Main.java Source code

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Here is the source code for Main.java

Source

//package com.java2s;
/*
 * Copyright (C) 2014 ZXing authors
 *
 * 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 android.graphics.Point;

import android.hardware.Camera;
import android.hardware.Camera.Size;

import android.util.Log;
import java.util.ArrayList;

import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;

public class Main {
    private static final String TAG = "CameraConfiguration";
    private static final int MIN_PREVIEW_PIXELS = 480 * 320;
    private static final double MAX_ASPECT_DISTORTION = 0.15;

    public static Point findBestPreviewSizeValue(Camera.Parameters parameters, Point screenResolution) {

        List<Size> rawSupportedSizes = parameters.getSupportedPreviewSizes();
        if (rawSupportedSizes == null) {
            Log.w(TAG, "Device returned no supported preview sizes; using default");
            Size defaultSize = parameters.getPreviewSize();
            if (defaultSize == null) {
                throw new IllegalStateException("Parameters contained no preview size!");
            }
            return new Point(defaultSize.width, defaultSize.height);
        }

        // Sort by size, descending
        List<Size> supportedPreviewSizes = new ArrayList<Size>(rawSupportedSizes);
        Collections.sort(supportedPreviewSizes, new Comparator<Size>() {
            @Override
            public int compare(Size a, Size b) {
                int aPixels = a.height * a.width;
                int bPixels = b.height * b.width;
                if (bPixels < aPixels) {
                    return -1;
                }
                if (bPixels > aPixels) {
                    return 1;
                }
                return 0;
            }
        });

        if (Log.isLoggable(TAG, Log.INFO)) {
            StringBuilder previewSizesString = new StringBuilder();
            for (Size supportedPreviewSize : supportedPreviewSizes) {
                previewSizesString.append(supportedPreviewSize.width).append('x')
                        .append(supportedPreviewSize.height).append(' ');
            }
            Log.i(TAG, "Supported preview sizes: " + previewSizesString);
        }

        double screenAspectRatio = (double) screenResolution.x / (double) screenResolution.y;

        // Remove sizes that are unsuitable
        Iterator<Size> it = supportedPreviewSizes.iterator();
        while (it.hasNext()) {
            Size supportedPreviewSize = it.next();
            int realWidth = supportedPreviewSize.width;
            int realHeight = supportedPreviewSize.height;
            if (realWidth * realHeight < MIN_PREVIEW_PIXELS) {
                it.remove();
                continue;
            }

            boolean isCandidatePortrait = realWidth < realHeight;
            int maybeFlippedWidth = isCandidatePortrait ? realHeight : realWidth;
            int maybeFlippedHeight = isCandidatePortrait ? realWidth : realHeight;
            double aspectRatio = (double) maybeFlippedWidth / (double) maybeFlippedHeight;
            double distortion = Math.abs(aspectRatio - screenAspectRatio);
            if (distortion > MAX_ASPECT_DISTORTION) {
                it.remove();
                continue;
            }

            if (maybeFlippedWidth == screenResolution.x && maybeFlippedHeight == screenResolution.y) {
                Point exactPoint = new Point(realWidth, realHeight);
                Log.i(TAG, "Found preview size exactly matching screen size: " + exactPoint);
                return exactPoint;
            }
        }

        // If no exact match, use largest preview size. This was not a great idea on older devices because
        // of the additional computation needed. We're likely to get here on newer Android 4+ devices, where
        // the CPU is much more powerful.
        if (!supportedPreviewSizes.isEmpty()) {
            Size largestPreview = supportedPreviewSizes.get(0);
            Point largestSize = new Point(largestPreview.width, largestPreview.height);
            Log.i(TAG, "Using largest suitable preview size: " + largestSize);
            return largestSize;
        }

        // If there is nothing at all suitable, return current preview size
        Size defaultPreview = parameters.getPreviewSize();
        if (defaultPreview == null) {
            throw new IllegalStateException("Parameters contained no preview size!");
        }
        Point defaultSize = new Point(defaultPreview.width, defaultPreview.height);
        Log.i(TAG, "No suitable preview sizes, using default: " + defaultSize);
        return defaultSize;
    }
}