Android Open Source - qrcode-android Froyo Exposure Interface

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License

The source code is released under:

MIT License

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Java Source Code

/*
 * Copyright (C) 2012 ZXing authors/* w ww  .  j av a2 s  .  c  o m*/
 *
 * 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.google.zxing.client.android.camera.exposure;

import android.annotation.TargetApi;
import android.hardware.Camera;
import android.util.Log;

@TargetApi(8)
public final class FroyoExposureInterface implements ExposureInterface
{

    private static final String TAG = FroyoExposureInterface.class.getSimpleName();

    private static final float MAX_EXPOSURE_COMPENSATION = 1.5f;
    private static final float MIN_EXPOSURE_COMPENSATION = 0.0f;

    @Override
    public void setExposure(Camera.Parameters parameters, boolean lightOn)
    {
        int minExposure = parameters.getMinExposureCompensation();
        int maxExposure = parameters.getMaxExposureCompensation();
        if (minExposure != 0 || maxExposure != 0)
        {
            float step = parameters.getExposureCompensationStep();
            int desiredCompensation;
            if (lightOn)
            {
                // Light on; set low exposue compensation
                desiredCompensation = Math.max((int) (MIN_EXPOSURE_COMPENSATION / step), minExposure);
            } else
            {
                // Light off; set high compensation
                desiredCompensation = Math.min((int) (MAX_EXPOSURE_COMPENSATION / step), maxExposure);
            }
            Log.i(TAG, "Setting exposure compensation to " + desiredCompensation + " / " + (step * desiredCompensation));
            parameters.setExposureCompensation(desiredCompensation);
        } else
        {
            Log.i(TAG, "Camera does not support exposure compensation");
        }
    }

}

Java Source Code List