ColorBlobDetectionView.java

package org.opencv.samples.colorblobdetect;

import java.util.List;
import org.opencv.android.Utils;
import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.core.MatOfPoint;
import org.opencv.core.Rect;
import org.opencv.core.Scalar;
import org.opencv.core.Size;
import org.opencv.highgui.Highgui;
import org.opencv.highgui.VideoCapture;
import org.opencv.imgproc.Imgproc;

import android.content.Context;
import android.graphics.Bitmap;
import android.util.Log;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.View;
import android.view.View.OnTouchListener;

public class ColorBlobDetectionView extends SampleCvViewBase implements OnTouchListener {
    private static final String TAG                 = "OCVSample::View";

    private Mat                 mRgba;
    private boolean             mIsColorSelected    = false;
    private Scalar              mBlobColorRgba      = new Scalar(255);
    private Scalar              mBlobColorHsv       = new Scalar(255);
    private ColorBlobDetector   mDetector           = new ColorBlobDetector();
    private Mat                 mSpectrum           = new Mat();
    private static Size         SPECTRUM_SIZE       = new Size(200, 32);
    private static final Scalar CONTOUR_COLOR       = new Scalar(255,0,0,255);


    public ColorBlobDetectionView(Context context) {
        super(context);
        setOnTouchListener(this);
        Log.i(TAG, "Instantiated new " + this.getClass());
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        Log.i(TAG, "called surfaceCreated");
        synchronized (this) {
            // initialize Mat before usage
            mRgba = new Mat();
        }

        super.surfaceCreated(holder);
    }

    private Scalar converScalarHsv2Rgba(Scalar hsvColor) {
        Mat pointMatRgba = new Mat();
        Mat pointMatHsv = new Mat(1, 1, CvType.CV_8UC3, hsvColor);
        Imgproc.cvtColor(pointMatHsv, pointMatRgba, Imgproc.COLOR_HSV2RGB_FULL, 4);

        return new Scalar(pointMatRgba.get(0, 0));
    }

    public boolean onTouch(View v, MotionEvent event) {
        int cols = mRgba.cols();
        int rows = mRgba.rows();

        int xOffset = (getWidth() - cols) / 2;
        int yOffset = (getHeight() - rows) / 2;

        int x = (int)event.getX() - xOffset;
        int y = (int)event.getY() - yOffset;

        Log.i(TAG, "Touch image coordinates: (" + x + ", " + y + ")");

        if ((x < 0) || (y < 0) || (x > cols) || (y > rows)) return false;

        Rect touchedRect = new Rect();

        touchedRect.x = (x>4) ? x-4 : 0;
        touchedRect.y = (y>4) ? y-4 : 0;

        touchedRect.width = (x+4 < cols) ? x + 4 - touchedRect.x : cols - touchedRect.x;
        touchedRect.height = (y+4 < rows) ? y + 4 - touchedRect.y : rows - touchedRect.y;

        Mat touchedRegionRgba = mRgba.submat(touchedRect);

        Mat touchedRegionHsv = new Mat();
        Imgproc.cvtColor(touchedRegionRgba, touchedRegionHsv, Imgproc.COLOR_RGB2HSV_FULL);

        // Calculate average color of touched region
        mBlobColorHsv = Core.sumElems(touchedRegionHsv);
        int pointCount = touchedRect.width*touchedRect.height;
        for (int i = 0; i < mBlobColorHsv.val.length; i++)
            mBlobColorHsv.val[i] /= pointCount;

        mBlobColorRgba = converScalarHsv2Rgba(mBlobColorHsv);

        Log.i(TAG, "Touched rgba color: (" + mBlobColorRgba.val[0] + ", " + mBlobColorRgba.val[1] +
                ", " + mBlobColorRgba.val[2] + ", " + mBlobColorRgba.val[3] + ")");

        mDetector.setHsvColor(mBlobColorHsv);

        Imgproc.resize(mDetector.getSpectrum(), mSpectrum, SPECTRUM_SIZE);

        mIsColorSelected = true;

        return false; // don't need subsequent touch events
    }

    @Override
    protected Bitmap processFrame(VideoCapture capture) {
        capture.retrieve(mRgba, Highgui.CV_CAP_ANDROID_COLOR_FRAME_RGBA);

        Bitmap bmp = Bitmap.createBitmap(mRgba.cols(), mRgba.rows(), Bitmap.Config.ARGB_8888);

        if (mIsColorSelected) {
            mDetector.process(mRgba);
            List<MatOfPoint> contours = mDetector.getContours();
            Log.e(TAG, "Contours count: " + contours.size());
            Core.drawContours(mRgba, contours, -1, CONTOUR_COLOR);

            Mat colorLabel = mRgba.submat(2, 34, 2, 34);
            colorLabel.setTo(mBlobColorRgba);

            Mat spectrumLabel = mRgba.submat(2, 2 + mSpectrum.rows(), 38, 38 + mSpectrum.cols());
            mSpectrum.copyTo(spectrumLabel);
        }

        try {
            Utils.matToBitmap(mRgba, bmp);
        } catch(Exception e) {
            Log.e(TAG, "Utils.matToBitmap() throws an exception: " + e.getMessage());
            bmp.recycle();
            bmp = null;
        }

        return bmp;
    }

    @Override
    public void run() {
        super.run();

        synchronized (this) {
            // Explicitly deallocate Mats
            if (mRgba != null)
                mRgba.release();

            mRgba = null;
        }
    }
}