Could someone give me an example of how to extract

问题:

Could someone give me an example of how to extract coordinates for a 'word' with PDFBox

I am using this link to extract positions of individual characters: https://www.tutorialkart.com/pdfbox/how-to-extract-coordinates-or-position-of-characters-in-pdf/

I am using this link to extract words: https://www.tutorialkart.com/pdfbox/extract-words-from-pdf-document/

I am stuck getting coordinates for whole words.

回答1:

You can extract the coordinates of words by collecting all the TextPosition objects building a word and combining their bounding boxes.

Implementing this along the lines of the two tutorials you referenced, you can extend PDFTextStripper like this:

public class GetWordLocationAndSize extends PDFTextStripper {
    public GetWordLocationAndSize() throws IOException {
    }

    @Override
    protected void writeString(String string, List<TextPosition> textPositions) throws IOException {
        String wordSeparator = getWordSeparator();
        List<TextPosition> word = new ArrayList<>();
        for (TextPosition text : textPositions) {
            String thisChar = text.getUnicode();
            if (thisChar != null) {
                if (thisChar.length() >= 1) {
                    if (!thisChar.equals(wordSeparator)) {
                        word.add(text);
                    } else if (!word.isEmpty()) {
                        printWord(word);
                        word.clear();
                    }
                }
            }
        }
        if (!word.isEmpty()) {
            printWord(word);
            word.clear();
        }
    }

    void printWord(List<TextPosition> word) {
        Rectangle2D boundingBox = null;
        StringBuilder builder = new StringBuilder();
        for (TextPosition text : word) {
            Rectangle2D box = new Rectangle2D.Float(text.getXDirAdj(), text.getYDirAdj(), text.getWidthDirAdj(), text.getHeightDir());
            if (boundingBox == null)
                boundingBox = box;
            else
                boundingBox.add(box);
            builder.append(text.getUnicode());
        }
        System.out.println(builder.toString() + " [(X=" + boundingBox.getX() + ",Y=" + boundingBox.getY()
                 + ") height=" + boundingBox.getHeight() + " width=" + boundingBox.getWidth() + "]");
    }
}

(ExtractWordCoordinates inner class)

and run it like this:

PDDocument document = PDDocument.load(resource);
PDFTextStripper stripper = new GetWordLocationAndSize();
stripper.setSortByPosition( true );
stripper.setStartPage( 0 );
stripper.setEndPage( document.getNumberOfPages() );

Writer dummy = new OutputStreamWriter(new ByteArrayOutputStream());
stripper.writeText(document, dummy);

(ExtractWordCoordinates test testExtractWordsForGoodJuJu)

Applied to the apache.pdf example the tutorials use you get:

2017-8-6 [(X=26.004425048828125,Y=22.00372314453125) height=5.833024024963379 width=36.31868362426758]
Welcome [(X=226.44479370117188,Y=22.00372314453125) height=5.833024024963379 width=36.5999755859375]
to [(X=265.5881652832031,Y=22.00372314453125) height=5.833024024963379 width=8.032623291015625]
The [(X=276.1641845703125,Y=22.00372314453125) height=5.833024024963379 width=14.881439208984375]
Apache [(X=293.5890197753906,Y=22.00372314453125) height=5.833024024963379 width=29.848846435546875]
Software [(X=325.98126220703125,Y=22.00372314453125) height=5.833024024963379 width=35.271636962890625]
Foundation! [(X=363.7962951660156,Y=22.00372314453125) height=5.833024024963379 width=47.871429443359375]
Custom [(X=334.0334777832031,Y=157.6195068359375) height=4.546705722808838 width=25.03936767578125]
Search [(X=360.8929138183594,Y=157.6195068359375) height=4.546705722808838 width=22.702728271484375]