我正在尝试从用户那里收集签名并将其保存到图像中。我已经做到了可以在屏幕上绘图的距离,但现在我想单击一个按钮以保存到图像并存储在我的数据库中。
这是我目前所拥有的:
import 'package:flutter/material.dart';
class SignaturePadPage extends StatefulWidget {
SignaturePadPage({Key key}) : super(key: key);
@override
_SignaturePadPage createState() => new _SignaturePadPage();
}
class _SignaturePadPage extends State<SignaturePadPage> {
List<Offset> _points = <Offset>[];
@override
Widget build(BuildContext context) {
return Container(
color: Colors.white,
child: GestureDetector(
onPanUpdate: (DragUpdateDetails details) {
setState(() {
RenderBox referenceBox = context.findRenderObject();
Offset localPosition =
referenceBox.globalToLocal(details.globalPosition);
_points = new List.from(_points)..add(localPosition);
});
},
onPanEnd: (DragEndDetails details) => _points.add(null),
child: new CustomPaint(painter: new SignaturePainter(_points)),
),
);
}
}
class SignaturePainter extends CustomPainter {
SignaturePainter(this.points);
final List<Offset> points;
void paint(Canvas canvas, Size size) {
Paint paint = new Paint()
..color = Colors.black
..strokeCap = StrokeCap.round
..strokeWidth = 5.0;
for (int i = 0; i < points.length - 1; i++) {
if (points[i] != null && points[i + 1] != null)
canvas.drawLine(points[i], points[i + 1], paint);
}
}
bool shouldRepaint(SignaturePainter other) => other.points != points;
}
不知道从那里去哪里......
最佳答案
您可以捕获 CustomPainter
的输出与 PictureRecorder
.通过您的PictureRecorder
Canvas
的构造函数的实例. Picture
由 PictureRecorder.endRecording
返回然后可以转换为 Image
与 Picture.toImage
.最后,使用 Image.toByteData
提取图像字节.
这是一个例子:https://github.com/rxlabz/flutter_canvas_to_image
https://stackoverflow.com/questions/50320479/