Question

我正在使用Pdfbox从pdf文件中搜索单词（或字符串），我也想知道该单词的坐标。例如： - 在pdf文件中有一个字符串，如＆＃34; $ {abc}＆＃34;。我想知道这个字符串的坐标。我尝试了几个例子，但根据我没有得到结果。结果它显示了角色的坐标。

这是代码

@Override
protected void writeString(String string, List<TextPosition> textPositions) throws IOException {
    for(TextPosition text : textPositions) {


        System.out.println( "String[" + text.getXDirAdj() + "," +
                text.getYDirAdj() + " fs=" + text.getFontSize() + " xscale=" +
                text.getXScale() + " height=" + text.getHeightDir() + " space=" +
                text.getWidthOfSpace() + " width=" +
                text.getWidthDirAdj() + "]" + text.getUnicode());

    }
}

我正在使用pdfbox 2.0

Answer 1

PDFBox＆＃39;的最后一种方法PDFTextStripper类仍然具有位置的文本（在缩减为纯文本之前）是方法

/**
 * Write a Java string to the output stream. The default implementation will ignore the <code>textPositions</code>
 * and just calls {@link #writeString(String)}.
 *
 * @param text The text to write to the stream.
 * @param textPositions The TextPositions belonging to the text.
 * @throws IOException If there is an error when writing the text.
 */
protected void writeString(String text, List<TextPosition> textPositions) throws IOException

应该在此拦截，因为此方法接收预处理的，特别是排序的 TextPosition对象（如果请求排序开始）。

（实际上我更倾向于在调用方法writeLine中拦截，根据其参数和局部变量的名称，它具有行的所有TextPosition个实例每writeString调用一次word;不幸的是，PDFBox开发人员已将此方法声明为私有...好吧，也许这会在最终的2.0.0发布之前发生变化... nudge，nudge 。更新：不幸的是它在发布中没有改变...... 叹息）

此外，使用辅助类将TextPosition个实例的序列包装在类似String的类中以使代码更清晰是有帮助的。

考虑到这一点，人们可以搜索像这样的变量

List<TextPositionSequence> findSubwords(PDDocument document, int page, String searchTerm) throws IOException
{
    final List<TextPositionSequence> hits = new ArrayList<TextPositionSequence>();
    PDFTextStripper stripper = new PDFTextStripper()
    {
        @Override
        protected void writeString(String text, List<TextPosition> textPositions) throws IOException
        {
            TextPositionSequence word = new TextPositionSequence(textPositions);
            String string = word.toString();

            int fromIndex = 0;
            int index;
            while ((index = string.indexOf(searchTerm, fromIndex)) > -1)
            {
                hits.add(word.subSequence(index, index + searchTerm.length()));
                fromIndex = index + 1;
            }
            super.writeString(text, textPositions);
        }
    };

    stripper.setSortByPosition(true);
    stripper.setStartPage(page);
    stripper.setEndPage(page);
    stripper.getText(document);
    return hits;
}

使用此助手类

public class TextPositionSequence implements CharSequence
{
    public TextPositionSequence(List<TextPosition> textPositions)
    {
        this(textPositions, 0, textPositions.size());
    }

    public TextPositionSequence(List<TextPosition> textPositions, int start, int end)
    {
        this.textPositions = textPositions;
        this.start = start;
        this.end = end;
    }

    @Override
    public int length()
    {
        return end - start;
    }

    @Override
    public char charAt(int index)
    {
        TextPosition textPosition = textPositionAt(index);
        String text = textPosition.getUnicode();
        return text.charAt(0);
    }

    @Override
    public TextPositionSequence subSequence(int start, int end)
    {
        return new TextPositionSequence(textPositions, this.start + start, this.start + end);
    }

    @Override
    public String toString()
    {
        StringBuilder builder = new StringBuilder(length());
        for (int i = 0; i < length(); i++)
        {
            builder.append(charAt(i));
        }
        return builder.toString();
    }

    public TextPosition textPositionAt(int index)
    {
        return textPositions.get(start + index);
    }

    public float getX()
    {
        return textPositions.get(start).getXDirAdj();
    }

    public float getY()
    {
        return textPositions.get(start).getYDirAdj();
    }

    public float getWidth()
    {
        TextPosition first = textPositions.get(start);
        TextPosition last = textPositions.get(end);
        return last.getWidthDirAdj() + last.getXDirAdj() - first.getXDirAdj();
    }

    final List<TextPosition> textPositions;
    final int start, end;
}

要仅输出其位置，宽度，最终字母和最终字母位置，您可以使用此

void printSubwords(PDDocument document, String searchTerm) throws IOException
{
    System.out.printf("* Looking for '%s'\n", searchTerm);
    for (int page = 1; page <= document.getNumberOfPages(); page++)
    {
        List<TextPositionSequence> hits = findSubwords(document, page, searchTerm);
        for (TextPositionSequence hit : hits)
        {
            TextPosition lastPosition = hit.textPositionAt(hit.length() - 1);
            System.out.printf("  Page %s at %s, %s with width %s and last letter '%s' at %s, %s\n",
                    page, hit.getX(), hit.getY(), hit.getWidth(),
                    lastPosition.getUnicode(), lastPosition.getXDirAdj(), lastPosition.getYDirAdj());
        }
    }
}

对于测试，我使用MS Word创建了一个小测试文件：

此测试的输出

@Test
public void testVariables() throws IOException
{
    try (   InputStream resource = getClass().getResourceAsStream("Variables.pdf");
            PDDocument document = PDDocument.load(resource);    )
    {
        System.out.println("\nVariables.pdf\n-------------\n");
        printSubwords(document, "${var1}");
        printSubwords(document, "${var 2}");
    }
}

