
| lineNumber: lineNumber, |
| ); |
| |
| /// Metrics for this line of the paragraph. |
| final EngineLineMetrics lineMetrics; |
| |
| /// The index (inclusive) in the text where this line begins. |
| final int startIndex; |
| |
| /// The index (exclusive) in the text where this line ends. |
| /// |
| /// When the line contains an overflow, then [endIndex] goes until the end of |
| /// the text and doesn't stop at the overflow cutoff. |
| final int endIndex; |
| |
| /// The number of new line characters at the end of the line. |
| final int trailingNewlines; |
| |
| /// The number of spaces at the end of the line. |
| final int trailingSpaces; |
| |
| /// The number of space characters in the entire line. |
| final int spaceCount; |
| |
| /// The full width of the line including all trailing space but not new lines. |
| /// |
| /// The difference between [width] and [widthWithTrailingSpaces] is that |
| /// [widthWithTrailingSpaces] includes trailing spaces in the width |
| /// calculation while [width] doesn't. |
| /// |
| /// For alignment purposes for example, the [width] property is the right one |
| /// to use because trailing spaces shouldn't affect the centering of text. |
| /// But for placing cursors in text fields, we do care about trailing |
| /// spaces so [widthWithTrailingSpaces] is more suitable. |
| final double widthWithTrailingSpaces; |
| |
| /// The fragments that make up this line. |
| final List<LayoutFragment> fragments; |
| |
| /// The text direction of this line, which is the same as the paragraph's. |
| final ui.TextDirection textDirection; |
| |
| /// The text to be rendered on the screen representing this line. |
| final String? displayText; |
| |
| /// The number of space characters in the line excluding trailing spaces. |
| int get nonTrailingSpaces => spaceCount - trailingSpaces; |
| |
| // Convenient getters for line metrics properties. |
| |
| bool get hardBreak => lineMetrics.hardBreak; |
| double get ascent => lineMetrics.ascent; |
| double get descent => lineMetrics.descent; |
| double get unscaledAscent => lineMetrics.unscaledAscent; |
| double get height => lineMetrics.height; |
| double get width => lineMetrics.width; |
| double get left => lineMetrics.left; |
| double get baseline => lineMetrics.baseline; |
| int get lineNumber => lineMetrics.lineNumber; |
| |
| bool overlapsWith(int startIndex, int endIndex) { |
| return startIndex < this.endIndex && this.startIndex < endIndex; |
| } |
| |
| String getText(CanvasParagraph paragraph) { |
| final StringBuffer buffer = StringBuffer(); |
| for (final LayoutFragment fragment in fragments) { |
| buffer.write(fragment.getText(paragraph)); |
| } |
| return buffer.toString(); |
| } |
| |
| @override |
| int get hashCode => Object.hash( |
| lineMetrics, |
| startIndex, |
| endIndex, |
| trailingNewlines, |
| trailingSpaces, |
| spaceCount, |
| widthWithTrailingSpaces, |
| fragments, |
| textDirection, |
| displayText, |
| ); |
| |
| @override |
| bool operator ==(Object other) { |
| if (identical(this, other)) { |
| return true; |
| } |
| if (other.runtimeType != runtimeType) { |
| return false; |
| } |
| return other is ParagraphLine && |
| other.lineMetrics == lineMetrics && |
| other.startIndex == startIndex && |
| other.endIndex == endIndex && |
| other.trailingNewlines == trailingNewlines && |
| other.trailingSpaces == trailingSpaces && |
| other.spaceCount == spaceCount && |
| other.widthWithTrailingSpaces == widthWithTrailingSpaces && |
| other.fragments == fragments && |
| other.textDirection == textDirection && |
