org.sejda.impl.itext.component.PdfRotator.java Source code

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Here is the source code for org.sejda.impl.itext.component.PdfRotator.java

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/*
 * Created on 06/jun/2010
 *
 * Copyright 2010 by Andrea Vacondio (andrea.vacondio@gmail.com).
 * 
 * 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. 
 */
package org.sejda.impl.itext.component;

import static org.sejda.model.rotation.Rotation.getRotation;

import java.util.Set;

import org.sejda.model.rotation.Rotation;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.lowagie.text.pdf.PdfDictionary;
import com.lowagie.text.pdf.PdfName;
import com.lowagie.text.pdf.PdfNumber;
import com.lowagie.text.pdf.PdfReader;

/**
 * Handles rotations on a given PdfReader
 * 
 * @author Andrea Vacondio
 * 
 */
public final class PdfRotator implements OngoingRotation {

    private static final Logger LOG = LoggerFactory.getLogger(PdfRotator.class);

    private PdfReader reader;
    private Rotation rotation;
    private Set<Integer> pages;

    private PdfRotator(Rotation rotation, Set<Integer> pages) {
        this.rotation = rotation;
        this.pages = pages;
    }

    /**
     * DSL entry point to apply a rotation to a set of pages
     * <p>
     * <code>applyRotation(rotation, pages).to(document);</code>
     * </p>
     * 
     * @param rotation
     * @param pages
     * @return the ongoing apply rotation exposing methods to set the reader you want to apply the rotation to.
     */
    public static OngoingRotation applyRotation(Rotation rotation, Set<Integer> pages) {
        return new PdfRotator(rotation, pages);
    }

    public void to(PdfReader reader) {
        this.reader = reader;
        executeRotation();
    }

    /**
     * Apply the rotation to the dictionary of the given {@link PdfReader}
     */
    private void executeRotation() {
        LOG.debug("Applying rotation of {} degrees to {} pages", rotation.getDegrees(), pages.size());
        for (int p : pages) {
            apply(p);
        }
    }

    /**
     * apply the rotation to the given page if necessary
     * 
     * @param pageNmber
     */
    private void apply(int pageNmber) {
        if (pages.contains(pageNmber)) {
            PdfDictionary dictionary = reader.getPageN(pageNmber);
            dictionary.put(PdfName.ROTATE, new PdfNumber(
                    rotation.addRotation(getRotation(reader.getPageRotation(pageNmber))).getDegrees()));
        }
    }
}