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• Java2DRenderer.java

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org.xhtmlrenderer.swing.Java2DRenderer Maven / Gradle / Ivy

/*
 * {{{ header & license
 * Copyright (c) 2006 Wisconsin Court System and  Patrick Wright
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 * }}}
 */
package org.xhtmlrenderer.swing;

import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Map;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.xhtmlrenderer.extend.NamespaceHandler;
import org.xhtmlrenderer.extend.UserAgentCallback;
import org.xhtmlrenderer.extend.UserInterface;
import org.xhtmlrenderer.layout.BoxBuilder;
import org.xhtmlrenderer.layout.LayoutContext;
import org.xhtmlrenderer.layout.SharedContext;
import org.xhtmlrenderer.render.BlockBox;
import org.xhtmlrenderer.render.Box;
import org.xhtmlrenderer.render.RenderingContext;
import org.xhtmlrenderer.render.ViewportBox;
import org.xhtmlrenderer.simple.extend.XhtmlNamespaceHandler;
import org.xhtmlrenderer.util.Configuration;
import org.xhtmlrenderer.util.ImageUtil;

/**
 * 
Renders an XML files, formatted with CSS, as an image. Input is a document in the form of file or URL,
 * and output is a BufferedImage. A Java2DRenderer is not intended to be re-used for multiple document
 * sources; just create new Java2DRenderers for each one you need. Java2DRenderer is not thread-safe.
 * Standard usage pattern is
 *
 * 
 * File xhtml = ...
 * Java2DRenderer rend = new Java2DRenderer(xhtml);
 * BufferedImage image = rend.getImage();
 * 
 *
 * 
The document is not loaded, and layout and render don't take place, until {@link #getImage(int)}  is called.
 * Subsequent calls to {@link #getImage()} don't result in a reload; create a new Java2DRenderer instance to do so.
 *
 * 
As with {@link org.xhtmlrenderer.swing.RootPanel}, you can access the
 * {@link org.xhtmlrenderer.layout.SharedContext} instance that will be used by this renderer and change settings
 * to control the rendering process; use {@link #getSharedContext()}.
 *
 * 
By default, this renderer will render to an RGB image which does not support transparency. To use another type
 * of BufferedImage, either set the image type using {@link #setBufferedImageType(int)} before calling
 * {@link #getImage()}, or else override the {@link #createBufferedImage(int, int)} to have full control over
 * the image we render to.
 *
 * 
Not thread-safe.
 *
 * @see ITextRenderer
 */
public class Java2DRenderer {
	private static final int DEFAULT_HEIGHT = 1000;
	private static final int DEFAULT_DOTS_PER_POINT = 1;
	private static final int DEFAULT_DOTS_PER_PIXEL = 1;
	private static final int DEFAULT_IMAGE_TYPE = BufferedImage.TYPE_INT_RGB;

	private SharedContext sharedContext;
	private Java2DOutputDevice outputDevice;

	private Document doc;
	private Box root;

	private float dotsPerPoint;
	private BufferedImage outputImage;
	private int bufferedImageType;


	/**
	 * Whether we've completed rendering; image will only be rendered once.
	 */
	private boolean rendered;
	private String sourceDocument;
	private String sourceDocumentBase;
	private int width;
	private int height;
	private static final int NO_HEIGHT = -1;
	private Map renderingHints;


	/**
	 * Base constructor
	 */
	private Java2DRenderer() {
		this.bufferedImageType = DEFAULT_IMAGE_TYPE;
	}

	/**
	 * Creates a new instance with specific scaling paramters; these are currently ignored.
	 *
	 * @param dotsPerPoint Layout XML at so many dots per point
	 * @param dotsPerPixel Layout XML at so many dots per pixel
	 */
	private Java2DRenderer(float dotsPerPoint, int dotsPerPixel) {
		this();
		init(dotsPerPoint, dotsPerPixel);
	}

	/**
	 * Creates a new instance for a given URL. Does not render until {@link #getImage(int)} is called for
	 * the first time.
	 *
	 * @param url The location of the document to be rendered.
	 * @param baseurl The base url for the document, against which  relative paths are resolved.
	 * @param width Target width, in pixels, for the image; required to provide horizontal bounds for the layout.
	 */
	public Java2DRenderer(String url, String baseUrl, int width, int height) {
		// bypass scaling routines based on DPI -- see PDFRenderer and compare--dotsPerPoint is not implemented
		// in all subordinate classes and interfaces for Java2D, so leaving it out
		// leaving this constructor call here as a TODO
		this(DEFAULT_DOTS_PER_POINT, DEFAULT_DOTS_PER_PIXEL);

		this.sourceDocument = url;
		this.sourceDocumentBase = baseUrl;
		this.width = width;
		this.height = height;
	}