| other.displayText == displayText; |
| } |
| |
| @override |
| String toString() { |
| return '$ParagraphLine($startIndex, $endIndex, $lineMetrics)'; |
| } |
| } |
| |
| /// The web implementation of [ui.ParagraphStyle]. |
| class EngineParagraphStyle implements ui.ParagraphStyle { |
| /// Creates a new instance of [EngineParagraphStyle]. |
| EngineParagraphStyle({ |
| this.textAlign, |
| this.textDirection, |
| this.maxLines, |
| this.fontFamily, |
| this.fontSize, |
| this.height, |
| ui.TextHeightBehavior? textHeightBehavior, |
| this.fontWeight, |
| this.fontStyle, |
| ui.StrutStyle? strutStyle, |
| this.ellipsis, |
| this.locale, |
| }) : _textHeightBehavior = textHeightBehavior, |
| // TODO(mdebbar): add support for strut style., b/128317744 |
| _strutStyle = strutStyle as EngineStrutStyle?; |
| |
| final ui.TextAlign? textAlign; |
| final ui.TextDirection? textDirection; |
| final ui.FontWeight? fontWeight; |
| final ui.FontStyle? fontStyle; |
| final int? maxLines; |
| final String? fontFamily; |
| final double? fontSize; |
| final double? height; |
| final ui.TextHeightBehavior? _textHeightBehavior; |
| final EngineStrutStyle? _strutStyle; |
| final String? ellipsis; |
| final ui.Locale? locale; |
| |
| // The effective style attributes should be consistent with paragraph_style.h. |
| ui.TextAlign get effectiveTextAlign => textAlign ?? ui.TextAlign.start; |
| ui.TextDirection get effectiveTextDirection => |
| textDirection ?? ui.TextDirection.ltr; |
| |
| double? get lineHeight { |
| // TODO(mdebbar): Implement proper support for strut styles. |
| // https://github.com/flutter/flutter/issues/32243 |
| final EngineStrutStyle? strutStyle = _strutStyle; |
| final double? strutHeight = strutStyle?._height; |
| if (strutStyle == null || strutHeight == null || strutHeight == 0) { |
| // When there's no strut height, always use paragraph style height. |
| return height; |
| } |
| if (strutStyle._forceStrutHeight ?? false) { |
| // When strut height is forced, ignore paragraph style height. |
| return strutHeight; |
| } |
| // In this case, strut height acts as a minimum height for all parts of the |
| // paragraph. So we take the max of strut height and paragraph style height. |
| return math.max(strutHeight, height ?? 0.0); |
| } |
| |
| @override |
| bool operator ==(Object other) { |
| if (identical(this, other)) { |
| return true; |
| } |
| if (other.runtimeType != runtimeType) { |
| return false; |
| } |
| return other is EngineParagraphStyle && |
| other.textAlign == textAlign && |
| other.textDirection == textDirection && |
| other.fontWeight == fontWeight && |
| other.fontStyle == fontStyle && |
| other.maxLines == maxLines && |
| other.fontFamily == fontFamily && |
| other.fontSize == fontSize && |
| other.height == height && |
| other._textHeightBehavior == _textHeightBehavior && |
| other.ellipsis == ellipsis && |
| other.locale == locale; |
| } |
| |
| @override |
| int get hashCode { |
| return Object.hash( |
| textAlign, |
| textDirection, |
| fontWeight, |
| fontStyle, |
| maxLines, |
| fontFamily, |
| fontSize, |
| height, |
| _textHeightBehavior, |
| ellipsis, |
| locale); |
| } |
| |
| @override |
| String toString() { |
| if (assertionsEnabled) { |
| final double? fontSize = this.fontSize; |
| final double? height = this.height; |
| return 'ParagraphStyle(' |
| 'textAlign: ${textAlign ?? "unspecified"}, ' |
| 'textDirection: ${textDirection ?? "unspecified"}, ' |
| 'fontWeight: ${fontWeight ?? "unspecified"}, ' |
| 'fontStyle: ${fontStyle ?? "unspecified"}, ' |
