Example usage for org.apache.pdfbox.contentstream PDFGraphicsStreamEngine PDFGraphicsStreamEngine

Introduction

In this page you can find the example usage for org.apache.pdfbox.contentstream PDFGraphicsStreamEngine PDFGraphicsStreamEngine.

Prototype

protected PDFGraphicsStreamEngine(PDPage page) 

Source Link

Document

Constructor.

Usage

From source file:org.geoserver.wms.map.PDFGetMapTest.java

License:Open Source License

/**
 * Returns the last tiling pattern found during a render of the PDF document. Can be used to extract
 * one tiling pattern that gets actually used to render shapes (meant to be used against a document
 * that only has a single tiling pattern)
 * //from w w  w.  j  a v  a 2  s  .c  om
 * @param pdfDocument
 * @return
 * @throws InvalidPasswordException
 * @throws IOException
 */
PDTilingPattern getTilingPattern(byte[] pdfDocument) throws InvalidPasswordException, IOException {
    // load the document using PDFBOX (iText is no good for parsing tiling patterns, mostly works
    // well for text and image extraction, spent a few hours trying to use it with no results)
    PDDocument doc = PDDocument.load(pdfDocument);
    PDPage page = doc.getPage(0);

    // use a graphics stream engine, it's the only thing I could find that parses the PDF
    // deep enough to allow catching the tiling pattern in parsed form 
    AtomicReference<PDTilingPattern> pattern = new AtomicReference<>();
    PDFStreamEngine engine = new PDFGraphicsStreamEngine(page) {

        @Override
        public void strokePath() throws IOException {
        }

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

        @Override
        public void moveTo(float x, float y) throws IOException {
        }

        @Override
        public void lineTo(float x, float y) throws IOException {
        }

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

        @Override
        public void fillPath(int windingRule) throws IOException {
        }

        @Override
        public void fillAndStrokePath(int windingRule) throws IOException {
        }

        @Override
        public void endPath() throws IOException {
        }

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

        @Override
        public void curveTo(float x1, float y1, float x2, float y2, float x3, float y3) throws IOException {
        }

        @Override
        public void closePath() throws IOException {
        }

        @Override
        public void clip(int windingRule) throws IOException {
        }

        @Override
        public void appendRectangle(Point2D p0, Point2D p1, Point2D p2, Point2D p3) throws IOException {
        }
    };

    // setup the tiling pattern trap
    engine.addOperator(new SetNonStrokingColorN() {

        @Override
        public void process(Operator operator, List<COSBase> arguments) throws IOException {
            super.process(operator, arguments);

            PDColor color = context.getGraphicsState().getNonStrokingColor();
            if (context.getGraphicsState().getNonStrokingColorSpace() instanceof PDPattern) {
                PDPattern colorSpace = (PDPattern) context.getGraphicsState().getNonStrokingColorSpace();
                PDAbstractPattern ap = colorSpace.getPattern(color);
                if (ap instanceof PDTilingPattern) {
                    pattern.set((PDTilingPattern) ap);
                }
            }
        }
    });
    // run it
    engine.processPage(page);

    return pattern.get();
}

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