是

Variables.pdf
-------------

* Looking for '${var1}'
  Page 1 at 164.39648, 158.06 with width 34.67856 and last letter '}' at 193.22, 158.06
  Page 1 at 188.75699, 174.13995 with width 34.58806 and last letter '}' at 217.49, 174.13995
  Page 1 at 167.49583, 190.21997 with width 38.000168 and last letter '}' at 196.22, 190.21997
  Page 1 at 176.67009, 206.18 with width 35.667114 and last letter '}' at 205.49, 206.18

* Looking for '${var 2}'
  Page 1 at 164.39648, 257.65997 with width 37.078552 and last letter '}' at 195.62, 257.65997
  Page 1 at 188.75699, 273.74 with width 37.108047 and last letter '}' at 220.01, 273.74
  Page 1 at 167.49583, 289.72998 with width 40.55017 and last letter '}' at 198.74, 289.72998
  Page 1 at 176.67778, 305.81 with width 38.059418 and last letter '}' at 207.89, 305.81

我有点意外，因为如果在一条线上找到了${var 2};毕竟，PDFBox代码让我假设方法writeString我覆盖只检索单词;它看起来好像检索线的较长部分而不仅仅是单词......

如果您需要分组TextPosition个实例中的其他数据，只需相应地增强TextPositionSequence。

Answer 2

如上所述，这不是您问题的答案，但下面是您如何在IText中执行此操作的一个框架示例。这并不是说在Pdfbox中也不可能。

基本上你创建一个接受＆＃34;解析事件的RenderListener＆＃34;当他们发生。您将此侦听器传递给PdfReaderContentParser.processContent。在聆听者的renderText方法中，您可以获得重建布局所需的所有信息，包括构成内容的x / y坐标和text / image / ....

RenderListener listener = new RenderListener() {
    @Override
    public void renderText(TextRenderInfo arg0) {
        LineSegment segment = arg0.getBaseline();
        int x = (int) segment.getStartPoint().get(Vector.I1);
        // smaller Y means closer to the BOTTOM of the page. So we negate the Y to get proper top-to-bottom ordering
        int y = -(int) segment.getStartPoint().get(Vector.I2);
        int endx = (int) segment.getEndPoint().get(Vector.I1);
        log.debug("renderText "+x+".."+endx+"/"+y+": "+arg0.getText());
        ...
    }

    ... // other overrides
};

PdfReaderContentParser p = new PdfReaderContentParser(reader);
for (int i = 1; i <= reader.getNumberOfPages(); i++) {
    log.info("handling page "+i);
    p.processContent(i, listener);
}

Answer 3

我正在寻找高亮显示PDF文件中的不同单词。为此，我需要正确地知道单词坐标，所以我正在做的是从左上角（第一个字母）获得（x，y）坐标，从最后一个字母获得（x，y）坐标。右上角的字母。

稍后，将点保存在一个数组中。请记住，由于给出了坐标，为了正确获取y坐标，您需要相对于页面大小的相对位置。但是getYDirAdj()方法是绝对的，很多时间与页面中的方法不匹配。

protected void writeString(String string, List<TextPosition> textPositions) throws IOException {
    boolean isFound = false;
    float posXInit  = 0, 
          posXEnd   = 0, 
          posYInit  = 0,
          posYEnd   = 0,
          width     = 0, 
          height    = 0, 
          fontHeight = 0;
    String[] criteria = {"Word1", "Word2", "Word3", ....};

    for (int i = 0; i < criteria.length; i++) {
        if (string.contains(criteria[i])) {
            isFound = true;
        } 
    }
    if (isFound) {
        posXInit = textPositions.get(0).getXDirAdj();
        posXEnd  = textPositions.get(textPositions.size() - 1).getXDirAdj() + textPositions.get(textPositions.size() - 1).getWidth();
        posYInit = textPositions.get(0).getPageHeight() - textPositions.get(0).getYDirAdj();
        posYEnd  = textPositions.get(0).getPageHeight() - textPositions.get(textPositions.size() - 1).getYDirAdj();
        width    = textPositions.get(0).getWidthDirAdj();
        height   = textPositions.get(0).getHeightDir();

        System.out.println(string + "X-Init = " + posXInit + "; Y-Init = " + posYInit + "; X-End = " + posXEnd + "; Y-End = " + posYEnd + "; Font-Height = " + fontHeight);

        float quadPoints[] = {posXInit, posYEnd + height + 2, posXEnd, posYEnd + height + 2, posXInit, posYInit - 2, posXEnd, posYEnd - 2};

        List<PDAnnotation> annotations = document.getPage(this.getCurrentPageNo() - 1).getAnnotations();
        PDAnnotationTextMarkup highlight = new PDAnnotationTextMarkup(PDAnnotationTextMarkup.SUB_TYPE_HIGHLIGHT);

        PDRectangle position = new PDRectangle();
        position.setLowerLeftX(posXInit);
        position.setLowerLeftY(posYEnd);
        position.setUpperRightX(posXEnd);
        position.setUpperRightY(posYEnd + height);

        highlight.setRectangle(position);

        // quadPoints is array of x,y coordinates in Z-like order (top-left, top-right, bottom-left,bottom-right) 
        // of the area to be highlighted

        highlight.setQuadPoints(quadPoints);

        PDColor yellow = new PDColor(new float[]{1, 1, 1 / 255F}, PDDeviceRGB.INSTANCE);
        highlight.setColor(yellow);
        annotations.add(highlight);
    }
}

如何搜索某些特定的字符串或单词，并在java中的pdf文档中进行坐标

3 个答案: