Example usage for com.itextpdf.text.pdf PdfName DCTDECODE

Introduction

In this page you can find the example usage for com.itextpdf.text.pdf PdfName DCTDECODE.

Prototype

PdfName DCTDECODE

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Document

A name

Usage

From source file:org.h819.commons.file.MyPDFUtils.java

/**
 *  pdf ? pdf/*from w  ww. j a  va  2  s . c  o  m*/
 *
 * @param srcPdf      the original PDF
 * @param destPdf     the resulting PDF
 * @param imageFactor The multiplication factor for the image (?  imageFacto =0.5f)
 * @throws IOException
 * @throws DocumentException
 */
public static void compressPdf(File srcPdf, File destPdf, float imageFactor)
        throws IOException, DocumentException {

    PdfReader reader = new PdfReader(srcPdf.getAbsolutePath());
    int n = reader.getXrefSize();
    PdfObject object;
    PRStream stream;
    // Look for image and manipulate image stream
    for (int i = 0; i < n; i++) {
        object = reader.getPdfObject(i);
        if (object == null || !object.isStream())
            continue;
        stream = (PRStream) object;
        if (!PdfName.IMAGE.equals(stream.getAsName(PdfName.SUBTYPE)))
            continue;
        if (!PdfName.DCTDECODE.equals(stream.getAsName(PdfName.FILTER)))
            continue;
        PdfImageObject image = new PdfImageObject(stream);
        BufferedImage bi = image.getBufferedImage();
        if (bi == null)
            continue;
        int width = (int) (bi.getWidth() * imageFactor);
        int height = (int) (bi.getHeight() * imageFactor);
        if (width <= 0 || height <= 0)
            continue;
        BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        AffineTransform at = AffineTransform.getScaleInstance(imageFactor, imageFactor);
        Graphics2D g = img.createGraphics();
        g.drawRenderedImage(bi, at);
        ByteArrayOutputStream imgBytes = new ByteArrayOutputStream();
        ImageIO.write(img, "JPG", imgBytes);
        stream.clear();
        stream.setData(imgBytes.toByteArray(), false, PRStream.NO_COMPRESSION);
        stream.put(PdfName.TYPE, PdfName.XOBJECT);
        stream.put(PdfName.SUBTYPE, PdfName.IMAGE);
        stream.put(PdfName.FILTER, PdfName.DCTDECODE);
        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);
    }
    reader.removeUnusedObjects();
    // Save altered PDF
    PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(destPdf.getAbsolutePath()));
    stamper.setFullCompression();
    stamper.close();
    reader.close();
}

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