	/**
	 * Creates a new instance for a given File. Does not render until {@link #getImage(int)} is called for
	 * the first time.
	 *
	 * @param file The file to be rendered.
	 * @param width Target width, in pixels, for the image; required to provide horizontal bounds for the layout.
	 * @param height Target height, in pixels, for the image
	 */
	public Java2DRenderer(File file, int width, int height) throws IOException {
		this(file.toURI().toURL().toExternalForm(), width, height);
	}
   
   
        /**
         * Creates a new instance pointing to the given Document. Does not render until {@link #getImage(int)} is called for
         * the first time.
         *
         * @param doc The document to be rendered.
         * @param width Target width, in pixels, for the image; required to provide horizontal bounds for the layout.
         * @param height Target height, in pixels, for the image.
         */
        public Java2DRenderer(Document doc, int width, int height) {
            this(DEFAULT_DOTS_PER_POINT, DEFAULT_DOTS_PER_PIXEL);
            this.doc = doc;
            this.width = width;
            this.height = height;
        }

	public Java2DRenderer(Document doc, int width) {
		this(doc, width, NO_HEIGHT);
	}

        /**
         * Creates a new instance pointing to the given Document. Does not render until {@link #getImage(int)} is called for
         * the first time.
         *
         * @param doc The document to be rendered.
         * @param baseUrl The base url for the document, against which  relative paths are resolved.
         * @param width Target width, in pixels, for the image; required to provide horizontal bounds for the layout.
         * @param height Target height, in pixels, for the image.
         */
        public Java2DRenderer(Document doc, String baseUrl, int width, int height) {
            this(doc, width, height);
            this.sourceDocumentBase = baseUrl;
        }

	/**
	 * Creates a new instance for a given File. Does not render until {@link #getImage(int)} is called for
	 * the first time.
	 *
	 * @param file The file to be rendered.
	 * @param width Target width, in pixels, for the image; required to provide horizontal bounds for the layout.
	 * Heght is calculated based on content
	 */
	public Java2DRenderer(File file, int width) throws IOException {
		this(file.toURI().toURL().toExternalForm(), width);
	}


	/**
	 * Renderer for a given URL (which is also used as the base) and a specified width; height is calculated
	 * automatically.
	 *
	 * @param url The location of the document to be rendered.
	 * @param width Target width, in pixels, for the image; required to provide horizontal bounds for the layout.
	 * Heght is calculated based on content
	 */
	public Java2DRenderer(String url, int width) {
		this(url, url, width, NO_HEIGHT);
	}

	/**
	 * Renderer for a given URL and a specified width; height is calculated
	 * automatically.
	 *
	 * @param url The location of the document to be rendered.
	 * @param baseurl The base url for the document, against which  relative paths are resolved.
	 * @param width Target width, in pixels, for the image; required to provide horizontal bounds for the layout.
	 * Heght is calculated based on content
	 */
	public Java2DRenderer(String url, String baseurl, int width) {
		this(url, baseurl, width, NO_HEIGHT);
	}

	/**
	 * Renderer for a given URL and a specified width; height is calculated
	 * automatically.
	 *
	 * @param url The location of the document to be rendered.
	 * @param baseurl The base url for the document, against which  relative paths are resolved.
	 * @param width Target width, in pixels, for the image; required to provide horizontal bounds for the layout.
	 * @param height Target height, in pixels, for the image
	 */
	public Java2DRenderer(String url, int width, int height) {
		this(url, url, width, height);
	}

	/**
	 * Sets the rendering hints to apply to the Graphics2D instance used by the renderer; see
	 * {@link java.awt.Graphics2D#setRenderingHints(java.util.Map)}. The Map need not specify values for all
	 * properties; any settings in this map will be applied as override to the default settings, and will
	 * not replace the entire Map for the Graphics2D instance.
	 *
	 * @param hints values to override in default rendering hints for Graphics2D we are rendering to
	 */
	public void setRenderingHints(Map hints) {
		renderingHints = hints;
	}

	/**
	 * Sets the type for the BufferedImage used as output for this renderer; must be one of the values from
	 * {@link java.awt.image.BufferedImage} allowed in that class' constructor as a type argument. See docs for
	 * the type parameter in {@link java.awt.image.BufferedImage#BufferedImage(int, int, int)}. Defaults to RGB with
	 * no support for transparency. The type is used when the image is first created, so to change the default type
	 * do so before calling {@link #getImage()}.
	 *
	 * @param bufferedImageType the BufferedImage type to be used to create the image on which the document
	 * will be rendered.
	 */
	public void setBufferedImageType(int bufferedImageType) {
		this.bufferedImageType = bufferedImageType;
	}

