Can we use text extraction strategy after applying location extraction strategy in itextpdf?

问题

I used the following code to get data in PDF from a particular location. I want to get bold text present in that location.

Rectangle rect = new Rectangle(0,0,250,250);
RenderFilter filter = new RegiontextRenderFilter(rect);
fontBasedTextExtractionStrategy strategy = new fontBasedTextExtractionStrategy();
strategy = new FilteredTextRenderListener(new LocationTextExtractionStrategy(), filter); //Throws Error.

To start with, creating a new method called fontBasedTextExtractionStrategy instead of text simple TextExtractionStrategy help? Something like below

 public class fontBasedTextExtractionStrategy implements TextExtractionStrategy {
    private String text;

    @Override
    public void beginTextBlock() {
    }

    @Override
    public void renderText(TextRenderInfo renderInfo) {
        text = renderInfo.getText();

        System.out.println(renderInfo.getFont().getFontType());

        System.out.print(text);
    }

    @Override
    public void endTextBlock() {
    }

    @Override
    public void renderImage(ImageRenderInfo renderInfo) {
    }

    @Override
    public String getResultantText() {
        return text;
    }
}

But again how to call it properly?

回答1:

Please take a look at the ParseCustom example. In this example, we create a custom RenderFilter (not a TextExtractionStrategy):

class FontRenderFilter extends RenderFilter {
    public boolean allowText(TextRenderInfo renderInfo) {
        String font = renderInfo.getFont().getPostscriptFontName();
        return font.endsWith("Bold") || font.endsWith("Oblique");
    }
}

This text will filter all text so that only text of which the Postscript font name ends with Bold or Oblique.

This is how you use this filter:

public void parse(String filename) throws IOException {
    PdfReader reader = new PdfReader(filename);
    Rectangle rect = new Rectangle(36, 750, 559, 806);
    RenderFilter regionFilter = new RegionTextRenderFilter(rect);
    FontRenderFilter fontFilter = new FontRenderFilter();
    TextExtractionStrategy strategy = new FilteredTextRenderListener(
            new LocationTextExtractionStrategy(), regionFilter, fontFilter);
    System.out.println(PdfTextExtractor.getTextFromPage(reader, 1, strategy));
    reader.close();
}

As you can see, we create a FilteredTextRenderListener that takes two filters, a RegionTextRenderFilter and our self-made filter based on the font.

来源：https://stackoverflow.com/questions/24506830/can-we-use-text-extraction-strategy-after-applying-location-extraction-strategy

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java

itext