| 'maxLines: ${maxLines ?? "unspecified"}, ' |
| 'textHeightBehavior: ${_textHeightBehavior ?? "unspecified"}, ' |
| 'fontFamily: ${fontFamily ?? "unspecified"}, ' |
| 'fontSize: ${fontSize != null ? fontSize.toStringAsFixed(1) : "unspecified"}, ' |
| 'height: ${height != null ? "${height.toStringAsFixed(1)}x" : "unspecified"}, ' |
| 'ellipsis: ${ellipsis != null ? '"$ellipsis"' : "unspecified"}, ' |
| 'locale: ${locale ?? "unspecified"}' |
| ')'; |
| } else { |
| return super.toString(); |
| } |
| } |
| } |
| |
| /// The web implementation of [ui.TextStyle]. |
| class EngineTextStyle implements ui.TextStyle { |
| /// Constructs an [EngineTextStyle] with all properties being required. |
| /// |
| /// This is good for call sites that need to be updated whenever a new |
| /// property is added to [EngineTextStyle]. Non-updated call sites will fail |
| /// the build otherwise. |
| factory EngineTextStyle({ |
| required ui.Color? color, |
| required ui.TextDecoration? decoration, |
| required ui.Color? decorationColor, |
| required ui.TextDecorationStyle? decorationStyle, |
| required double? decorationThickness, |
| required ui.FontWeight? fontWeight, |
| required ui.FontStyle? fontStyle, |
| required ui.TextBaseline? textBaseline, |
| required String? fontFamily, |
| required List<String>? fontFamilyFallback, |
| required double? fontSize, |
| required double? letterSpacing, |
| required double? wordSpacing, |
| required double? height, |
| required ui.Locale? locale, |
| required ui.Paint? background, |
| required ui.Paint? foreground, |
| required List<ui.Shadow>? shadows, |
| required List<ui.FontFeature>? fontFeatures, |
| required List<ui.FontVariation>? fontVariations, |
| }) = EngineTextStyle.only; |
| |
| /// Constructs an [EngineTextStyle] with only the given properties. |
| /// |
| /// This constructor should be used sparingly in tests, for example. Or when |
| /// we know for sure that not all properties are needed. |
| EngineTextStyle.only({ |
| this.color, |
| this.decoration, |
| this.decorationColor, |
| this.decorationStyle, |
| this.decorationThickness, |
| this.fontWeight, |
| this.fontStyle, |
| this.textBaseline, |
| String? fontFamily, |
| this.fontFamilyFallback, |
| this.fontSize, |
| this.letterSpacing, |
| this.wordSpacing, |
| this.height, |
| this.locale, |
| this.background, |
| this.foreground, |
| this.shadows, |
| this.fontFeatures, |
| this.fontVariations, |
| }) : assert( |
| color == null || foreground == null, |
| 'Cannot provide both a color and a foreground\n' |
| 'The color argument is just a shorthand for "foreground: Paint()..color = color".'), |
| isFontFamilyProvided = fontFamily != null, |
| fontFamily = fontFamily ?? ''; |
| |
| /// Constructs an [EngineTextStyle] by reading properties from an |
| /// [EngineParagraphStyle]. |
| factory EngineTextStyle.fromParagraphStyle( |
| EngineParagraphStyle paragraphStyle, |
| ) { |
| return EngineTextStyle.only( |
| fontWeight: paragraphStyle.fontWeight, |
| fontStyle: paragraphStyle.fontStyle, |
| fontFamily: paragraphStyle.fontFamily, |
| fontSize: paragraphStyle.fontSize, |
| height: paragraphStyle.height, |
| locale: paragraphStyle.locale, |
| ); |
| } |
| |
| final ui.Color? color; |
| final ui.TextDecoration? decoration; |
| final ui.Color? decorationColor; |
| final ui.TextDecorationStyle? decorationStyle; |
| final double? decorationThickness; |
| final ui.FontWeight? fontWeight; |
| final ui.FontStyle? fontStyle; |
| final ui.TextBaseline? textBaseline; |
| final bool isFontFamilyProvided; |
