在Flutter中向图像添加文本,可以通过使用相应的库和组件来实现。下面是一种常用的方法:
pubspec.yaml
文件中添加以下依赖:dependencies:
flutter:
sdk: flutter
flutter_image:
image_picker:
path_provider:
import 'package:flutter/material.dart';
import 'package:flutter_image/flutter_image.dart';
import 'package:image_picker/image_picker.dart';
import 'package:path_provider/path_provider.dart';
class ImageWithText extends StatefulWidget {
@override
_ImageWithTextState createState() => _ImageWithTextState();
}
class _ImageWithTextState extends State<ImageWithText> {
File _image;
String _text = '';
Future getImage() async {
var image = await ImagePicker.pickImage(source: ImageSource.gallery);
setState(() {
_image = image;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Add Text to Image'),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
_image == null
? Text('No image selected.')
: Image.file(_image),
SizedBox(height: 20),
TextField(
onChanged: (value) {
setState(() {
_text = value;
});
},
decoration: InputDecoration(
hintText: 'Enter text',
),
),
SizedBox(height: 20),
RaisedButton(
onPressed: getImage,
child: Text('Select Image'),
),
SizedBox(height: 20),
RaisedButton(
onPressed: () async {
final directory = await getApplicationDocumentsDirectory();
final imagePath = '${directory.path}/image_with_text.png';
await drawTextOnImage(_image.path, imagePath, _text);
// Use the resulting image with text
// e.g. upload to server or display it
},
child: Text('Add Text'),
),
],
),
),
);
}
Future<void> drawTextOnImage(
String imagePath, String outputPath, String text) async {
final image = NetworkImage(imagePath);
final imageBytes = await image.resolve(ImageConfiguration()).toByteData();
final imageCodec = await instantiateImageCodec(imageBytes.buffer.asUint8List());
final frameInfo = await imageCodec.getNextFrame();
final imageWidget =
await flutterImage.instantiateImageCodec(frameInfo.image).then((value) => value.getNextFrame()).then((value) => value.image);
final recorder = ui.PictureRecorder();
final canvas = Canvas(recorder);
canvas.drawImage(imageWidget, Offset.zero, Paint());
final textStyle = ui.TextStyle(color: Colors.black, fontSize: 20);
final paragraphStyle = ui.ParagraphStyle(textAlign: TextAlign.center);
final paragraphBuilder =
ui.ParagraphBuilder(ui.ParagraphStyle(textAlign: TextAlign.center))
..pushStyle(textStyle)
..addText(text);
final paragraph = paragraphBuilder.build()
..layout(ui.ParagraphConstraints(width: imageWidget.width.toDouble()));
canvas.drawParagraph(
paragraph,
Offset((imageWidget.width - paragraph.width) / 2,
imageWidget.height.toDouble() - 50));
final picture = recorder.endRecording();
final imageWithText = await picture.toImage(
imageWidget.width.toInt(), imageWidget.height.toInt());
final pngBytes = await imageWithText.toByteData(format: ui.ImageByteFormat.png);
final output = File(outputPath);
await output.writeAsBytes(pngBytes.buffer.asUint8List());
}
}
ImageWithText
Widget:void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Add Text to Image',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: ImageWithText(),
);
}
}
这样,你就可以在Flutter中向图像添加文本。用户可以选择图像,输入文本并添加到图像上。最后,可以将带有文本的图像保存到设备上或进行其他操作。请注意,这只是一种实现方法,你可以根据自己的需求和偏好进行修改。
领取专属 10元无门槛券
手把手带您无忧上云