Example usage for com.itextpdf.text.pdf PdfReader decodeBytes

Introduction

In this page you can find the example usage for com.itextpdf.text.pdf PdfReader decodeBytes.

Prototype

public static byte[] decodeBytes(byte[] b, final PdfDictionary streamDictionary,
        Map<PdfName, FilterHandlers.FilterHandler> filterHandlers) throws IOException 

Source Link

Document

Decode a byte[] applying the filters specified in the provided dictionary using the provided filter handlers.

Usage

From source file:org.gmdev.pdftrick.utils.CustomExtraImgReader.java

License:Open Source License

/**
 * Read a png image with if all other method fails
 * @param ref//from w  ww .j a  va  2 s. c om
 * @param resultFile
 * @return The BufferedImage obj
 * @throws IOException
 * @throws ImageReadException
 */
public static BufferedImage readIndexedPNG(int ref, String resultFile) throws IOException, ImageReadException {

    PdfReader reader = new PdfReader(resultFile);
    PRStream stream = (PRStream) reader.getPdfObject(ref);
    PdfDictionary dic = stream;
    byte[] content = PdfReader.getStreamBytesRaw(stream);

    int width = dic.getAsNumber(PdfName.WIDTH).intValue();
    int height = dic.getAsNumber(PdfName.HEIGHT).intValue();
    int pngBitDepth = dic.getAsNumber(PdfName.BITSPERCOMPONENT).intValue();

    PdfObject colorspace = dic.getDirectObject(PdfName.COLORSPACE);
    PdfArray decode = dic.getAsArray(PdfName.DECODE);
    PdfArray carray = (PdfArray) colorspace;
    PdfObject id2 = carray.getDirectObject(3);

    byte[] palette = null;
    if (id2 instanceof PdfString) {
        palette = ((PdfString) id2).getBytes();
    } else if (id2 instanceof PRStream) {
        palette = PdfReader.getStreamBytes(((PRStream) id2));
    }

    Map<PdfName, FilterHandlers.FilterHandler> handlers = new HashMap<PdfName, FilterHandlers.FilterHandler>(
            FilterHandlers.getDefaultFilterHandlers());
    byte[] imageBytes = PdfReader.decodeBytes(content, dic, handlers);

    int stride = (width * pngBitDepth + 7) / 8;
    ByteArrayOutputStream ms = new ByteArrayOutputStream();
    PngWriter png = new PngWriter(ms);

    if (decode != null) {
        if (pngBitDepth == 1) {
            // if the decode array is 1,0, then we need to invert the image
            if (decode.getAsNumber(0).intValue() == 1 && decode.getAsNumber(1).intValue() == 0) {
                int len = imageBytes.length;
                for (int t = 0; t < len; ++t) {
                    imageBytes[t] ^= 0xff;
                }
            } else {
                // if the decode array is 0,1, do nothing.  It's possible that the array could be 0,0 or 1,1 - but that would be silly, so we'll just ignore that case
            }
        } else {
            // todo: add decode transformation for other depths
        }
    }
    int pngColorType = 0;
    png.writeHeader(width, height, pngBitDepth, pngColorType);

    if (palette != null) {
        png.writePalette(palette);
    }
    png.writeData(imageBytes, stride);
    png.writeEnd();

    imageBytes = ms.toByteArray();

    InputStream in = new ByteArrayInputStream(imageBytes);
    ImageInputStream ima_stream = ImageIO.createImageInputStream(in);

    BufferedImage buffImg = null;
    BufferedImage buffPic = ImageIO.read(ima_stream);

    // check if image contains a mask image ... experimental for this type of image
    BufferedImage buffMask = null;
    PRStream maskStream = (PRStream) dic.getAsStream(PdfName.SMASK);
    if (maskStream != null) {
        PdfImageObject maskImage = new PdfImageObject(maskStream);
        buffMask = maskImage.getBufferedImage();

        Image img = PdfTrickUtils.TransformGrayToTransparency(buffMask);
        buffImg = PdfTrickUtils.ApplyTransparency(buffPic, img);
    } else {
        buffImg = buffPic;
    }

    reader.close();
    ms.close();
    in.close();
    return buffImg;
}

---