de.berber.kindle.annotator.lib.Annotation.java Source code

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Here is the source code for de.berber.kindle.annotator.lib.Annotation.java

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/*
 * Copyright 2011, Bernhard J. Berger
 *
 * 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 de.berber.kindle.annotator.lib;

import java.io.IOException;
import java.util.List;

import javax.annotation.Nonnegative;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;

import org.apache.commons.configuration.CompositeConfiguration;
import org.apache.log4j.Logger;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.graphics.color.PDGamma;
import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotation;
import org.apache.pdfbox.pdmodel.interactive.documentnavigation.outline.PDDocumentOutline;

/**
 * Parent of all annotations. An annotation belongs to a particular page and can
 * be converted into a {@link PDAnnotation}.
 * 
 * @author Bernhard J. Berger
 */
public abstract class Annotation {
    /**
     * The log instance
     */
    private final static Logger LOG = Logger.getLogger(Annotation.class);

    /**
     * Zero-based page number of the annotation
     */
    private final int page;

    /**
     * @return The page of the annotation
     */
    public int getPage() {
        return page;
    }

    /**
     * The default color of all annotations
     */
    protected String color = "#0000FF";

    /**
     * The default opacity of all annotations.
     */
    protected float opacity = 0.2f;

    /**
     * Creates a new annotation with a {@code configuration}, a {@code prefix}
     * for configuration lookups and a {@code page} number.
     */
    protected Annotation(final @Nonnull CompositeConfiguration configuration, final @Nonnull String prefix,
            final @Nonnegative int page) {
        this.page = page;
        color = configuration.getString(prefix + ".color", color);
        opacity = configuration.getFloat(prefix + ".opacity", opacity);
    }

    /**
     * Checks whether the current belongs to the page {@code currentPageNumber}
     * and adds the annotation in such an case.
     * 
     * @param currentPageNumber
     *            The page number of {@code page}.
     * @param documentOutline
     *            The pdf outline
     * @param page
     *            The pdf page.
     */
    @SuppressWarnings("unchecked")
    public void toPDAnnotation(final @Nonnegative int currentPageNumber,
            final @Nonnull PDDocumentOutline documentOutline, final @Nonnull PDPage page) {
        if (this.page != currentPageNumber) {
            return;
        }

        try {
            final List<PDAnnotation> annotations = ((List<PDAnnotation>) page.getAnnotations());
            final PDAnnotation annotation = toPDAnnotation(documentOutline, page);

            if (annotation != null) {
                annotations.add(annotation);
            }
        } catch (IOException e) {
            LOG.error("Cannot read annotations from PDF.");
        }
    }

    /**
     * Create a {@link PDAnnotation} for the current annotation.
     * 
     * @param documentOutline
     *            The document outline (needed for bookmarks).
     * @param page
     *            The current PDF page.
     * @return A new annotation or {@code null}.
     */
    protected abstract @Nullable PDAnnotation toPDAnnotation(final @Nonnull PDDocumentOutline documentOutline,
            final @Nonnull PDPage page);

    /**
     * Checks whether a multiplier is in the allowed page range.
     */
    protected static final void checkFactorValue(final double factor) {
        if (factor < 0.0 || factor > 1.0) {
            LOG.warn("Factor is out of visible range: " + factor);
        }
    }

    /**
     * Converts the color string into a PDGamma object.
     * 
     * @return
     */
    protected final PDGamma getColor() {
        assert color.length() == 7 && color.startsWith("#");
        final PDGamma color = new PDGamma();

        color.setR(Integer.parseInt(this.color.substring(1, 3), 16) / 255f);
        color.setG(Integer.parseInt(this.color.substring(3, 5), 16) / 255f);
        color.setB(Integer.parseInt(this.color.substring(5, 7), 16) / 255f);

        return color;
    }
}