| final String fontFamily; |
| final List<String>? fontFamilyFallback; |
| final List<ui.FontFeature>? fontFeatures; |
| final List<ui.FontVariation>? fontVariations; |
| final double? fontSize; |
| final double? letterSpacing; |
| final double? wordSpacing; |
| final double? height; |
| final ui.Locale? locale; |
| final ui.Paint? background; |
| final ui.Paint? foreground; |
| final List<ui.Shadow>? shadows; |
| |
| String get effectiveFontFamily { |
| if (assertionsEnabled) { |
| // In the flutter tester environment, we use a predictable-size font |
| // "Ahem". This makes widget tests predictable and less flaky. |
| if (ui.debugEmulateFlutterTesterEnvironment) { |
| return 'Ahem'; |
| } |
| } |
| if (fontFamily.isEmpty) { |
| return FlutterViewEmbedder.defaultFontFamily; |
| } |
| return fontFamily; |
| } |
| |
| String? _cssFontString; |
| |
| /// Font string to be used in CSS. |
| /// |
| /// See <https://developer.mozilla.org/en-US/docs/Web/CSS/font>. |
| String get cssFontString { |
| return _cssFontString ??= buildCssFontString( |
| fontStyle: fontStyle, |
| fontWeight: fontWeight, |
| fontSize: fontSize, |
| fontFamily: effectiveFontFamily, |
| ); |
| } |
| |
| late final TextHeightStyle heightStyle = _createHeightStyle(); |
| |
| TextHeightStyle _createHeightStyle() { |
| return TextHeightStyle( |
| fontFamily: effectiveFontFamily, |
| fontSize: fontSize ?? FlutterViewEmbedder.defaultFontSize, |
| height: height, |
| // TODO(mdebbar): Pass the actual value when font features become supported |
| // https://github.com/flutter/flutter/issues/64595 |
| fontFeatures: null, |
| fontVariations: null, |
| ); |
| } |
| |
| EngineTextStyle copyWith({ |
| ui.Color? color, |
| ui.TextDecoration? decoration, |
| ui.Color? decorationColor, |
| ui.TextDecorationStyle? decorationStyle, |
| double? decorationThickness, |
| ui.FontWeight? fontWeight, |
| ui.FontStyle? fontStyle, |
| ui.TextBaseline? textBaseline, |
| String? fontFamily, |
| List<String>? fontFamilyFallback, |
| double? fontSize, |
| double? letterSpacing, |
| double? wordSpacing, |
| double? height, |
| ui.Locale? locale, |
| ui.Paint? background, |
| ui.Paint? foreground, |
| List<ui.Shadow>? shadows, |
| List<ui.FontFeature>? fontFeatures, |
| List<ui.FontVariation>? fontVariations, |
| }) { |
| return EngineTextStyle( |
| color: color ?? this.color, |
| decoration: decoration ?? this.decoration, |
| decorationColor: decorationColor ?? this.decorationColor, |
| decorationStyle: decorationStyle ?? this.decorationStyle, |
| decorationThickness: decorationThickness ?? this.decorationThickness, |
| fontWeight: fontWeight ?? this.fontWeight, |
| fontStyle: fontStyle ?? this.fontStyle, |
| textBaseline: textBaseline ?? this.textBaseline, |
| fontFamily: fontFamily ?? this.fontFamily, |
| fontFamilyFallback: fontFamilyFallback ?? this.fontFamilyFallback, |
| fontSize: fontSize ?? this.fontSize, |
| letterSpacing: letterSpacing ?? this.letterSpacing, |
| wordSpacing: wordSpacing ?? this.wordSpacing, |
| height: height ?? this.height, |
| locale: locale ?? this.locale, |
| background: background ?? this.background, |
| foreground: foreground ?? this.foreground, |
| shadows: shadows ?? this.shadows, |
| fontFeatures: fontFeatures ?? this.fontFeatures, |
| fontVariations: fontVariations ?? this.fontVariations, |
| ); |
| } |
| |
| @override |
| bool operator ==(Object other) { |
| if (identical(this, other)) { |
| return true; |
| } |
| if (other.runtimeType != runtimeType) { |
| return false; |
| } |
