OpenCvUtils.java

package marshal.opencvproto;

import org.opencv.core.Mat;

import android.util.Log;

import com.google.gson.Gson;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

public class OpenCvUtils {
	public static String matToJson(Mat mat) {
		JsonObject obj = new JsonObject();

		if (mat.isContinuous()) {
			StringBuilder builder = new StringBuilder();

			for (int i = 0; i < mat.rows(); i++) {
				double[] d = mat.get(i, 0);
				builder.append(d[0]);
				if (i != mat.rows() - 1) {
					builder.append(",");
				}
			}

			obj.addProperty("rows", mat.rows());
			obj.addProperty("cols", mat.cols());
			obj.addProperty("type", mat.type());
			obj.addProperty("data", builder.toString());

			Gson gson = new Gson();
			String json = gson.toJson(obj);

			Log.d("opencv_detector", "json: " + json);
			return json;
		} else {
			Log.e("opencv_detector", "Mat not continuous.");
		}
		return "{}";
	}

	public static Mat matFromJson(String json) {
		JsonParser parser = new JsonParser();
		JsonObject JsonObject = parser.parse(json).getAsJsonObject();

		int rows = JsonObject.get("rows").getAsInt();
		int cols = JsonObject.get("cols").getAsInt();
		int type = JsonObject.get("type").getAsInt();

		String dataString = JsonObject.get("data").getAsString();

		Mat mat = new Mat(rows, cols, type);

		int rowIndex = 0;

		for (String s : dataString.split(",")) {
			mat.put(rowIndex++, 0, Double.parseDouble(s));
		}

		return mat;

	}
}