get Optimal Preview Size by targetRatio - Android Camera

Android examples for Camera:Camera Preview

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  4. Camera Preview

Description

get Optimal Preview Size by targetRatio

Demo Code


//package com.java2s;
import android.content.Context;

import android.graphics.Point;
import android.hardware.Camera;
import android.util.Log;
import android.view.Display;

import android.view.WindowManager;
import java.util.List;

public class Main {
    private static final String TAG = "CameraHelper";

    public static Camera.Size getOptimalPreviewSize(Context context,
            List<Camera.Size> sizes, double targetRatio) {
        // Use a very small tolerance because we want an exact match.
        final double ASPECT_TOLERANCE = 0.001;
        if (sizes == null)
            return null;

        Camera.Size optimalSize = null;// www .j a  v a 2s . co  m
        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.
        WindowManager windowManager = (WindowManager) context
                .getSystemService(Context.WINDOW_SERVICE);

        Display defaultDisplay = windowManager.getDefaultDisplay();

        Point point = new Point();
        defaultDisplay.getSize(point);

        int targetHeight = Math.min(point.x, point.y);
        // Try to find an size match aspect ratio and size
        for (Camera.Size size : sizes) {
            double ratio = (double) size.width / size.height;
            if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)
                continue;
            if (Math.abs(size.height - targetHeight) < minDiff) {
                optimalSize = size;
                minDiff = Math.abs(size.height - targetHeight);
            }
        }
        // Cannot find the one match the aspect ratio. This should not happen.
        // Ignore the requirement.
        if (optimalSize == null) {
            Log.w(TAG, "No preview size match the aspect ratio");
            minDiff = Double.MAX_VALUE;
            for (Camera.Size size : sizes) {
                if (Math.abs(size.height - targetHeight) < minDiff) {
                    optimalSize = size;
                    minDiff = Math.abs(size.height - targetHeight);
                }
            }
        }
        return optimalSize;
    }
}

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