| return other is EngineTextStyle && |
| other.color == color && |
| other.decoration == decoration && |
| other.decorationColor == decorationColor && |
| other.decorationStyle == decorationStyle && |
| other.fontWeight == fontWeight && |
| other.fontStyle == fontStyle && |
| other.textBaseline == textBaseline && |
| other.fontFamily == fontFamily && |
| other.fontSize == fontSize && |
| other.letterSpacing == letterSpacing && |
| other.wordSpacing == wordSpacing && |
| other.height == height && |
| other.locale == locale && |
| other.background == background && |
| other.foreground == foreground && |
| listEquals<ui.Shadow>(other.shadows, shadows) && |
| listEquals<String>(other.fontFamilyFallback, fontFamilyFallback); |
| } |
| |
| @override |
| int get hashCode => Object.hash( |
| color, |
| decoration, |
| decorationColor, |
| decorationStyle, |
| decorationThickness, |
| fontWeight, |
| fontStyle, |
| textBaseline, |
| fontFamily, |
| fontFamilyFallback, |
| fontSize, |
| letterSpacing, |
| wordSpacing, |
| height, |
| locale, |
| background, |
| foreground, |
| shadows, |
| ); |
| |
| @override |
| String toString() { |
| if (assertionsEnabled) { |
| final List<String>? fontFamilyFallback = this.fontFamilyFallback; |
| final double? fontSize = this.fontSize; |
| final double? height = this.height; |
| return 'TextStyle(' |
| 'color: ${color ?? "unspecified"}, ' |
| 'decoration: ${decoration ?? "unspecified"}, ' |
| 'decorationColor: ${decorationColor ?? "unspecified"}, ' |
| 'decorationStyle: ${decorationStyle ?? "unspecified"}, ' |
| 'decorationThickness: ${decorationThickness ?? "unspecified"}, ' |
| 'fontWeight: ${fontWeight ?? "unspecified"}, ' |
| 'fontStyle: ${fontStyle ?? "unspecified"}, ' |
| 'textBaseline: ${textBaseline ?? "unspecified"}, ' |
| 'fontFamily: ${isFontFamilyProvided && fontFamily != '' ? fontFamily : "unspecified"}, ' |
| 'fontFamilyFallback: ${isFontFamilyProvided && fontFamilyFallback != null && fontFamilyFallback.isNotEmpty ? fontFamilyFallback : "unspecified"}, ' |
| 'fontSize: ${fontSize != null ? fontSize.toStringAsFixed(1) : "unspecified"}, ' |
| 'letterSpacing: ${letterSpacing != null ? "${letterSpacing}x" : "unspecified"}, ' |
| 'wordSpacing: ${wordSpacing != null ? "${wordSpacing}x" : "unspecified"}, ' |
| 'height: ${height != null ? "${height.toStringAsFixed(1)}x" : "unspecified"}, ' |
| 'locale: ${locale ?? "unspecified"}, ' |
| 'background: ${background ?? "unspecified"}, ' |
| 'foreground: ${foreground ?? "unspecified"}, ' |
| 'shadows: ${shadows ?? "unspecified"}, ' |
| 'fontFeatures: ${fontFeatures ?? "unspecified"}, ' |
| 'fontVariations: ${fontVariations ?? "unspecified"}' |
| ')'; |
| } else { |
| return super.toString(); |
| } |
| } |
| } |
| |
| /// The web implementation of [ui.StrutStyle]. |
| class EngineStrutStyle implements ui.StrutStyle { |
| EngineStrutStyle({ |
| String? fontFamily, |
| List<String>? fontFamilyFallback, |
| double? fontSize, |
| double? height, |
| ui.TextLeadingDistribution? leadingDistribution, |
| double? leading, |
| ui.FontWeight? fontWeight, |
| ui.FontStyle? fontStyle, |
| bool? forceStrutHeight, |
| }) : _fontFamily = fontFamily, |
| _fontFamilyFallback = fontFamilyFallback, |
| _fontSize = fontSize, |
| _height = height, |
| _leadingDistribution = leadingDistribution, |
| _leading = leading, |
| _fontWeight = fontWeight, |
| _fontStyle = fontStyle, |
| _forceStrutHeight = forceStrutHeight; |
| |
| final String? _fontFamily; |
| final List<String>? _fontFamilyFallback; |
| final double? _fontSize; |
| final double? _height; |
