org.apache.xmlgraphics.image.loader.impl.imageio.ImageIOUtil 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: ImageIOUtil.java 1804124 2017-08-04 14:13:54Z ssteiner $ */
package org.apache.xmlgraphics.image.loader.impl.imageio;
import javax.imageio.metadata.IIOMetadata;
import javax.imageio.metadata.IIOMetadataFormatImpl;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.apache.xmlgraphics.image.loader.ImageSize;
import org.apache.xmlgraphics.util.UnitConv;
/**
* Helper and convenience methods for ImageIO.
*/
public final class ImageIOUtil {
private ImageIOUtil() {
}
/** Key for ImageInfo's custom objects to embed the ImageIO metadata */
public static final Object IMAGEIO_METADATA = IIOMetadata.class;
/**
* Extracts the resolution information from the standard ImageIO metadata.
* @param iiometa the metadata provided by ImageIO
* @param size the image size object
*/
public static void extractResolution(IIOMetadata iiometa, ImageSize size) {
if (iiometa != null && iiometa.isStandardMetadataFormatSupported()) {
Element metanode = (Element)iiometa.getAsTree(
IIOMetadataFormatImpl.standardMetadataFormatName);
Element dim = getChild(metanode, "Dimension");
if (dim != null) {
Element child;
double dpiHorz = size.getDpiHorizontal();
double dpiVert = size.getDpiVertical();
child = getChild(dim, "HorizontalPixelSize");
if (child != null) {
float value = Float.parseFloat(child.getAttribute("value"));
if (value != 0 && !Float.isInfinite(value)) {
dpiHorz = UnitConv.IN2MM / value;
}
}
child = getChild(dim, "VerticalPixelSize");
if (child != null) {
float value = Float.parseFloat(child.getAttribute("value"));
if (value != 0 && !Float.isInfinite(value)) {
dpiVert = UnitConv.IN2MM / value;
}
}
size.setResolution(dpiHorz, dpiVert);
size.calcSizeFromPixels();
}
}
}
/**
* Returns a child element of another element or null if there's no such child.
* @param el the parent element
* @param name the name of the requested child
* @return the child or null if there's no such child
*/
public static Element getChild(Element el, String name) {
NodeList nodes = el.getElementsByTagName(name);
if (nodes.getLength() > 0) {
return (Element)nodes.item(0);
} else {
return null;
}
}
/**
* Dumps the content of an IIOMetadata instance to System.out.
* @param iiometa the metadata
*/
public static void dumpMetadataToSystemOut(IIOMetadata iiometa) {
String[] metanames = iiometa.getMetadataFormatNames();
for (String metaname : metanames) {
System.out.println("--->" + metaname);
dumpNodeToSystemOut(iiometa.getAsTree(metaname));
}
}
/**
* Serializes a W3C DOM node to a String and dumps it to System.out.
* @param node a W3C DOM node
*/
private static void dumpNodeToSystemOut(Node node) {
Transformer trans = null;
try {
trans = TransformerFactory.newInstance().newTransformer();
trans.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
trans.setOutputProperty(OutputKeys.INDENT, "yes");
Source src = new DOMSource(node);
Result res = new StreamResult(System.out);
trans.transform(src, res);
} catch (TransformerConfigurationException e) {
e.printStackTrace();
} catch (TransformerException e) {
e.printStackTrace();
}
}
}