setting opencv video to fullscreen android

问题

i am trying to set a video to fullscreen using opencv. the input is coming from the camera. it shows on the screen in the center but not as full screen. relevant code:

public class Sample3Native extends Activity implements CvCameraViewListener {
private static final String TAG = "OCVSample::Activity";

private Mat                    mRgba;
private Mat                    mGrayMat;
private Mat                    mFinalMat;

private CameraBridgeViewBase   mOpenCvCameraView;


private BaseLoaderCallback     mLoaderCallback = new BaseLoaderCallback(this) {
    @Override
    public void onManagerConnected(int status) {
        switch (status) {
            case LoaderCallbackInterface.SUCCESS:
            {
                Log.i(TAG, "OpenCV loaded successfully");

                // Load native library after(!) OpenCV initialization
                System.loadLibrary("native_sample");




                mOpenCvCameraView.enableView();



            } break;
            default:
            {
                super.onManagerConnected(status);
            } break;
        }
    }
};

public Sample3Native() {
    Log.i(TAG, "Instantiated new " + this.getClass());
}

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    Log.i(TAG, "called onCreate");
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

    setContentView(R.layout.tutorial3_surface_view);

    mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.tutorial4_activity_surface_view);
    mOpenCvCameraView.setCvCameraViewListener(this);


}

i have tried using:

//mOpenCvCameraView.setScaleX(0.8f);
                   // mOpenCvCameraView.setScaleY(0.4f);

                //mOpenCvCameraView.setMinimumHeight(800);
               // mOpenCvCameraView.setMinimumWidth(1000);

but it doesnot work.

how can i strech the frames to fill all of the screen?

回答1:

You can get a list of the available resolutions or setup manually.

If you want to get the list of the available sizes and get the optimal camera size.

   if (mOpenCvCameraView != null) {
        List<Size> sizes = mOpenCvCameraView.getSupportedPreviewSizes();
        int mFrameWidth = width;
        int mFrameHeight = height;

        // selecting optimal camera size
        {

            double minDiff = Double.MAX_VALUE;
            for (Size size : sizes) {
                if (Math.abs(size.height - height) < minDiff) {
                    mFrameWidth = (int) size.width;
                    mFrameHeight = (int) size.height;
                    minDiff = Math.abs(size.height - height);
                }
            }
        }

        mOpenCvCameraView.set(Highgui.CV_CAP_PROP_FRAME_WIDTH, mFrameWidth);
        mOpenCvCameraView.set(Highgui.CV_CAP_PROP_FRAME_HEIGHT, mFrameHeight);
    }

If the optimal camera size is not fullscreen, it is easy to get the great size that the camera support from the list.

Other option is to set manually the size:

        mOpenCvCameraView.set(Highgui.CV_CAP_PROP_FRAME_WIDTH, 1000);
        mOpenCvCameraView.set(Highgui.CV_CAP_PROP_FRAME_HEIGHT, 800);

The source of the code is from Face Detection OpenCV version 2.4.2.

回答2:

For those who google here and just want to change the resolution,

mOpenCvCameraView.set(Highgui.CV_CAP_PROP_FRAME_WIDTH, 1000) method is not working.

Try to use mOpenCvCameraView.setMaxFrameSize(640, 480);

It works for OCV4Android2.4.5, tutorial 2, mixed processing.

回答3:

For anyone still looking for this, I have solved the issue (sort-of). I cannot seem to get this to work for OpenCV v 2.4.3. I have tried everything on the internet. However, in OpenCV 2.4.3.2 they have added a way to set the camera size

disconnectCamera();
mMaxHeight = //your desired height
mMaxWidth = //your desired width
connectCamera(mMaxWidth, mMaxHeight);

Check out the OpenCV Tutorial 5, specifically the SampleJavaCameraView -> setResolution Method

回答4:

Not the best solution, but you can go to the AndroidManifest.xml and set android:screenOrientation="landscape"

With this you won't need to rotate de camera 90º, but your application will always be in landscape mode.

回答5:

Natural camera orientation of the OpenCV camera is landscape so make your activity is like

android:screenOrientation="landscape"

and apply this theme in the Activity

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <!-- Customize your theme here. -->
        ...
        <item name="android:windowFullscreen">true</item>
        <item name="android:windowContentOverlay">@null</item>
</style> 

this trick gives you a fullscreen camera.

回答6:

Try this replace

getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

code in the onCreate with

getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, 
                            WindowManager.LayoutParams.FLAG_FULLSCREEN);

来源：https://stackoverflow.com/questions/13376420/setting-opencv-video-to-fullscreen-android