Main.java Source code

Introduction

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.util.Log;

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

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

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

        // Find a suitable size, with max resolution
        int maxResolution = 0;
        Camera.Size maxResPreviewSize = null;
        for (Camera.Size size : rawSupportedSizes) {
            int realWidth = size.width;
            int realHeight = size.height;
            int resolution = realWidth * realHeight;
            if (resolution < MIN_PREVIEW_PIXELS) {
                continue;
            }

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

            // Resolution is suitable; record the one with max resolution
            if (resolution > maxResolution) {
                maxResolution = resolution;
                maxResPreviewSize = size;
            }
        }

        // 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 (maxResPreviewSize != null) {
            Point largestSize = new Point(maxResPreviewSize.width, maxResPreviewSize.height);
            Log.i(TAG, "Using largest suitable preview size: " + largestSize);
            return largestSize;
        }

        // If there is nothing at all suitable, return current preview size
        Camera.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;
    }
}