# PDCircleAppearanceHandler.java

    /*
     * 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 org.apache.pdfbox.pdmodel.interactive.annotation.handlers;

    import java.io.IOException;
    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    import org.apache.pdfbox.cos.COSArray;
    import org.apache.pdfbox.cos.COSBase;
    import org.apache.pdfbox.cos.COSNumber;
    import org.apache.pdfbox.pdmodel.common.PDRectangle;
    import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotation;
    import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationCircle;
    import org.apache.pdfbox.pdmodel.PDAppearanceContentStream;
    import org.apache.pdfbox.pdmodel.PDDocument;
    import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationMarkup;
    import org.apache.pdfbox.pdmodel.interactive.annotation.PDAppearanceStream;
    import org.apache.pdfbox.pdmodel.interactive.annotation.PDBorderStyleDictionary;
    import org.apache.pdfbox.pdmodel.interactive.annotation.PDBorderEffectDictionary;

    /**
     * Handler to generate the circle annotations appearance.
     *
     */
    public class PDCircleAppearanceHandler extends PDAbstractAppearanceHandler
    {
        private static final Log LOG = LogFactory.getLog(PDCircleAppearanceHandler.class);

        public PDCircleAppearanceHandler(PDAnnotation annotation)
        {
            super(annotation);
        }

        public PDCircleAppearanceHandler(PDAnnotation annotation, PDDocument document)
        {
            super(annotation, document);
        }

        @Override
        public void generateNormalAppearance()
        {
            float lineWidth = getLineWidth();
            PDAnnotationCircle annotation = (PDAnnotationCircle) getAnnotation();
            try (PDAppearanceContentStream contentStream = getNormalAppearanceAsContentStream())
            {
                boolean hasStroke = contentStream.setStrokingColorOnDemand(getColor());
                boolean hasBackground = contentStream
                        .setNonStrokingColorOnDemand(annotation.getInteriorColor());

                setOpacity(contentStream, annotation.getConstantOpacity());

                contentStream.setBorderLine(lineWidth, annotation.getBorderStyle(), annotation.getBorder());
                PDBorderEffectDictionary borderEffect = annotation.getBorderEffect();

                if (borderEffect != null && borderEffect.getStyle().equals(PDBorderEffectDictionary.STYLE_CLOUDY))
                {
                    CloudyBorder cloudyBorder = new CloudyBorder(contentStream,
                        borderEffect.getIntensity(), lineWidth, getRectangle());
                    cloudyBorder.createCloudyEllipse(annotation.getRectDifference());
                    annotation.setRectangle(cloudyBorder.getRectangle());
                    annotation.setRectDifference(cloudyBorder.getRectDifference());
                    PDAppearanceStream appearanceStream = annotation.getNormalAppearanceStream();
                    appearanceStream.setBBox(cloudyBorder.getBBox());
                    appearanceStream.setMatrix(cloudyBorder.getMatrix());
                }
                else
                {
                    // Acrobat applies a padding to each side of the bbox so the line is completely within
                    // the bbox.

                    PDRectangle borderBox = handleBorderBox(annotation, lineWidth);

                    // lower left corner
                    float x0 = borderBox.getLowerLeftX();
                    float y0 = borderBox.getLowerLeftY();
                    // upper right corner
                    float x1 = borderBox.getUpperRightX();
                    float y1 = borderBox.getUpperRightY();
                    // mid points
                    float xm = x0 + borderBox.getWidth() / 2;
                    float ym = y0 + borderBox.getHeight() / 2;
                    // see http://spencermortensen.com/articles/bezier-circle/
                    // the below number was calculated from sampling content streams
                    // generated using Adobe Reader
                    float magic = 0.55555417f;
                    // control point offsets
                    float vOffset = borderBox.getHeight() / 2 * magic;
                    float hOffset = borderBox.getWidth() / 2 * magic;

                    contentStream.moveTo(xm, y1);
                    contentStream.curveTo((xm + hOffset), y1, x1, (ym + vOffset), x1, ym);
                    contentStream.curveTo(x1, (ym - vOffset), (xm + hOffset), y0, xm, y0);
                    contentStream.curveTo((xm - hOffset), y0, x0, (ym - vOffset), x0, ym);
                    contentStream.curveTo(x0, (ym + vOffset), (xm - hOffset), y1, xm, y1);
                    contentStream.closePath();
                }

                contentStream.drawShape(lineWidth, hasStroke, hasBackground);
            }
            catch (IOException e)
            {
                LOG.error(e);
            }
        }

        @Override
        public void generateRolloverAppearance()
        {
            // TODO to be implemented
        }

        @Override
        public void generateDownAppearance()
        {
            // TODO to be implemented
        }

        /**
         * Get the line with of the border.
         *
         * Get the width of the line used to draw a border around the annotation.
         * This may either be specified by the annotation dictionaries Border
         * setting or by the W entry in the BS border style dictionary. If both are
         * missing the default width is 1.
         *
         * @return the line width
         */
        // TODO: according to the PDF spec the use of the BS entry is annotation
        // specific
        // so we will leave that to be implemented by individual handlers.
        // If at the end all annotations support the BS entry this can be handled
        // here and removed from the individual handlers.
        float getLineWidth()
        {
            PDAnnotationMarkup annotation = (PDAnnotationMarkup) getAnnotation();

            PDBorderStyleDictionary bs = annotation.getBorderStyle();

            if (bs != null)
            {
                return bs.getWidth();
            }

            COSArray borderCharacteristics = annotation.getBorder();
            if (borderCharacteristics.size() >= 3)
            {
                COSBase base = borderCharacteristics.getObject(2);
                if (base instanceof COSNumber)
                {
                    return ((COSNumber) base).floatValue();
                }
            }

            return 1;
        }
    }