CameraSourcePreview.java

/*
 * Copyright (C) The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.novoda.magicmirror.facerecognition;

import android.content.Context;
import android.content.res.Configuration;
import android.util.AttributeSet;

import com.novoda.notils.logger.simple.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.ViewGroup;

import com.google.android.gms.common.images.Size;
import com.google.android.gms.vision.CameraSource;

import java.io.IOException;

public class CameraSourcePreview extends ViewGroup {

    private static final int DEFAULT_PREVIEW_WIDTH = 320;
    private static final int DEFAULT_PREVIEW_HEIGHT = 240;

    private Context context;
    private boolean startRequested;
    private boolean surfaceAvailable;
    private CameraSource cameraSource;
    private final SurfaceView surfaceView;

    public CameraSourcePreview(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.context = context;
        startRequested = false;
        surfaceAvailable = false;

        surfaceView = new SurfaceView(context);
        surfaceView.getHolder().addCallback(new SurfaceCallback());
        addView(surfaceView);
    }

    public void start(CameraSource cameraSource) throws IOException {
        if (cameraSource == null) {
            stop();
            return;
        }

        this.cameraSource = cameraSource;

        startRequested = true;
        startIfReady();
    }

    public void stop() {
        if (cameraSource != null) {
            cameraSource.stop();
        }
    }

    private void startIfReady() throws IOException {
        if (startRequested && surfaceAvailable) {
            cameraSource.start(surfaceView.getHolder());
            startRequested = false;
        }
    }

    private class SurfaceCallback implements SurfaceHolder.Callback {
        @Override
        public void surfaceCreated(SurfaceHolder surface) {
            surfaceAvailable = true;
            try {
                startIfReady();
            } catch (IOException e) {
                Log.e("Could not start camera source.", e);
            }
        }

        @Override
        public void surfaceDestroyed(SurfaceHolder surface) {
            surfaceAvailable = false;
        }

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        }
    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        int width = DEFAULT_PREVIEW_WIDTH;
        int height = DEFAULT_PREVIEW_HEIGHT;
        if (cameraSource != null) {
            Size size = cameraSource.getPreviewSize();
            if (size != null) {
                width = size.getWidth();
                height = size.getHeight();
            }
        }

        // Swap width and height sizes when in portrait, since it will be rotated 90 degrees
        if (isPortraitMode()) {
            int tmp = width;
            width = height;
            height = tmp;
        }

        final int layoutWidth = right - left;
        final int layoutHeight = bottom - top;

        // Computes height and width for potentially doing fit width.
        int childWidth = layoutWidth;
        int childHeight = (int)(((float) layoutWidth / (float) width) * height);

        // If height is too tall using fit width, does fit height instead.
        if (childHeight > layoutHeight) {
            childHeight = layoutHeight;
            childWidth = (int)(((float) layoutHeight / (float) height) * width);
        }

        for (int i = 0; i < getChildCount(); ++i) {
            getChildAt(i).layout(0, 0, childWidth, childHeight);
        }

        try {
            startIfReady();
        } catch (IOException e) {
            Log.e("Could not start camera source.", e);
        }
    }

    private boolean isPortraitMode() {
        int orientation = context.getResources().getConfiguration().orientation;
        if (orientation == Configuration.ORIENTATION_LANDSCAPE) {
            return false;
        }
        if (orientation == Configuration.ORIENTATION_PORTRAIT) {
            return true;
        }

        Log.d("isPortraitMode returning false by default");
        return false;
    }
}