	/**
	 * Returns the SharedContext to be used by renderer. Is instantiated along with the class, so can be accessed
	 * before {@link #getImage()} is called to tune the rendering process.
	 *
	 * @return the SharedContext instance that will be used by this renderer
	 */
	public SharedContext getSharedContext() {
		return sharedContext;
	}

	/**
	 * Renders the XML document if necessary and returns the resulting image. If already rendered, same image
	 * reference will be returned.
	 *
	 * {@link #getImage(int)} with the target width.
	 * 
	 * @return The XML rendered as a BufferedImage.
	 */
	public BufferedImage getImage() {
		if (!rendered) {
            setDocument((doc == null ? loadDocument(sourceDocument) : doc), sourceDocumentBase, new XhtmlNamespaceHandler());

			layout(this.width);

			height = this.height == -1 ? root.getHeight() : this.height;
			outputImage = createBufferedImage(this.width, height);
			outputDevice = new Java2DOutputDevice(outputImage);
			Graphics2D newG = (Graphics2D) outputImage.getGraphics();
			if ( renderingHints != null ) {
				newG.addRenderingHints(renderingHints);
			}

			RenderingContext rc = sharedContext.newRenderingContextInstance();
			rc.setFontContext(new Java2DFontContext(newG));
			rc.setOutputDevice(outputDevice);
			sharedContext.getTextRenderer().setup(rc.getFontContext());

			root.getLayer().paint(rc);

			newG.dispose();
			rendered = true;
		}

		return outputImage;
	}

	/**
	 * Returns a BufferedImage using the specified width and height. By default this returns an image compatible
	 * with the screen (if not in "headless" mode) using the BufferedImage type specified in
	 * {@link #setBufferedImageType(int)}, or else RGB if none if specified.
	 *
	 * @param width target width
	 * @param height target height
	 * @return new BI
	 */
	protected BufferedImage createBufferedImage(int width, int height) {
		BufferedImage image = ImageUtil.createCompatibleBufferedImage(width, height, this.bufferedImageType);
		ImageUtil.clearImage(image);
		return image;
	}

	private void setDocument(Document doc, String url, NamespaceHandler nsh) {
		this.doc = doc;

		sharedContext.reset();
		if (Configuration.isTrue("xr.cache.stylesheets", true)) {
			sharedContext.getCss().flushStyleSheets();
		} else {
			sharedContext.getCss().flushAllStyleSheets();
		}
		sharedContext.setBaseURL(url);
		sharedContext.setNamespaceHandler(nsh);
		sharedContext.getCss().setDocumentContext(
				sharedContext,
				sharedContext.getNamespaceHandler(),
				doc,
				new NullUserInterface()
		);
	}

	private void layout(int width) {
		Rectangle rect = new Rectangle(0, 0, width, DEFAULT_HEIGHT);
		sharedContext.set_TempCanvas(rect);
		LayoutContext c = newLayoutContext();
		BlockBox root = BoxBuilder.createRootBox(c, doc);
		root.setContainingBlock(new ViewportBox(rect));
		root.layout(c);
		this.root = root;
	}

	private Document loadDocument(final String uri) {
		return sharedContext.getUac().getXMLResource(uri).getDocument();
	}

	private LayoutContext newLayoutContext() {
		LayoutContext result = sharedContext.newLayoutContextInstance();
		result.setFontContext(new Java2DFontContext(outputDevice.getGraphics()));

		sharedContext.getTextRenderer().setup(result.getFontContext());

		return result;
	}

	private void init(float dotsPerPoint, int dotsPerPixel) {
		this.dotsPerPoint = dotsPerPoint;

		outputImage = ImageUtil.createCompatibleBufferedImage(DEFAULT_DOTS_PER_POINT, DEFAULT_DOTS_PER_POINT);
		outputDevice = new Java2DOutputDevice(outputImage);

		UserAgentCallback userAgent = new NaiveUserAgent();
		sharedContext = new SharedContext(userAgent);

		AWTFontResolver fontResolver = new AWTFontResolver();
		sharedContext.setFontResolver(fontResolver);

		SwingReplacedElementFactory replacedElementFactory = new SwingReplacedElementFactory();
		sharedContext.setReplacedElementFactory(replacedElementFactory);

		sharedContext.setTextRenderer(new Java2DTextRenderer());
		sharedContext.setDPI(72 * this.dotsPerPoint);
		sharedContext.setDotsPerPixel(dotsPerPixel);
		sharedContext.setPrint(false);
		sharedContext.setInteractive(false);
	}

	private static final class NullUserInterface implements UserInterface {

		public boolean isHover(Element e) {
			return false;
		}

		public boolean isActive(Element e) {
			return false;
		}

		public boolean isFocus(Element e) {
			return false;
		}
	}
}