edu.umass.cs.iesl.pdf2meta.cli.extract.pdfbox.pagedrawer.Invoke.java Source code

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/*
 * 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.
 */
package edu.umass.cs.iesl.pdf2meta.cli.extract.pdfbox.pagedrawer;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.pdfbox.cos.COSBase;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.cos.COSStream;
import org.apache.pdfbox.pdfviewer.PageDrawer;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDResources;
import org.apache.pdfbox.pdmodel.graphics.PDGraphicsState;
import org.apache.pdfbox.pdmodel.graphics.xobject.PDXObject;
import org.apache.pdfbox.pdmodel.graphics.xobject.PDXObjectForm;
import org.apache.pdfbox.pdmodel.graphics.xobject.PDXObjectImage;
import org.apache.pdfbox.util.Matrix;
import org.apache.pdfbox.util.PDFOperator;
import org.apache.pdfbox.util.operator.OperatorProcessor;

import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.List;
import java.util.Map;

/**
 * Implementation of content stream operator for page drawer.
 *
 * @author <a href="mailto:ben@benlitchfield.com">Ben Litchfield</a>
 * @version $Revision: 1.4 $
 */
public class Invoke extends OperatorProcessor {

    /**
     * Log instance.
     */
    private static final Log log = LogFactory.getLog(Invoke.class);

    /**
     * process : Do : Paint the specified XObject (section 4.7).
     * @param operator The operator that is being executed.
     * @param arguments List
     * @throws java.io.IOException If there is an error invoking the sub object.
     */
    public void process(PDFOperator operator, List<COSBase> arguments) throws IOException {
        GraphicsAwarePDFStreamEngine drawer = (GraphicsAwarePDFStreamEngine) context;
        PDPage page = drawer.getPage();
        COSName objectName = (COSName) arguments.get(0);
        Map xobjects = drawer.getResources().getXObjects();
        PDXObject xobject = (PDXObject) xobjects.get(objectName.getName());
        if (xobject == null) {
            log.warn("Can't find the XObject for '" + objectName.getName() + "'");
        } else if (xobject instanceof PDXObjectImage) {
            PDXObjectImage image = (PDXObjectImage) xobject;
            try {
                image.setGraphicsState(drawer.getGraphicsState());
                BufferedImage awtImage = image.getRGBImage();
                if (awtImage == null) {
                    log.warn("getRGBImage returned NULL");
                    return;//TODO PKOCH
                }
                int imageWidth = awtImage.getWidth();
                int imageHeight = awtImage.getHeight();
                double pageHeight = drawer.getPageSize().getHeight();

                log.debug("imageWidth: " + imageWidth + "\t\timageHeight: " + imageHeight);

                Matrix ctm = drawer.getGraphicsState().getCurrentTransformationMatrix();
                float yScaling = ctm.getYScale();
                float angle = (float) Math.acos(ctm.getValue(0, 0) / ctm.getXScale());
                if (ctm.getValue(0, 1) < 0 && ctm.getValue(1, 0) > 0)
                    angle = (-1) * angle;
                ctm.setValue(2, 1, (float) (pageHeight - ctm.getYPosition() - Math.cos(angle) * yScaling));
                ctm.setValue(2, 0, (float) (ctm.getXPosition() - Math.sin(angle) * yScaling));
                // because of the moved 0,0-reference, we have to shear in the opposite direction
                ctm.setValue(0, 1, (-1) * ctm.getValue(0, 1));
                ctm.setValue(1, 0, (-1) * ctm.getValue(1, 0));
                AffineTransform ctmAT = ctm.createAffineTransform();
                ctmAT.scale(1f / imageWidth, 1f / imageHeight);
                drawer.drawImage(awtImage, ctmAT);
            } catch (Exception e) {
                e.printStackTrace();
                log.error(e, e);
            }
        } else if (xobject instanceof PDXObjectForm) {
            // save the graphics state
            context.getGraphicsStack().push((PDGraphicsState) context.getGraphicsState().clone());

            PDXObjectForm form = (PDXObjectForm) xobject;
            COSStream invoke = (COSStream) form.getCOSObject();
            PDResources pdResources = form.getResources();
            if (pdResources == null) {
                pdResources = page.findResources();
            }
            // if there is an optional form matrix, we have to
            // map the form space to the user space
            Matrix matrix = form.getMatrix();
            if (matrix != null) {
                Matrix xobjectCTM = matrix.multiply(context.getGraphicsState().getCurrentTransformationMatrix());
                context.getGraphicsState().setCurrentTransformationMatrix(xobjectCTM);
            }
            getContext().processSubStream(page, pdResources, invoke);

            // restore the graphics state
            context.setGraphicsState((PDGraphicsState) context.getGraphicsStack().pop());
        }
    }
}