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   The ASF licenses this file to You under the Apache License, Version 2.0
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package org.apache.batik.svggen;

import java.awt.Dimension;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.awt.image.RenderedImage;
import java.awt.image.renderable.RenderableImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.reflect.Method;

import org.w3c.dom.Element;

This class is a default implementation of the GenericImageHandler for handlers implementing a caching strategy.
Author:Vincent Hardy
See Also:
Version:$Id: DefaultCachedImageHandler.java 1805419 2017-08-18 13:04:30Z ssteiner $
/** * This class is a default implementation of the GenericImageHandler * for handlers implementing a caching strategy. * * @author <a href="mailto:vincent.hardy@eng.sun.com">Vincent Hardy</a> * @version $Id: DefaultCachedImageHandler.java 1805419 2017-08-18 13:04:30Z ssteiner $ * @see org.apache.batik.svggen.SVGGraphics2D */
public abstract class DefaultCachedImageHandler implements CachedImageHandler, SVGSyntax, ErrorConstants { // duplicate the string here to remove dependencies on // org.apache.batik.dom.util.XLinkSupport static final String XLINK_NAMESPACE_URI = "http://www.w3.org/1999/xlink"; static final AffineTransform IDENTITY = new AffineTransform(); // for createGraphics method. private static Method createGraphics = null; private static boolean initDone = false; private static final Class[] paramc = new Class[] {BufferedImage.class}; private static Object[] paramo = null; protected ImageCacher imageCacher;
The image cache can be used by subclasses for efficient image storage
/** * The image cache can be used by subclasses for efficient image storage */
public ImageCacher getImageCacher() { return imageCacher; } void setImageCacher(ImageCacher imageCacher) { if (imageCacher == null){ throw new IllegalArgumentException(); } // Save current DOMTreeManager if any DOMTreeManager dtm = null; if (this.imageCacher != null){ dtm = this.imageCacher.getDOMTreeManager(); } this.imageCacher = imageCacher; if (dtm != null){ this.imageCacher.setDOMTreeManager(dtm); } }
This GenericImageHandler implementation does not need to interact with the DOMTreeManager.
/** * This <code>GenericImageHandler</code> implementation does not * need to interact with the DOMTreeManager. */
public void setDOMTreeManager(DOMTreeManager domTreeManager){ imageCacher.setDOMTreeManager(domTreeManager); }
This method creates a Graphics2D from a BufferedImage. If Batik extensions to AWT are in the CLASSPATH it uses them, otherwise, it uses the regular AWT method.
/** * This method creates a <code>Graphics2D</code> from a * <code>BufferedImage</code>. If Batik extensions to AWT are * in the CLASSPATH it uses them, otherwise, it uses the regular * AWT method. */
private static Graphics2D createGraphics(BufferedImage buf) { if (!initDone) { try { Class clazz = Class.forName("org.apache.batik.ext.awt.image.GraphicsUtil"); createGraphics = clazz.getMethod("createGraphics", paramc); paramo = new Object[1]; } catch (Throwable t) { // happen only if Batik extensions are not their } finally { initDone = true; } } if (createGraphics == null) return buf.createGraphics(); else { paramo[0] = buf; Graphics2D g2d = null; try { g2d = (Graphics2D)createGraphics.invoke(null, paramo); } catch (Exception e) { // should not happened } return g2d; } }
Creates an Element which can refer to an image. Note that no assumptions should be made by the caller about the corresponding SVG tag. By default, an <image> tag is used, but the CachedImageHandlerBase64Encoder, for example, overrides this method to use a different tag.
