PDF article region identification - pdf

Question

Which PdfBox APIs can I use for identification of regions where a region is a rectangle encapsulating one article so that I can then extract the text of the article.
I am thinking of parsing the PDF content where large white space areas encapsulating text would be identified as regions.
Here is a code which extracts one region where the size and placement of the region is hard coded:
System.setProperty("sun.java2d.cmm", "sun.java2d.cmm.kcms.KcmsServiceProvider");
PDDocument pdf = PDDocument.load(new File("SevenPropertiesofHighlySecureDevices.pdf"));
PDFTextStripperByArea stripper = new PDFTextStripperByArea();
stripper.setSortByPosition(true);
// 1 pt is equal to 1/72 inch
Rectangle2D rectangle = new Rectangle2D.Double(0,0,200,200);
String regionName = "First Article Region";
stripper.addRegion(regionName, rectangle);
stripper.extractRegions(pdf.getPage(0));
LOGGER.info("getTextForRegion: \n{}", stripper.getTextForRegion(regionName));
If anyone is tempted to "scan" a PDF to find out where the white space areas are so that this information would be used to determine rectangular regions for the purpose of extraction of articles then I would like to let you know that it is very slow and unlikely usable:
System.setProperty("sun.java2d.cmm", "sun.java2d.cmm.kcms.KcmsServiceProvider");
PDDocument pdf = PDDocument.load(new File("4.pdf"));
PDPage page = pdf.getPage(1);
PDRectangle cropBox = page.getCropBox();
float docWidth = cropBox.getUpperRightX();
float docHeight = cropBox.getUpperRightY();
float recWidth = 10;
float rectHeight = 10;
float xStep = recWidth / 2;
float yStep = rectHeight / 2;
String regionName = "docScannerRegion";
String docLeftMarginIndicator = "|";
String docRightMarginIndicator = "|";
String nonTextArea = " ";
String textArea = "-";
PDFTextStripperByArea stripper = new PDFTextStripperByArea();
for (float y = 0; y < docHeight; y = y + yStep) {
System.out.print(docLeftMarginIndicator);
for(float x = 0; x < docWidth; x = x + xStep) {
stripper.addRegion(regionName, new Rectangle2D.Double(x, y, recWidth, rectHeight));
stripper.extractRegions(page);
String txt = stripper.getTextForRegion(regionName).trim();
if (StringUtils.isBlank(txt)) {
System.out.print(nonTextArea);
} else {
System.out.print(textArea);
}
}
System.out.println(docRightMarginIndicator);
}