80 lines
1.8 KiB
Dart
80 lines
1.8 KiB
Dart
import 'dart:ui' as ui;
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import 'package:flutter/material.dart';
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import 'package:intl/intl.dart';
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/// 防截屏水印（对应 Android WatermarkUtils）
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class Watermark extends StatelessWidget {
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final String text;
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final int columns;
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final int rows;
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final double rotation;
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const Watermark({
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super.key,
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required this.text,
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this.columns = 4,
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this.rows = 8,
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this.rotation = -0.4,
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});
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@override
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Widget build(BuildContext context) {
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return IgnorePointer(
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ignoring: true,
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child: CustomPaint(
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painter: _WatermarkPainter(
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text: '$text ${DateFormat('yyyy-MM-dd HH:mm').format(DateTime.now())}',
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columns: columns,
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rows: rows,
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rotation: rotation,
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),
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child: const SizedBox.expand(),
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),
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);
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}
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}
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class _WatermarkPainter extends CustomPainter {
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final String text;
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final int columns;
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final int rows;
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final double rotation;
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_WatermarkPainter({
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required this.text,
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required this.columns,
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required this.rows,
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required this.rotation,
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});
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@override
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void paint(Canvas canvas, Size size) {
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final textPainter = TextPainter(
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text: TextSpan(
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text: text,
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style: TextStyle(
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color: Colors.black.withValues(alpha: 0.06),
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fontSize: 14,
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),
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),
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textDirection: ui.TextDirection.ltr,
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)..layout();
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final dx = size.width / columns;
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final dy = size.height / rows;
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for (int i = 0; i <= columns; i++) {
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for (int j = 0; j <= rows; j++) {
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canvas.save();
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canvas.translate(i * dx, j * dy);
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canvas.rotate(rotation);
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textPainter.paint(canvas, const Offset(0, 0));
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canvas.restore();
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}
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}
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}
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@override
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bool shouldRepaint(_WatermarkPainter old) => old.text != text;
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} |