/** * Creates an Element which can refer to an image. * Note that no assumptions should be made by the caller about the * corresponding SVG tag. By default, an &lt;image&gt; tag is * used, but the {@link CachedImageHandlerBase64Encoder}, for * example, overrides this method to use a different tag. */
public Element createElement(SVGGeneratorContext generatorContext) { // Create a DOM Element in SVG namespace to refer to an image Element imageElement = generatorContext.getDOMFactory().createElementNS (SVG_NAMESPACE_URI, SVG_IMAGE_TAG); return imageElement; }
The handler sets the xlink:href tag and returns a transform
/** * The handler sets the xlink:href tag and returns a transform */
public AffineTransform handleImage(Image image, Element imageElement, int x, int y, int width, int height, SVGGeneratorContext generatorContext) { int imageWidth = image.getWidth(null); int imageHeight = image.getHeight(null); AffineTransform af = null; if(imageWidth == 0 || imageHeight == 0 || width == 0 || height == 0) { // Forget about it handleEmptyImage(imageElement); } else { // First set the href try { handleHREF(image, imageElement, generatorContext); } catch (SVGGraphics2DIOException e) { try { generatorContext.errorHandler.handleError(e); } catch (SVGGraphics2DIOException io) { // we need a runtime exception because // java.awt.Graphics2D method doesn't throw exceptions.. throw new SVGGraphics2DRuntimeException(io); } } // Then create the transformation: // Because we cache image data, the stored image may // need to be scaled. af = handleTransform(imageElement, x, y, imageWidth, imageHeight, width, height, generatorContext); } return af; }
The handler sets the xlink:href tag and returns a transform
/** * The handler sets the xlink:href tag and returns a transform */
public AffineTransform handleImage(RenderedImage image, Element imageElement, int x, int y, int width, int height, SVGGeneratorContext generatorContext) { int imageWidth = image.getWidth(); int imageHeight = image.getHeight(); AffineTransform af = null; if(imageWidth == 0 || imageHeight == 0 || width == 0 || height == 0) { // Forget about it handleEmptyImage(imageElement); } else { // First set the href try { handleHREF(image, imageElement, generatorContext); } catch (SVGGraphics2DIOException e) { try { generatorContext.errorHandler.handleError(e); } catch (SVGGraphics2DIOException io) { // we need a runtime exception because // java.awt.Graphics2D method doesn't throw exceptions.. throw new SVGGraphics2DRuntimeException(io); } } // Then create the transformation: // Because we cache image data, the stored image may // need to be scaled. af = handleTransform(imageElement, x, y, imageWidth, imageHeight, width, height, generatorContext); } return af; }
The handler sets the xlink:href tag and returns a transform
/** * The handler sets the xlink:href tag and returns a transform */
public AffineTransform handleImage(RenderableImage image, Element imageElement, double x, double y, double width, double height, SVGGeneratorContext generatorContext) { double imageWidth = image.getWidth(); double imageHeight = image.getHeight(); AffineTransform af = null; if(imageWidth == 0 || imageHeight == 0 || width == 0 || height == 0) { // Forget about it handleEmptyImage(imageElement); } else { // First set the href try { handleHREF(image, imageElement, generatorContext); } catch (SVGGraphics2DIOException e) { try { generatorContext.errorHandler.handleError(e); } catch (SVGGraphics2DIOException io) { // we need a runtime exception because // java.awt.Graphics2D method doesn't throw exceptions.. throw new SVGGraphics2DRuntimeException(io); } } // Then create the transformation: // Because we cache image data, the stored image may // need to be scaled. af = handleTransform(imageElement, x,y, imageWidth, imageHeight, width, height, generatorContext); } return af; }
Determines the transformation needed to get the cached image to scale & position properly. Sets x and y attributes on the element accordingly.
/** * Determines the transformation needed to get the cached image to * scale &amp; position properly. Sets x and y attributes on the element * accordingly. */
protected AffineTransform handleTransform(Element imageElement, double x, double y, double srcWidth, double srcHeight, double dstWidth, double dstHeight, SVGGeneratorContext generatorContext) { // In this the default case, <image> element, we just // set x, y, width and height attributes. // No additional transform is necessary. imageElement.setAttributeNS(null, SVG_X_ATTRIBUTE, generatorContext.doubleString(x)); imageElement.setAttributeNS(null, SVG_Y_ATTRIBUTE, generatorContext.doubleString(y)); imageElement.setAttributeNS(null, SVG_WIDTH_ATTRIBUTE, generatorContext.doubleString(dstWidth)); imageElement.setAttributeNS(null, SVG_HEIGHT_ATTRIBUTE, generatorContext.doubleString(dstHeight)); return null; } protected void handleEmptyImage(Element imageElement) { imageElement.setAttributeNS(XLINK_NAMESPACE_URI, XLINK_HREF_QNAME, ""); imageElement.setAttributeNS(null, SVG_WIDTH_ATTRIBUTE, "0"); imageElement.setAttributeNS(null, SVG_HEIGHT_ATTRIBUTE, "0"); }
The handler should set the xlink:href tag and the width and height attributes.
