src/java/org/apache/fop/render/ps/AbstractPSTranscoder.java

/*
 * Copyright 1999-2004 The Apache Software Foundation.
 * 
 * Licensed 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.
 */

/* $Id$ */
 
package org.apache.fop.render.ps;


import java.awt.Color;

import java.io.IOException;

import org.apache.avalon.framework.configuration.Configuration;
import org.apache.avalon.framework.container.ContainerUtil;
import org.apache.batik.bridge.BridgeContext;
import org.apache.batik.bridge.UnitProcessor;
import org.apache.batik.transcoder.TranscoderException;
import org.apache.batik.transcoder.TranscoderOutput;

import org.apache.batik.transcoder.image.ImageTranscoder;

import org.apache.fop.svg.AbstractFOPTranscoder;

import org.w3c.dom.Document;
import org.w3c.dom.svg.SVGLength;

/**
 * This class enables to transcode an input to a PostScript document.
 *
 * <p>Two transcoding hints (<tt>KEY_WIDTH</tt> and
 * <tt>KEY_HEIGHT</tt>) can be used to respectively specify the image
 * width and the image height. If only one of these keys is specified,
 * the transcoder preserves the aspect ratio of the original image.
 *
 * <p>The <tt>KEY_BACKGROUND_COLOR</tt> defines the background color
 * to use for opaque image formats, or the background color that may
 * be used for image formats that support alpha channel.
 *
 * <p>The <tt>KEY_AOI</tt> represents the area of interest to paint
 * in device space.
 *
 * <p>Three additional transcoding hints that act on the SVG
 * processor can be specified:
 *
 * <p><tt>KEY_LANGUAGE</tt> to set the default language to use (may be
 * used by a &lt;switch> SVG element for example),
 * <tt>KEY_USER_STYLESHEET_URI</tt> to fix the URI of a user
 * stylesheet, and <tt>KEY_PIXEL_TO_MM</tt> to specify the pixel to
 * millimeter conversion factor.
 *
 * @author <a href="mailto:keiron@aftexsw.com">Keiron Liddle</a>
 * @author <a href="mailto:jeremias@apache.org">Jeremias Maerki</a>
 * @version $Id$
 */
public abstract class AbstractPSTranscoder extends AbstractFOPTranscoder {

    private   Configuration                cfg      = null;
    protected AbstractPSDocumentGraphics2D graphics = null;

    /**
     * Constructs a new <tt>AbstractPSTranscoder</tt>.
     */
    public AbstractPSTranscoder() {
        super();
    }

    protected abstract AbstractPSDocumentGraphics2D createDocumentGraphics2D();

    /**
     * Transcodes the specified Document as an image in the specified output.
     *
     * @param document the document to transcode
     * @param uri the uri of the document or null if any
     * @param output the ouput where to transcode
     * @exception TranscoderException if an error occured while transcoding
     */
    protected void transcode(Document document, String uri,
                             TranscoderOutput output) 
        throws TranscoderException {

        graphics = createDocumentGraphics2D();
        
        try {
            if (this.cfg != null) {
                ContainerUtil.configure(graphics, this.cfg);
            }
            ContainerUtil.initialize(graphics);
        } catch (Exception e) {
            throw new TranscoderException(
                "Error while setting up PDFDocumentGraphics2D", e);
        }

        super.transcode(document, uri, output);

        getLogger().trace("document size: " + width + " x " + height);
        
        // prepare the image to be painted
        UnitProcessor.Context uctx = UnitProcessor.createContext(ctx, 
                    document.getDocumentElement());
        float widthInPt = UnitProcessor.userSpaceToSVG(width, SVGLength.SVG_LENGTHTYPE_PT, 
                    UnitProcessor.HORIZONTAL_LENGTH, uctx);
        int w = (int)(widthInPt + 0.5);
        float heightInPt = UnitProcessor.userSpaceToSVG(height, SVGLength.SVG_LENGTHTYPE_PT, 
                UnitProcessor.HORIZONTAL_LENGTH, uctx);
        int h = (int)(heightInPt + 0.5);
        getLogger().trace("document size: " + w + "pt x " + h + "pt");
        

        try {
            graphics.setupDocument(output.getOutputStream(), w, h);
            graphics.setSVGDimension(width, height);

            if (hints.containsKey(ImageTranscoder.KEY_BACKGROUND_COLOR)) {
                graphics.setBackgroundColor
                    ((Color)hints.get(ImageTranscoder.KEY_BACKGROUND_COLOR));
        }
            graphics.setGraphicContext
                (new org.apache.batik.ext.awt.g2d.GraphicContext());
            graphics.setTransform(curTxf);

            this.root.paint(graphics);

            graphics.finish();
        } catch (IOException ex) {
            throw new TranscoderException(ex);
        }
    }

    protected BridgeContext createBridgeContext() {
        /*boolean stroke = true;
        if (hints.containsKey(KEY_STROKE_TEXT)) {
            stroke = ((Boolean)hints.get(KEY_STROKE_TEXT)).booleanValue();
        }*/

        BridgeContext ctx = new BridgeContext(userAgent);
        PSTextPainter textPainter = new PSTextPainter(graphics.getFontInfo());
        ctx.setTextPainter(textPainter);
        ctx.putBridge(new PSTextElementBridge(textPainter));

        //ctx.putBridge(new PSImageElementBridge());
        return ctx;
    }


}