I am trying to reduce a size of PDF using iText. In my code I resize the existing images. I found an example of the code at http://itextpdf.com/examples/iia.php?id=286 and modified it. It's reducing the size but the images are returned as jpg, so they have a white background. Obviously JPG does not support transparency. I've changed the code to write back as png image and some other things (like DCTDECODE filter to FLATEDECODE and BufferedImage.TYPE_INT_RGB to ARGB). But it's not working. Pdf can't be open (Insufficient data for an image). Any ideas what am I missing? Here is my code:
float FACTOR = 0.5f;
PdfReader reader = new PdfReader(src);
int n = reader.getXrefSize();
PdfObject object;
PRStream stream;
for (int i = 0; i < n; i++) {
object = reader.getPdfObject(i);
if (object == null || !object.isStream())
continue;
stream = (PRStream)object;
PdfObject pdfsubtype = stream.get(PdfName.SUBTYPE);
if (pdfsubtype != null && pdfsubtype.toString().equals(PdfName.IMAGE.toString())) {
PdfImageObject image = new PdfImageObject(stream);
BufferedImage bi = image.getBufferedImage();
if (bi == null) continue;
int width = (int)(bi.getWidth() * FACTOR);
int height = (int)(bi.getHeight() * FACTOR);
BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
AffineTransform at = AffineTransform.getScaleInstance(FACTOR, FACTOR);
Graphics2D g = img.createGraphics();
g.drawRenderedImage(bi, at);
ByteArrayOutputStream imgBytes = new ByteArrayOutputStream();
ImageIO.write(img, "png", imgBytes);
g.dispose();
stream.clear();
stream.setData(imgBytes.toByteArray(), false, PRStream.BEST_COMPRESSION);
stream.put(PdfName.TYPE, PdfName.XOBJECT);
stream.put(PdfName.SUBTYPE, PdfName.IMAGE);
stream.put(PdfName.FILTER, PdfName.FLATEDECODE);
stream.put(PdfName.WIDTH, new PdfNumber(width));
stream.put(PdfName.HEIGHT, new PdfNumber(height));
stream.put(PdfName.BITSPERCOMPONENT, new PdfNumber(8));
stream.put(PdfName.COLORSPACE, PdfName.DEVICERGB);
imgBytes.flush();
imgBytes.close();
}
}
PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
stamper.close();
reader.close();