| final double? _leading; |
| final ui.FontWeight? _fontWeight; |
| final ui.FontStyle? _fontStyle; |
| final bool? _forceStrutHeight; |
| final ui.TextLeadingDistribution? _leadingDistribution; |
| |
| @override |
| bool operator ==(Object other) { |
| if (identical(this, other)) { |
| return true; |
| } |
| if (other.runtimeType != runtimeType) { |
| return false; |
| } |
| return other is EngineStrutStyle && |
| other._fontFamily == _fontFamily && |
| other._fontSize == _fontSize && |
| other._height == _height && |
| other._leading == _leading && |
| other._leadingDistribution == _leadingDistribution && |
| other._fontWeight == _fontWeight && |
| other._fontStyle == _fontStyle && |
| other._forceStrutHeight == _forceStrutHeight && |
| listEquals<String>(other._fontFamilyFallback, _fontFamilyFallback); |
| } |
| |
| @override |
| int get hashCode => Object.hash( |
| _fontFamily, |
| _fontFamilyFallback, |
| _fontSize, |
| _height, |
| _leading, |
| _leadingDistribution, |
| _fontWeight, |
| _fontStyle, |
| _forceStrutHeight, |
| ); |
| } |
| |
| /// Holds information for a placeholder in a paragraph. |
| /// |
| /// [width], [height] and [baselineOffset] are expected to be already scaled. |
| class ParagraphPlaceholder { |
| ParagraphPlaceholder( |
| this.width, |
| this.height, |
| this.alignment, { |
| required this.baselineOffset, |
| required this.baseline, |
| }); |
| |
| /// The scaled width of the placeholder. |
| final double width; |
| |
| /// The scaled height of the placeholder. |
| final double height; |
| |
| /// Specifies how the placeholder rectangle will be vertically aligned with |
| /// the surrounding text. |
| final ui.PlaceholderAlignment alignment; |
| |
| /// When the [alignment] value is [ui.PlaceholderAlignment.baseline], the |
| /// [baselineOffset] indicates the distance from the baseline to the top of |
| /// the placeholder rectangle. |
| final double baselineOffset; |
| |
| /// Dictates whether to use alphabetic or ideographic baseline. |
| final ui.TextBaseline baseline; |
| } |
| |
| /// Converts [fontWeight] to its CSS equivalent value. |
| String? fontWeightToCss(ui.FontWeight? fontWeight) { |
| if (fontWeight == null) { |
| return null; |
| } |
| return fontWeightIndexToCss(fontWeightIndex: fontWeight.index); |
| } |
| |
| String fontWeightIndexToCss({int fontWeightIndex = 3}) { |
| switch (fontWeightIndex) { |
| case 0: |
| return '100'; |
| case 1: |
| return '200'; |
| case 2: |
| return '300'; |
| case 3: |
| return 'normal'; |
| case 4: |
| return '500'; |
| case 5: |
| return '600'; |
| case 6: |
| return 'bold'; |
| case 7: |
| return '800'; |
| case 8: |
| return '900'; |
| } |
| |
| assert(() { |
| throw AssertionError( |
| 'Failed to convert font weight $fontWeightIndex to CSS.', |
| ); |
| }()); |
| |
| return ''; |
| } |
| |
| /// Applies a text [style] to an [element], translating the properties to their |
| /// corresponding CSS equivalents. |
| /// |
| /// If [isSpan] is true, the text element is a span within richtext and |
| /// should not assign effectiveFontFamily if fontFamily was not specified. |
| void applyTextStyleToElement({ |
| required DomHTMLElement element, |
| required EngineTextStyle style, |
| bool isSpan = false, |
| }) { |
| assert(element != null); |
| assert(style != null); |
| bool updateDecoration = false; |
| final DomCSSStyleDeclaration cssStyle = element.style; |
| |
| final ui.Color? color = style.foreground?.color ?? style.color; |
| if (style.foreground?.style == ui.PaintingStyle.stroke) { |
