org.apache.xmlgraphics.image.loader.spi.ImagePreloader Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*/
/* $Id: ImagePreloader.java 750116 2009-03-04 19:23:59Z jeremias $ */
package org.apache.xmlgraphics.image.loader.spi;
import java.io.IOException;
import javax.xml.transform.Source;
import org.apache.xmlgraphics.image.loader.ImageContext;
import org.apache.xmlgraphics.image.loader.ImageException;
import org.apache.xmlgraphics.image.loader.ImageInfo;
/**
* This interface provides two functions: determining whether an image format is supported and if
* that's the case, some minimal information (mostly the image's intrinsic size) is extracted
* and returned.
*/
public interface ImagePreloader {
/** Default priority for preloaders */
int DEFAULT_PRIORITY = 1000;
/**
* "Preloads" an image, i.e. indentifies whether the source image is supported by this
* implementation and determines the image's intrinsic size and possibly some additional
* information. The image is usually not fully loaded at this time to conserve memory.
* The method returns null if the image was not identified. An {@link ImageException} is only
* thrown if the image is identified but some error has happened while working on the file.
* @param originalURI the original (unresolved) URI of the image
* @param src a image source the image is loaded from
* @param context the context object that provides configuration information
* @return an image info object with the basic information about an image or null if the
* image is not supported by this implementation
* @throws ImageException if an error occurs while preloading the image
* @throws IOException if an I/O error occurs while preloading the image
*/
ImageInfo preloadImage(String originalURI,
Source src, ImageContext context) throws ImageException, IOException;
/**
* Returns the priority of the preloader. The lower the value, the higher the preloader's
* priority.
* @return an integer (default is 1000)
*/
int getPriority();
}