001/*
002 *  Copyright 2013 Anyware Services
003 *
004 *  Licensed under the Apache License, Version 2.0 (the "License");
005 *  you may not use this file except in compliance with the License.
006 *  You may obtain a copy of the License at
007 *
008 *      http://www.apache.org/licenses/LICENSE-2.0
009 *
010 *  Unless required by applicable law or agreed to in writing, software
011 *  distributed under the License is distributed on an "AS IS" BASIS,
012 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 *  See the License for the specific language governing permissions and
014 *  limitations under the License.
015 */
016package org.ametys.cms.transformation;
017
018import java.io.ByteArrayOutputStream;
019import java.io.IOException;
020import java.io.InputStream;
021
022import org.apache.commons.codec.binary.Base64;
023import org.apache.commons.io.IOUtils;
024import org.apache.commons.lang.StringUtils;
025
026import org.ametys.core.util.ImageHelper;
027
028/**
029 * Class providing helper methods to resolve images.
030 */
031public final class ImageResolverHelper
032{
033    
034    private ImageResolverHelper()
035    {
036        // Hides the default constructor.
037    }
038    
039    /**
040     * Get an image's bytes encoded as base64, optionally resized. 
041     * @param dataIs an input stream on the image bytes.
042     * @param mimeType the image mime type.
043     * @param height the specified height. Ignored if negative.
044     * @param width the specified width. Ignored if negative.
045     * @param maxHeight the maximum image height. Ignored if height or width is specified.
046     * @param maxWidth the maximum image width. Ignored if height or width is specified.
047     * @return the image bytes encoded as base64.
048     * @throws IOException if an error occurs.
049     */
050    public static final String resolveImageAsBase64(InputStream dataIs, String mimeType, int height, int width, int maxHeight, int maxWidth) throws IOException
051    {
052        if (!mimeType.startsWith("image/"))
053        {
054            return "";
055        }
056        
057        ByteArrayOutputStream buffer = new ByteArrayOutputStream();
058        
059        if (height == 0 && width == 0 && maxHeight == 0 && maxWidth == 0)
060        {
061            IOUtils.copy(dataIs, buffer);
062        }
063        else
064        {
065            String format = StringUtils.substringAfter(mimeType, "/");
066            ImageHelper.generateThumbnail(dataIs, buffer, format, height, width, maxHeight, maxWidth);
067        }
068        
069        String data = Base64.encodeBase64String(buffer.toByteArray());
070        
071        return "data:" + mimeType + ";base64," + data;
072    }
073    
074}