createCustomMarkerBitmap function

Future<BitmapDescriptor> createCustomMarkerBitmap(String title, { required TextStyle textStyle, bool visible = true, Color backgroundColor = Colors.blueAccent, })

Implementation

Future<BitmapDescriptor> createCustomMarkerBitmap(String title,
    {required TextStyle textStyle,
      bool visible = true,
    Color backgroundColor = Colors.blueAccent}) async {
  // title = "test dure label";
  TextSpan span = TextSpan(
    style: textStyle,
    text: title,
  );
  TextPainter painter = TextPainter(
    text: span,
    textAlign: TextAlign.center,
    textDirection: ui.TextDirection.ltr,
  );
  painter.text = TextSpan(
    text: title.toString(),
    style: textStyle,
  );
  ui.PictureRecorder pictureRecorder = ui.PictureRecorder();
  Canvas canvas = Canvas(pictureRecorder);
  painter.layout();
  painter.paint(canvas, const Offset(20.0, 10.0));
  int textWidth = painter.width.toInt();
  int textHeight = painter.height.toInt();
  canvas.drawRRect(
      RRect.fromLTRBAndCorners(0, 0, textWidth + 40, textHeight + 20,
          bottomLeft: const Radius.circular(10),
          bottomRight: const Radius.circular(10),
          topLeft: const Radius.circular(10),
          topRight: const Radius.circular(10)),
      Paint()..color = backgroundColor);
  var arrowPath = Path();
  arrowPath.moveTo((textWidth + 40) / 2 - 15, textHeight + 20);
  arrowPath.lineTo((textWidth + 40) / 2, textHeight + 40);
  arrowPath.lineTo((textWidth + 40) / 2 + 15, textHeight + 20);
  arrowPath.close();
  canvas.drawPath(arrowPath, Paint()..color = backgroundColor);
  painter.layout();
  painter.paint(canvas, const Offset(20.0, 10.0));
  // ui.Picture p = pictureRecorder.endRecording();
  // ByteData? pngBytes = await (await p.toImage(
  //         painter.width.toInt() + 40, painter.height.toInt() + 50))
  //     .toByteData(format: ui.ImageByteFormat.png);
  // Uint8List data = Uint8List.view(pngBytes!.buffer);


  // 绘制BitmapDescriptor.defaultMarker
  // BitmapDescriptor defaultMarker = BitmapDescriptor.defaultMarker;
  // Uint8List defaultMarkerData = await defaultMarker.toBytes();
  ByteData byteData = await rootBundle.load("images/location.png");
  Uint8List defaultMarkerData = await byteData.buffer.asUint8List();
  if (visible){
    // 将自定义图像和BitmapDescriptor.defaultMarker进行叠加
    int width = painter.width.toInt() + 40;
    int height = painter.height.toInt() + 50;
    ui.Picture p = pictureRecorder.endRecording();
    ByteData? pngBytes = await (await p.toImage(width, height)).toByteData(format: ui.ImageByteFormat.png);
    Uint8List customImageData = Uint8List.view(pngBytes!.buffer);

    // 创建一个新的Canvas并绘制自定义图像和BitmapDescriptor.defaultMarker
    final recorder = ui.PictureRecorder();
    final canvas2 = Canvas(recorder);
    final customImage = await decodeImageFromList(customImageData);
    final defaultMarkerImage = await decodeImageFromList(defaultMarkerData);
    canvas2.drawImage(customImage, Offset.zero, Paint());
    canvas2.drawImage(defaultMarkerImage, Offset(customImage.width.toDouble() / 2 - defaultMarkerImage.width.toDouble() / 2 , customImage.height.toDouble()), Paint());
    ui.Picture picture = recorder.endRecording();

    int mergeImageWidth = customImage.width;

    if (customImage.width < defaultMarkerImage.width){
      mergeImageWidth = defaultMarkerImage.width;
    }

    // 将叠加后的图像转换为BitmapDescriptor
    ByteData? mergedBytes = await (await picture.toImage(mergeImageWidth, customImage.height + defaultMarkerImage.height)).toByteData(format: ui.ImageByteFormat.png);
    Uint8List mergedData = mergedBytes!.buffer.asUint8List();
    return BitmapDescriptor.fromBytes(mergedData);
  }else{
    return BitmapDescriptor.fromBytes(defaultMarkerData);
  }


  // return BitmapDescriptor.fromBytes(data);
  // return BitmapDescriptor.defaultMarker;
}