73 lines
2.1 KiB
Dart
73 lines
2.1 KiB
Dart
import 'dart:io';
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import 'dart:math' as math;
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import 'dart:typed_data';
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import 'dart:ui' as ui;
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import 'package:flutter/material.dart';
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import 'package:path_provider/path_provider.dart';
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class ImageUtils {
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/// 将图片裁剪成圆形，返回 PNG 文件路径
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/// [imageFile] 或 [imageData] 二选一
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static Future<String> toCircleImageFile({
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Uint8List? imageData,
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File? imageFile,
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}) async {
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if (imageData == null && imageFile == null) {
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throw ArgumentError('必须提供 imageData 或 imageFile');
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}
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// 读取原始字节
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final bytes = imageData ?? await imageFile!.readAsBytes();
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// 1. 解码图片
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final codec = await ui.instantiateImageCodec(bytes);
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final frame = await codec.getNextFrame();
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final original = frame.image;
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final width = original.width;
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final height = original.height;
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final size = math.min(width, height);
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// 2. 画布
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final recorder = ui.PictureRecorder();
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final canvas = Canvas(recorder);
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final paint = Paint()..isAntiAlias = true;
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// 3. 圆形遮罩
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final center = Offset(size / 2, size / 2);
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canvas.drawCircle(center, size / 2, paint..color = Colors.white);
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// 4. 设置混合模式为 srcIn
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paint.blendMode = BlendMode.srcIn;
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// 5. 绘制原图（取正方形区域，保证圆形不变形）
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final srcRect = Rect.fromLTWH(
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(width - size) / 2,
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(height - size) / 2,
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size.toDouble(),
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size.toDouble(),
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);
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final dstRect = Rect.fromLTWH(0, 0, size.toDouble(), size.toDouble());
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canvas.drawImageRect(original, srcRect, dstRect, paint);
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// 6. 导出为 Image
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final picture = recorder.endRecording();
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final imgFinal = await picture.toImage(size, size);
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// 7. 转 PNG 字节
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final byteData = await imgFinal.toByteData(format: ui.ImageByteFormat.png);
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final pngBytes = byteData!.buffer.asUint8List();
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// 8. 存临时文件
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final tempDir = await getTemporaryDirectory();
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final file = File(
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'${tempDir.path}/circle_${DateTime.now().millisecondsSinceEpoch}.png',
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);
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await file.writeAsBytes(pngBytes);
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return file.path;
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}
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}
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