pdfbox 2.0.2 > Calling of PageDrawer.processPage method caught exceptions

Extending PageDrawer didn’t really work, so I extended PDFGraphicsStreamEngine and here’s the result. I do some of the stuff that is done in PageDrawer. To collect lines, either evaluate the shape in strokePath(), or collect points and lines in the other methods where I have included a println.

public class LineCatcher extends PDFGraphicsStreamEngine
{
    private final GeneralPath linePath = new GeneralPath();
    private int clipWindingRule = -1;

    public LineCatcher(PDPage page)
    {
        super(page);
    }

    public static void main(String[] args) throws IOException
    {
        try (PDDocument document = PDDocument.load(new File("Test.pdf")))
        {
            PDPage page = document.getPage(0);
            LineCatcher test = new LineCatcher(page);
            test.processPage(page);
        }
    }

    @Override
    public void appendRectangle(Point2D p0, Point2D p1, Point2D p2, Point2D p3) throws IOException
    {
        System.out.println("appendRectangle");
        // to ensure that the path is created in the right direction, we have to create
        // it by combining single lines instead of creating a simple rectangle
        linePath.moveTo((float) p0.getX(), (float) p0.getY());
        linePath.lineTo((float) p1.getX(), (float) p1.getY());
        linePath.lineTo((float) p2.getX(), (float) p2.getY());
        linePath.lineTo((float) p3.getX(), (float) p3.getY());

        // close the subpath instead of adding the last line so that a possible set line
        // cap style isn't taken into account at the "beginning" of the rectangle
        linePath.closePath();
    }

    @Override
    public void drawImage(PDImage pdi) throws IOException
    {
    }

    @Override
    public void clip(int windingRule) throws IOException
    {
        // the clipping path will not be updated until the succeeding painting operator is called
        clipWindingRule = windingRule;

    }

    @Override
    public void moveTo(float x, float y) throws IOException
    {
        linePath.moveTo(x, y);
        System.out.println("moveTo");
    }

    @Override
    public void lineTo(float x, float y) throws IOException
    {
        linePath.lineTo(x, y);
        System.out.println("lineTo");
    }

    @Override
    public void curveTo(float x1, float y1, float x2, float y2, float x3, float y3) throws IOException
    {
        linePath.curveTo(x1, y1, x2, y2, x3, y3);
        System.out.println("curveTo");
    }

    @Override
    public Point2D getCurrentPoint() throws IOException
    {
        return linePath.getCurrentPoint();
    }

    @Override
    public void closePath() throws IOException
    {
        linePath.closePath();
    }

    @Override
    public void endPath() throws IOException
    {
        if (clipWindingRule != -1)
        {
            linePath.setWindingRule(clipWindingRule);
            getGraphicsState().intersectClippingPath(linePath);
            clipWindingRule = -1;
        }
        linePath.reset();

    }

    @Override
    public void strokePath() throws IOException
    {
        // do stuff
        System.out.println(linePath.getBounds2D());

        linePath.reset();
    }

    @Override
    public void fillPath(int windingRule) throws IOException
    {
        linePath.reset();
    }

    @Override
    public void fillAndStrokePath(int windingRule) throws IOException
    {
        linePath.reset();
    }

    @Override
    public void shadingFill(COSName cosn) throws IOException
    {
    }
}

Update 19.3.2019: See also follow-up answer by mkl here.