80 lines
2.3 KiB
Dart
80 lines
2.3 KiB
Dart
import 'package:flutter/material.dart';
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class FormattedTextController extends TextEditingController {
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final List<Map<String, dynamic>> elements = [];
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FormattedTextController({String? text}) : super(text: text);
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@override
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TextSpan buildTextSpan({
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required BuildContext context,
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TextStyle? style,
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bool withComposing = false,
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}) {
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final baseStyle = style ?? DefaultTextStyle.of(context).style;
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final text = value.text;
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if (text.isEmpty || elements.isEmpty) {
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return TextSpan(text: text, style: baseStyle);
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}
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final bold = List<bool>.filled(text.length, false);
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final italic = List<bool>.filled(text.length, false);
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final underline = List<bool>.filled(text.length, false);
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final strike = List<bool>.filled(text.length, false);
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for (final el in elements) {
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final type = el['type'] as String?;
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final from = (el['from'] as int?) ?? 0;
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final length = (el['length'] as int?) ?? 0;
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if (type == null || length <= 0) continue;
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final start = from.clamp(0, text.length);
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final end = (from + length).clamp(0, text.length);
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for (int i = start; i < end; i++) {
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switch (type) {
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case 'STRONG':
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bold[i] = true;
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break;
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case 'EMPHASIZED':
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italic[i] = true;
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break;
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case 'UNDERLINE':
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underline[i] = true;
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break;
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case 'STRIKETHROUGH':
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strike[i] = true;
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break;
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}
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}
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}
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final spans = <InlineSpan>[];
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int start = 0;
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TextStyle styleForIndex(int i) {
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var s = baseStyle;
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if (bold[i]) s = s.copyWith(fontWeight: FontWeight.w600);
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if (italic[i]) s = s.copyWith(fontStyle: FontStyle.italic);
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final decos = <TextDecoration>[];
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if (underline[i]) decos.add(TextDecoration.underline);
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if (strike[i]) decos.add(TextDecoration.lineThrough);
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if (decos.isNotEmpty) {
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s = s.copyWith(decoration: TextDecoration.combine(decos));
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}
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return s;
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}
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while (start < text.length) {
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int end = start + 1;
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final base = styleForIndex(start);
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while (end < text.length && styleForIndex(end) == base) {
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end++;
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}
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spans.add(TextSpan(text: text.substring(start, end), style: base));
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start = end;
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}
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return TextSpan(style: baseStyle, children: spans);
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}
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}
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