/** * The handler should set the xlink:href tag and the width and * height attributes. */
public void handleHREF(Image image, Element imageElement, SVGGeneratorContext generatorContext) throws SVGGraphics2DIOException { if (image == null) throw new SVGGraphics2DRuntimeException(ERR_IMAGE_NULL); int width = image.getWidth(null); int height = image.getHeight(null); if (width==0 || height==0) { handleEmptyImage(imageElement); } else { if (image instanceof RenderedImage) { handleHREF((RenderedImage)image, imageElement, generatorContext); } else { BufferedImage buf = buildBufferedImage(new Dimension(width, height)); Graphics2D g = createGraphics(buf); g.drawImage(image, 0, 0, null); g.dispose(); handleHREF((RenderedImage)buf, imageElement, generatorContext); } } }
This method creates a BufferedImage of the right size and type for the derived class.
/** * This method creates a BufferedImage of the right size and type * for the derived class. */
public BufferedImage buildBufferedImage(Dimension size){ return new BufferedImage(size.width, size.height, getBufferedImageType()); }
This template method should set the xlink:href attribute on the input Element parameter
/** * This template method should set the xlink:href attribute on the input * Element parameter */
protected void handleHREF(RenderedImage image, Element imageElement, SVGGeneratorContext generatorContext) throws SVGGraphics2DIOException { // // Create an buffered image if necessary // BufferedImage buf = null; if (image instanceof BufferedImage && ((BufferedImage)image).getType() == getBufferedImageType()){ buf = (BufferedImage)image; } else { Dimension size = new Dimension(image.getWidth(), image.getHeight()); buf = buildBufferedImage(size); Graphics2D g = createGraphics(buf); g.drawRenderedImage(image, IDENTITY); g.dispose(); } // // Cache image and set xlink:href // cacheBufferedImage(imageElement, buf, generatorContext); }
This method will delegate to the handleHREF which uses a RenderedImage
/** * This method will delegate to the <code>handleHREF</code> which * uses a <code>RenderedImage</code> */
protected void handleHREF(RenderableImage image, Element imageElement, SVGGeneratorContext generatorContext) throws SVGGraphics2DIOException { // Create an buffered image where the image will be drawn Dimension size = new Dimension((int)Math.ceil(image.getWidth()), (int)Math.ceil(image.getHeight())); BufferedImage buf = buildBufferedImage(size); Graphics2D g = createGraphics(buf); g.drawRenderableImage(image, IDENTITY); g.dispose(); handleHREF((RenderedImage)buf, imageElement, generatorContext); } protected void cacheBufferedImage(Element imageElement, BufferedImage buf, SVGGeneratorContext generatorContext) throws SVGGraphics2DIOException { ByteArrayOutputStream os; if (generatorContext == null) throw new SVGGraphics2DRuntimeException(ERR_CONTEXT_NULL); try { os = new ByteArrayOutputStream(); // encode the image in memory encodeImage(buf, os); os.flush(); os.close(); } catch (IOException e) { // should not happen since we do in-memory processing throw new SVGGraphics2DIOException(ERR_UNEXPECTED, e); } // ask the cacher for a reference String ref = imageCacher.lookup(os, buf.getWidth(), buf.getHeight(), generatorContext); // set the URL imageElement.setAttributeNS(XLINK_NAMESPACE_URI, XLINK_HREF_QNAME, getRefPrefix() + ref); }
Should return the prefix with wich the image reference should be pre-concatenated.
/** * Should return the prefix with wich the image reference * should be pre-concatenated. */
public abstract String getRefPrefix();
Derived classes should implement this method and encode the input BufferedImage as needed
/** * Derived classes should implement this method and encode the input * BufferedImage as needed */
public abstract void encodeImage(BufferedImage buf, OutputStream os) throws IOException;
This template method should be overridden by derived classes to declare the image type they need for saving to file.
/** * This template method should be overridden by derived classes to * declare the image type they need for saving to file. */
public abstract int getBufferedImageType(); }