In Qoppa’s PDF libraries, the page width and page height are returned in points at 72 dpi. Here are the simple formulas to convert the page size to inches, centimeters and millimeters.
// open PDF document
PDFImages pdfDoc = new PDFImages ("C:\\myfile.pdf", null);
// loop through pages
for (int count = 0; count < pdfDoc.getPageCount(); ++count)
{
// this is the cropped page size in points at 72 dpi
double pageWidth = pdfDoc.getDisplayWidth(count);
double pageHeight = pdfDoc.getDisplayHeight(count);
System.out.println("*** Page " + (count+1) + " ******");
System.out.println("*************************");
System.out.println("Page Size in Points at 72 dpi");
System.out.println("Page width " + pageWidth + "pt");
System.out.println("Page height " + pageHeight + "pt");
// size of the page in inches
System.out.println("*************************");
System.out.println("Page Size in Inches");
System.out.println("Page width in inches " + pageWidth / 72.0 + "in");
System.out.println("Page height in inches " + pageHeight / 72.0 + "in");
// size of the page in centimeters
System.out.println("*************************");
System.out.println("Page Size in Centimeters");
System.out.println("Page width " + pageWidth * 2.54 / 72.0 + "cm");
System.out.println("Page height " + pageHeight * 2.54 / 72.0 + "cm");
// size of the page in millimeters
System.out.println("*************************");
System.out.println("Page Size in Millimeters");
System.out.println("Page width " + pageWidth * 2.54 / 72.0 * 100 + "mm");
System.out.println("Page height " + pageHeight * 2.54 / 72.0 * 100 + "mm");
System.out.println("*************************");
Sample output for a Letter Size Page:
************************* Page Size in Points at 72 dpi Page width 612.0pt Page height 792.0pt ************************* Page Size in Inches Page width in inches 8.5in Page height in inches 11.0in ************************* Page Size in Centimeters Page width 21.59cm Page height 27.94cm ************************* Page Size in Millimeters Page width 2159.0mm Page height 2794.0mm *************************
