iText - 获取文本片段的字体大小和系列

Question

我目前正在尝试从PDF文件中自动提取重要的关键字.我能够从PDF文档中获取文本信息.但现在我需要知道这些关键字具有哪种字体大小和字体系列.

我已经拥有以下代码:

主要

public static void main(String[] args) throws IOException {
    String src = "SEM_081145.pdf";

    PdfReader reader = new PdfReader(src);

    SemTextExtractionStrategy semTextExtractionStrategy = new SemTextExtractionStrategy();

    PrintWriter out = new PrintWriter(new FileOutputStream(src + ".txt"));
    Rectangle rect = new Rectangle(70, 80, 490, 580);
    RenderFilter filter = new RegionTextRenderFilter(rect);

    for (int i = 1; i <= reader.getNumberOfPages(); i++) {
        // strategy = new FilteredTextRenderListener(new LocationTextExtractionStrategy(), filter);
        out.println(PdfTextExtractor.getTextFromPage(reader, i, semTextExtractionStrategy));
    }
    out.flush();
    out.close();
}

我已经实现了TextExtraction策略SemTextExtractionStrategy,如下所示:

public class SemTextExtractionStrategy 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;
}
}

我可以得到FontType但没有方法来获取字体大小.还有其他方法或如何获取当前文本段的字体大小？

或者是否有其他库可以从TextSegments中提取字体大小？我已经看过PDFBox和PDFTextStream.来自Aspose的PDF共享软件库将完美地完成这项工作.但它非常昂贵,我需要使用开源项目.

Answer 1

感谢Alexis我可以将他的C#解决方案转换为Java代码:

text = renderInfo.getText();

Vector curBaseline = renderInfo.getBaseline().getStartPoint();
Vector topRight = renderInfo.getAscentLine().getEndPoint();

Rectangle rect = new Rectangle(curBaseline.get(0), curBaseline.get(1), topRight.get(0), topRight.get(1));
float curFontSize = rect.getHeight();

Answer 2

我在使用Alexis和Prine的解决方案时遇到了一些麻烦，因为它不能正确处理旋转的文本。所以这就是我要做的（抱歉，在Scala中）：

val x0 = info.getAscentLine.getEndPoint
val x1 = info.getBaseline.getStartPoint
val x2 = info.getBaseline.getEndPoint
val length1 = (x2.subtract(x1)).cross((x1.subtract(x0))).lengthSquared
val length2 = x2.subtract(x1).lengthSquared
(length1, length2) match {
  case (0, 0) => 0
  case _ => length1 / length2
}