# PDStrikeoutAppearanceHandler.java

    /*
     * Copyright 2018 The Apache Software Foundation.
     *
     * 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.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.pdmodel.common.PDRectangle;
    import org.apache.pdfbox.pdmodel.graphics.color.PDColor;
    import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotation;
    import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationStrikeout;
    import org.apache.pdfbox.pdmodel.PDAppearanceContentStream;
    import org.apache.pdfbox.pdmodel.PDDocument;

    /**
     *
     */
    public class PDStrikeoutAppearanceHandler extends PDAbstractAppearanceHandler
    {
        private static final Log LOG = LogFactory.getLog(PDStrikeoutAppearanceHandler.class);

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

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

        @Override
        public void generateNormalAppearance()
        {
            PDAnnotationStrikeout annotation = (PDAnnotationStrikeout) getAnnotation();
            PDRectangle rect = annotation.getRectangle();
            if (rect == null)
            {
                return;
            }
            float[] pathsArray = annotation.getQuadPoints();
            if (pathsArray == null)
            {
                return;
            }
            AnnotationBorder ab = AnnotationBorder.getAnnotationBorder(annotation, annotation.getBorderStyle());
            PDColor color = annotation.getColor();
            if (color == null || color.getComponents().length == 0)
            {
                return;
            }
            if (Float.compare(ab.width, 0) == 0)
            {
                // value found in adobe reader
                ab.width = 1.5f;
            }

            // Adjust rectangle even if not empty, see PLPDF.com-MarkupAnnotations.pdf
            //TODO in a class structure this should be overridable
            // this is similar to polyline but different data type
            float minX = Float.MAX_VALUE;
            float minY = Float.MAX_VALUE;
            float maxX = Float.MIN_VALUE;
            float maxY = Float.MIN_VALUE;
            for (int i = 0; i < pathsArray.length / 2; ++i)
            {
                float x = pathsArray[i * 2];
                float y = pathsArray[i * 2 + 1];
                minX = Math.min(minX, x);
                minY = Math.min(minY, y);
                maxX = Math.max(maxX, x);
                maxY = Math.max(maxY, y);
            }
            rect.setLowerLeftX(Math.min(minX - ab.width / 2, rect.getLowerLeftX()));
            rect.setLowerLeftY(Math.min(minY - ab.width / 2, rect.getLowerLeftY()));
            rect.setUpperRightX(Math.max(maxX + ab.width / 2, rect.getUpperRightX()));
            rect.setUpperRightY(Math.max(maxY + ab.width / 2, rect.getUpperRightY()));
            annotation.setRectangle(rect);

            try (PDAppearanceContentStream cs = getNormalAppearanceAsContentStream())
            {
                setOpacity(cs, annotation.getConstantOpacity());

                cs.setStrokingColor(color);
                if (ab.dashArray != null)
                {
                    cs.setLineDashPattern(ab.dashArray, 0);
                }
                cs.setLineWidth(ab.width);

                // spec is incorrect
                // https://stackoverflow.com/questions/9855814/pdf-spec-vs-acrobat-creation-quadpoints
                for (int i = 0; i < pathsArray.length / 8; ++i)
                {
                    // get mid point between bounds, subtract the line width to approximate what Adobe is doing
                    // See e.g. CTAN-example-Annotations.pdf and PLPDF.com-MarkupAnnotations.pdf
                    // and https://bugs.ghostscript.com/show_bug.cgi?id=693664
                    // do the math for diagonal annotations with this weird old trick:
                    // https://stackoverflow.com/questions/7740507/extend-a-line-segment-a-specific-distance
                    float len0 = (float) (Math.sqrt(Math.pow(pathsArray[i * 8] - pathsArray[i * 8 + 4], 2) +
                                          Math.pow(pathsArray[i * 8 + 1] - pathsArray[i * 8 + 5], 2)));
                    float x0 = pathsArray[i * 8 + 4];
                    float y0 = pathsArray[i * 8 + 5];
                    if (Float.compare(len0, 0) != 0)
                    {
                        // only if both coordinates are not identical to avoid divide by zero
                        x0 += (pathsArray[i * 8] - pathsArray[i * 8 + 4]) / len0 * (len0 / 2 - ab.width);
                        y0 += (pathsArray[i * 8 + 1] - pathsArray[i * 8 + 5]) / len0 * (len0 / 2 - ab.width);
                    }
                    float len1 = (float) (Math.sqrt(Math.pow(pathsArray[i * 8 + 2] - pathsArray[i * 8 + 6], 2) +
                                          Math.pow(pathsArray[i * 8 + 3] - pathsArray[i * 8 + 7], 2)));
                    float x1 = pathsArray[i * 8 + 6];
                    float y1 = pathsArray[i * 8 + 7];
                    if (Float.compare(len1, 0) != 0)
                    {
                        // only if both coordinates are not identical to avoid divide by zero
                        x1 += (pathsArray[i * 8 + 2] - pathsArray[i * 8 + 6]) / len1 * (len1 / 2 - ab.width);
                        y1 += (pathsArray[i * 8 + 3] - pathsArray[i * 8 + 7]) / len1 * (len1 / 2 - ab.width);
                    }
                    cs.moveTo(x0, y0);
                    cs.lineTo(x1, y1);
                }
                cs.stroke();
            }
            catch (IOException ex)
            {
                LOG.error(ex);
            }
        }

        @Override
        public void generateRolloverAppearance()
        {
            // No rollover appearance generated
        }

        @Override
        public void generateDownAppearance()
        {
            // No down appearance generated
        }
    }