| // When comparing the outputs of the Bitmap Canvas and the DOM |
| // implementation, we have found, that we need to set the background color |
| // of the text to transparent to achieve the same effect as in the Bitmap |
| // Canvas and the Skia Engine where only the text stroke is painted. |
| // If we don't set it here to transparent, the text will inherit the color |
| // of it's parent element. |
| cssStyle.color = 'transparent'; |
| // Use hairline (device pixel when strokeWidth is not specified). |
| final double? strokeWidth = style.foreground?.strokeWidth; |
| final double adaptedWidth = strokeWidth != null && strokeWidth > 0 |
| ? strokeWidth |
| : 1.0 / ui.window.devicePixelRatio; |
| cssStyle.textStroke = '${adaptedWidth}px ${colorToCssString(color)}'; |
| } else if (color != null) { |
| cssStyle.color = colorToCssString(color)!; |
| } |
| final ui.Color? background = style.background?.color; |
| if (background != null) { |
| cssStyle.backgroundColor = colorToCssString(background)!; |
| } |
| final double? fontSize = style.fontSize; |
| if (fontSize != null) { |
| cssStyle.fontSize = '${fontSize.floor()}px'; |
| } |
| if (style.fontWeight != null) { |
| cssStyle.fontWeight = fontWeightToCss(style.fontWeight)!; |
| } |
| if (style.fontStyle != null) { |
| cssStyle.fontStyle = |
| style.fontStyle == ui.FontStyle.normal ? 'normal' : 'italic'; |
| } |
| // For test environment use effectiveFontFamily since we need to |
| // consistently use Ahem font. |
| if (isSpan && !ui.debugEmulateFlutterTesterEnvironment) { |
| cssStyle.fontFamily = canonicalizeFontFamily(style.fontFamily)!; |
| } else { |
| cssStyle.fontFamily = canonicalizeFontFamily(style.effectiveFontFamily)!; |
| } |
| if (style.letterSpacing != null) { |
| cssStyle.letterSpacing = '${style.letterSpacing}px'; |
| } |
| if (style.wordSpacing != null) { |
| cssStyle.wordSpacing = '${style.wordSpacing}px'; |
| } |
| if (style.decoration != null) { |
| updateDecoration = true; |
| } |
| final List<ui.Shadow>? shadows = style.shadows; |
| if (shadows != null) { |
| cssStyle.textShadow = _shadowListToCss(shadows); |
| } |
| |
| if (updateDecoration) { |
| if (style.decoration != null) { |
| final String? textDecoration = |
| _textDecorationToCssString(style.decoration, style.decorationStyle); |
| if (textDecoration != null) { |
| if (browserEngine == BrowserEngine.webkit) { |
| setElementStyle(element, '-webkit-text-decoration', textDecoration); |
| } else { |
| cssStyle.textDecoration = textDecoration; |
| } |
| final ui.Color? decorationColor = style.decorationColor; |
| if (decorationColor != null) { |
| cssStyle.textDecorationColor = colorToCssString(decorationColor)!; |
| } |
| } |
| } |
| } |
| |
| final List<ui.FontFeature>? fontFeatures = style.fontFeatures; |
| if (fontFeatures != null && fontFeatures.isNotEmpty) { |
| cssStyle.fontFeatureSettings = _fontFeatureListToCss(fontFeatures); |
| } |
| |
| final List<ui.FontVariation>? fontVariations = style.fontVariations; |
| if (fontVariations != null && fontVariations.isNotEmpty) { |
| cssStyle.setProperty( |
| 'font-variation-settings', _fontVariationListToCss(fontVariations)); |
| } |
| } |
| |
| String _shadowListToCss(List<ui.Shadow> shadows) { |
| if (shadows.isEmpty) { |
| return ''; |
| } |
| // CSS text-shadow is a comma separated list of shadows. |
| // <offsetx> <offsety> <blur-radius> <color>. |
| // Shadows are applied front-to-back with first shadow on top. |
| // Color is optional. offsetx,y are required. blur-radius is optional as well |
| // and defaults to 0. |
