138 lines
3.9 KiB
Dart
138 lines
3.9 KiB
Dart
import 'dart:ui' as ui;
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import 'package:flutter/cupertino.dart';
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import 'package:flutter/material.dart';
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import 'package:flutter/services.dart';
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import '../components/coordinate.dart';
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/// create by 张风捷特烈 on 2020-03-19
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/// contact me by email 1981462002@qq.com
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/// 说明: 纸
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class Paper extends StatelessWidget {
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const Paper({super.key});
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@override
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Widget build(BuildContext context) {
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return Container(
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color: Colors.white,
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child: CustomPaint(
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// 使用CustomPaint
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painter: PaperPainter(),
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),
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);
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}
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}
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class PaperPainter extends CustomPainter {
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final Coordinate coordinate = Coordinate();
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late Paint _paint;
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final double strokeWidth = 0.5;
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final Color color = Colors.blue;
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PaperPainter() {
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_paint = Paint()
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..style = PaintingStyle.fill
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..strokeWidth = strokeWidth
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..color = color;
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}
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@override
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void paint(Canvas canvas, Size size) {
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coordinate.paint(canvas, size);
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canvas.translate(size.width / 2, size.height / 2);
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// _drawTextWithParagraph(canvas,TextAlign.left);
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// _drawTextWithParagraph(canvas,TextAlign.center);
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// _drawTextWithParagraph(canvas,TextAlign.right);
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// _drawWithTextPaint(canvas);
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// _drawTextPaintShowSize(canvas);
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_drawTextPaintWithPaint(canvas);
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}
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void _drawTextWithParagraph(Canvas canvas, TextAlign textAlign) {
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var builder = ui.ParagraphBuilder(ui.ParagraphStyle(
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textAlign: textAlign,
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fontSize: 40,
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textDirection: TextDirection.ltr,
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maxLines: 1,
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));
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builder.pushStyle(
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ui.TextStyle(
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color: Colors.black87, textBaseline: ui.TextBaseline.alphabetic),
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);
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builder.addText("Flutter Unit");
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ui.Paragraph paragraph = builder.build();
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paragraph.layout(ui.ParagraphConstraints(width: 300));
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canvas.drawParagraph(paragraph, Offset(0, 0));
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canvas.drawRect(Rect.fromLTRB(0, 0, 300, 40),
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_paint..color = Colors.blue.withAlpha(33));
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}
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void _drawWithTextPaint(Canvas canvas) {
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var textPainter = TextPainter(
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text: TextSpan(
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text: 'Flutter Unit',
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style: TextStyle(fontSize: 40, color: Colors.black)),
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textAlign: TextAlign.center,
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textDirection: TextDirection.ltr);
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// 进行布局
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textPainter.layout();
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textPainter.paint(canvas, Offset.zero);
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}
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void _drawTextPaintShowSize(Canvas canvas) {
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TextPainter textPainter = TextPainter(
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text: TextSpan(
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text: 'Flutter Unit',
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style: TextStyle(
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// foreground: Paint()..style=PaintingStyle.stroke,
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fontSize: 40,
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color: Colors.black)),
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textAlign: TextAlign.center,
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textDirection: TextDirection.ltr);
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textPainter.layout(); // 进行布局
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Size size = textPainter.size; // 尺寸必须在布局后获取
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textPainter.paint(canvas, Offset(-size.width / 2, -size.height / 2));
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canvas.drawRect(
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Rect.fromLTRB(0, 0, size.width, size.height)
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.translate(-size.width / 2, -size.height / 2),
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_paint..color = Colors.blue.withAlpha(33));
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}
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void _drawTextPaintWithPaint(Canvas canvas) {
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Paint textPaint = Paint()
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..style = PaintingStyle.stroke
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..strokeWidth = 1;
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TextPainter textPainter = TextPainter(
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text: TextSpan(
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text: 'Flutter Unit by 张风捷特烈',
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style: TextStyle(
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foreground: textPaint, fontSize: 40)),
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textAlign: TextAlign.center,
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textDirection: TextDirection.ltr);
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textPainter.layout(maxWidth: 280); // 进行布局
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Size size = textPainter.size; // 尺寸必须在布局后获取
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textPainter.paint(canvas, Offset(-size.width / 2, -size.height / 2));
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canvas.drawRect(
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Rect.fromLTRB(0, 0, size.width, size.height)
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.translate(-size.width / 2, -size.height / 2),
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_paint..color = Colors.blue.withAlpha(33));
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}
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@override
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bool shouldRepaint(PaperPainter oldDelegate) => false;
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}
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