ImageUtils.java

/*
 * Copyright 2012 the original author or 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.
 */
package com.github.carlomicieli.nerdmovies.utility;

import org.springframework.http.MediaType;
import org.springframework.web.multipart.MultipartFile;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

import static org.imgscalr.Scalr.*;

/**
 * @author Carlo Micieli
 */
public class ImageUtils {
    public static byte[] createThumbnail(MultipartFile file, int targetSize) throws IOException {
        validateFile(file);

        final BufferedImage image = convertToImage(file);
        final BufferedImage thumb = pad(
                resize(image, Method.SPEED, targetSize, OP_ANTIALIAS, OP_BRIGHTER), 2);

        return convertToArray(thumb, file.getContentType());
    }

    public static byte[] convert(MultipartFile file) throws IOException {
        validateFile(file);
        return file.getBytes();
    }

    private static void validateFile(MultipartFile file) throws IOException {
        String contentType = file.getContentType();
        if (!contentType.equals(MediaType.IMAGE_JPEG.toString()) && !contentType.equals(MediaType.IMAGE_PNG.toString()))
            throw new IOException("Invalid media type");
    }

    private static BufferedImage convertToImage(MultipartFile file) throws IOException {
        InputStream in = new ByteArrayInputStream(file.getBytes());
        return ImageIO.read(in);
    }

    private static byte[] convertToArray(BufferedImage image, String contentType) throws IOException {
        byte[] imageInByte;

        String typeName = "jpg";
        if (contentType.equals(MediaType.IMAGE_PNG))
            typeName = "png";

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ImageIO.write(image, typeName, baos);
        baos.flush();
        imageInByte = baos.toByteArray();
        baos.close();

        return imageInByte;
    }
}