| final StringBuffer sb = StringBuffer(); |
| final int len = shadows.length; |
| for (int i = 0; i < len; i++) { |
| if (i != 0) { |
| sb.write(','); |
| } |
| final ui.Shadow shadow = shadows[i]; |
| sb.write('${shadow.offset.dx}px ${shadow.offset.dy}px ' |
| '${shadow.blurRadius}px ${colorToCssString(shadow.color)}'); |
| } |
| return sb.toString(); |
| } |
| |
| String _fontFeatureListToCss(List<ui.FontFeature> fontFeatures) { |
| assert(fontFeatures.isNotEmpty); |
| |
| // For more details, see: |
| // * https://developer.mozilla.org/en-US/docs/Web/CSS/font-feature-settings |
| final StringBuffer sb = StringBuffer(); |
| final int len = fontFeatures.length; |
| for (int i = 0; i < len; i++) { |
| if (i != 0) { |
| sb.write(','); |
| } |
| final ui.FontFeature fontFeature = fontFeatures[i]; |
| sb.write('"${fontFeature.feature}" ${fontFeature.value}'); |
| } |
| return sb.toString(); |
| } |
| |
| String _fontVariationListToCss(List<ui.FontVariation> fontVariations) { |
| assert(fontVariations.isNotEmpty); |
| |
| final StringBuffer sb = StringBuffer(); |
| final int len = fontVariations.length; |
| for (int i = 0; i < len; i++) { |
| if (i != 0) { |
| sb.write(','); |
| } |
| final ui.FontVariation fontVariation = fontVariations[i]; |
| sb.write('"${fontVariation.axis}" ${fontVariation.value}'); |
| } |
| return sb.toString(); |
| } |
| |
| /// Converts text decoration style to CSS text-decoration-style value. |
| String? _textDecorationToCssString( |
| ui.TextDecoration? decoration, ui.TextDecorationStyle? decorationStyle) { |
| final StringBuffer decorations = StringBuffer(); |
| if (decoration != null) { |
| if (decoration.contains(ui.TextDecoration.underline)) { |
| decorations.write('underline '); |
| } |
| if (decoration.contains(ui.TextDecoration.overline)) { |
| decorations.write('overline '); |
| } |
| if (decoration.contains(ui.TextDecoration.lineThrough)) { |
| decorations.write('line-through '); |
| } |
| } |
| if (decorationStyle != null) { |
| decorations.write(_decorationStyleToCssString(decorationStyle)); |
| } |
| return decorations.isEmpty ? null : decorations.toString(); |
| } |
| |
| String? _decorationStyleToCssString(ui.TextDecorationStyle decorationStyle) { |
| switch (decorationStyle) { |
| case ui.TextDecorationStyle.dashed: |
| return 'dashed'; |
| case ui.TextDecorationStyle.dotted: |
| return 'dotted'; |
| case ui.TextDecorationStyle.double: |
| return 'double'; |
| case ui.TextDecorationStyle.solid: |
| return 'solid'; |
| case ui.TextDecorationStyle.wavy: |
| return 'wavy'; |
| default: |
| return null; |
| } |
| } |
| |
| /// Converts [align] to its corresponding CSS value. |
| /// |
| /// This value is used as the "text-align" CSS property, e.g.: |
| /// |
| /// ```css |
| /// text-align: right; |
| /// ``` |
| String textAlignToCssValue( |
| ui.TextAlign? align, ui.TextDirection textDirection) { |
| switch (align) { |
| case ui.TextAlign.left: |
| return 'left'; |
| case ui.TextAlign.right: |
| return 'right'; |
| case ui.TextAlign.center: |
| return 'center'; |
| case ui.TextAlign.justify: |
| return 'justify'; |
| case ui.TextAlign.end: |
| switch (textDirection) { |
| case ui.TextDirection.ltr: |
| return 'end'; |
| case ui.TextDirection.rtl: |
| return 'left'; |
| } |
| case ui.TextAlign.start: |
| switch (textDirection) { |
| case ui.TextDirection.ltr: |
| return ''; // it's the default |
| case ui.TextDirection.rtl: |
| return 'right'; |
| } |
| case null: |
| // If align is not specified return default. |
| return ''; |
| } |
| } |
