get Optimal Camera Preview Size - Android android.hardware

Android examples for android.hardware:Camera Preview

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Description

get Optimal Camera Preview Size

Demo Code

/*//  w w w.  j a  v  a 2  s.c  om
 * Copyright (C) 2009 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.
 */
import java.util.List;

import android.app.Activity;
import android.graphics.Point;
import android.hardware.Camera.Size;
import android.util.Log;

public class Main {

  private static final String TAG = "Util";

  public static Size getOptimalPreviewSize(Activity currentActivity, List<Size> sizes, double targetRatio) {

    Point[] points = new Point[sizes.size()];

    int index = 0;
    for (Size s : sizes) {
      points[index++] = new Point(s.width, s.height);
    }

    int optimalPickIndex = getOptimalPreviewSize(currentActivity, points, targetRatio);
    return (optimalPickIndex == -1) ? null : sizes.get(optimalPickIndex);
  }

  public static int getOptimalPreviewSize(Activity currentActivity, Point[] sizes, double targetRatio) {
    // Use a very small tolerance because we want an exact match.
    final double ASPECT_TOLERANCE = 0.01;
    if (sizes == null)
      return -1;

    int optimalSizeIndex = -1;
    double minDiff = Double.MAX_VALUE;

    // Because of bugs of overlay and layout, we sometimes will try to
    // layout the viewfinder in the portrait orientation and thus get the
    // wrong size of preview surface. When we change the preview size, the
    // new overlay will be created before the old one closed, which causes
    // an exception. For now, just get the screen size.
    Point point = getDefaultDisplaySize(currentActivity, new Point());
    int targetHeight = Math.min(point.x, point.y);
    // Try to find an size match aspect ratio and size
    for (int i = 0; i < sizes.length; i++) {
      Point size = sizes[i];
      double ratio = (double) size.x / size.y;
      if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)
        continue;
      if (Math.abs(size.y - targetHeight) < minDiff) {
        optimalSizeIndex = i;
        minDiff = Math.abs(size.y - targetHeight);
      }
    }
    // Cannot find the one match the aspect ratio. This should not happen.
    // Ignore the requirement.
    if (optimalSizeIndex == -1) {
      Log.w(TAG, "No preview size match the aspect ratio");
      minDiff = Double.MAX_VALUE;
      for (int i = 0; i < sizes.length; i++) {
        Point size = sizes[i];
        if (Math.abs(size.y - targetHeight) < minDiff) {
          optimalSizeIndex = i;
          minDiff = Math.abs(size.y - targetHeight);
        }
      }
    }
    return optimalSizeIndex;
  }

  private static Point getDefaultDisplaySize(Activity activity, Point size) {
    activity.getWindowManager().getDefaultDisplay().getSize(size);
    return size;
  }

}

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