如何在flutter中以编程方式删除图像背景

Question

当我从图像选取器中选取图像时，我需要将图像背景移除为白色，但我不想使用API来完成这项工作。我可以使用第三方插件。

Answer 1

如果您想要自定义背景颜色，您需要更改行

Img.Image transparentImage = await colorTransparent(image, 255, 255, 255);

现在是255255255，所以现在是白色。

Future<Uint8List> _downloadImage() async {
String dir = (await getApplicationDocumentsDirectory()).path;
File file = new File('$dir/$_filename');
if (file.existsSync()) {
var image = await file.readAsBytes();
return image;
} else {
var response = await http.get(_url,);
var bytes = response.bodyBytes;
Uint8List newPng = await removeWhiteBackground(bytes);
file.writeAsBytes(newPng);
return newPng;
}
}
Future<Uint8List> removeWhiteBackground(Uint8List bytes) async {
Img.Image image = Img.decodeImage(bytes);
Img.Image transparentImage = await colorTransparent(image, 255, 255, 255);
var newPng = Img.encodePng(transparentImage);
return newPng;
}
Future<Img.Image> colorTransparent(Img.Image src, int red, int green, int blue) async {
var pixels = src.getBytes();
for (int i = 0, len = pixels.length; i < len; i += 4) {
if(pixels[i] == red
&& pixels[i+1] == green
&& pixels[i+2] == blue
) {
pixels[i + 3] = 0;
}
}
return src;
}