org.obiba.mica.PdfUtils.java Source code

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Here is the source code for org.obiba.mica.PdfUtils.java

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/*
 * Copyright (c) 2018 OBiBa. All rights reserved.
 *
 * This program and the accompanying materials
 * are made available under the terms of the GNU Public License v3.0.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.obiba.mica;

import java.io.IOException;
import java.io.OutputStream;
import java.util.List;
import java.util.Map;
import java.util.Set;

import com.google.common.base.Throwables;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.Image;
import com.itextpdf.text.pdf.AcroFields;
import com.itextpdf.text.pdf.PdfContentByte;
import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.PdfStamper;

public class PdfUtils {

    private PdfUtils() {
    }

    public static void addImage(byte[] input, OutputStream output, Image image, String placeholder)
            throws IOException, DocumentException {
        try (PdfReaderAutoclosable pdfReader = new PdfReaderAutoclosable(input);
                PdfStamperAutoclosable pdfStamper = new PdfStamperAutoclosable(pdfReader, output)) {
            AcroFields form = pdfStamper.getAcroFields();
            List<AcroFields.FieldPosition> positions = form.getFieldPositions(placeholder);

            positions.forEach(p -> {
                image.scaleToFit(p.position.getWidth(), p.position.getHeight());
                image.setAbsolutePosition(
                        p.position.getLeft() + (p.position.getWidth() - image.getScaledWidth()) / 2,
                        p.position.getBottom() + (p.position.getHeight() - image.getScaledHeight()) / 2);
                PdfContentByte cb = pdfStamper.getOverContent(p.page);

                try {
                    cb.addImage(image);
                } catch (DocumentException e) {
                    throw Throwables.propagate(e);
                }
            });
        }
    }

    public static Set<String> getFieldNames(byte[] input) throws IOException {
        try (PdfReaderAutoclosable pdfReader = new PdfReaderAutoclosable(input)) {
            return pdfReader.getAcroFields().getFields().keySet();
        }
    }

    public static void fillOutForm(byte[] input, OutputStream output, Map<String, Object> values)
            throws IOException, DocumentException {
        try (PdfReaderAutoclosable pdfReader = new PdfReaderAutoclosable(input);
                PdfStamperAutoclosable stamper = new PdfStamperAutoclosable(pdfReader, output)) {
            stamper.setFormFlattening(true);

            AcroFields fields = stamper.getAcroFields();

            values.forEach((k, v) -> {
                if (v instanceof Boolean)
                    setField(fields, k, (Boolean) v);
                else
                    setField(fields, k, v);
            });
        }
    }

    private static void setField(AcroFields fields, String key, Object value) {
        setField(fields, key, value.toString());
    }

    private static void setField(AcroFields fields, String key, Boolean value) {
        String[] states = fields.getAppearanceStates(key);
        if (states.length > 0)
            setField(fields, key, states.length > 1 ? states[value.booleanValue() ? 1 : 0] : states[0]);
    }

    private static void setField(AcroFields fields, String key, String value) {
        try {
            fields.setField(key, value);
        } catch (DocumentException | IOException e) {
            throw new RuntimeException("Error setting PDF field", e);
        }
    }

    private static class PdfReaderAutoclosable extends PdfReader implements AutoCloseable {
        public PdfReaderAutoclosable(byte[] pdfIn) throws IOException {
            super(pdfIn);
        }
    }

    private static class PdfStamperAutoclosable extends PdfStamper implements AutoCloseable {
        public PdfStamperAutoclosable(PdfReader reader, OutputStream os) throws IOException, DocumentException {
            super(reader, os);
        }
    }
}