pdfimage.java

一个java操作pdf文件的开发包,很好用的.

                            }
                            
                            int compressionMethod = is.read();
                            int filterMethod = is.read();
                            
                            int interlaceMethod = is.read();
                            if (interlaceMethod != 0) {
                                throw new BadPdfFormatException(errorID + " Interlace method " + interlaceMethod + " is not suported.");
                            }
                            
                            PdfDictionary decodeparms = new PdfDictionary();
                            decodeparms.put(PdfName.BITSPERCOMPONENT, new PdfNumber(bitDepth));
                            decodeparms.put(PdfName.PREDICTOR, new PdfNumber(15));
                            decodeparms.put(PdfName.COLUMNS, new PdfNumber(w));
                            decodeparms.put(PdfName.COLORS, new PdfNumber((colorType == 2) ? 3: 1));
                            put(PdfName.DECODEPARMS, decodeparms);
                            
                            Png.getInt(is);
                        }
                        else if (Png.PLTE.equals(marker)) {
                            if (colorType == 3) {
                                PdfArray colorspace = new PdfArray();
                                colorspace.add(PdfName.INDEXED);
                                colorspace.add(PdfName.DEVICERGB);
                                colorspace.add(new PdfNumber(len / 3 - 1));
                                ByteBuffer colortable = new ByteBuffer();
                                while ((len--) > 0) {
                                    colortable.append_i(is.read());
                                }
                                colorspace.add(new PdfString(colortable.toByteArray()));
                                put(PdfName.COLORSPACE, colorspace);
                                Png.getInt(is);
                            }
                            else {
                                Image.skip(is, len + 4);
                            }
                        }
                        else if (Png.IEND.equals(marker)) {
                            break;
                        }
                        else {
                            for (int j = -4; j < len; j++) {
                                is.read();
                            }
                        }
                        
                    }
                    break;
                case Image.JPEG:
                    put(PdfName.FILTER, PdfName.DCTDECODE);
                    switch(image.colorspace()) {
                        case 1:
                            put(PdfName.COLORSPACE, PdfName.DEVICEGRAY);
                            break;
                        case 3:
                            put(PdfName.COLORSPACE, PdfName.DEVICERGB);
                            break;
                        default:
                            put(PdfName.COLORSPACE, PdfName.DEVICECMYK);
                            if (image.isInvertedJPEG()) {
                                put(PdfName.DECODE, new PdfLiteral("[1 0 1 0 1 0 1 0]"));
                            }
                    }
                    put(PdfName.BITSPERCOMPONENT, new PdfNumber(8));
                    if (image.rawData() != null){
                        bytes = image.rawData();
                        streamBytes = null;
                        put(PdfName.LENGTH, new PdfNumber(bytes.length));
                        return;
                    }
                    transferBytes(is, streamBytes, -1);
                    break;
                case Image.GIF:
                    // HEADER + INFO + COLORTABLE
                    
                    // Byte 0-2: header
                    // checks if the file really is a GIF-file
                    if (is.read() != 'G' || is.read() != 'I' || is.read() != 'F') {
                        throw new BadPdfFormatException(errorID + " is not a GIF-file (GIF header not found).");
                    }
                    
                    put(PdfName.FILTER, PdfName.LZWDECODE);
                    
                    PdfDictionary decodeparms = new PdfDictionary();
                    decodeparms.put(PdfName.EARLYCHANGE, new PdfNumber(0));
                    put(PdfName.DECODEPARMS, decodeparms);
                    
                    PdfArray colorspace = new PdfArray();
                    colorspace.add(PdfName.INDEXED);
                    colorspace.add(PdfName.DEVICERGB);
                    // Byte 3-5: version
                    // Byte 6-7: logical screen width
                    // Byte 8-9: logical screen height
                    // Byte 10: Packed Fields
                    for (int j = 0; j < 8; j++) {
                        i = is.read();
                    }
                    // Byte 10: bit 1: Global Color Table Flag
                    if ((i & 0x80) == 0) {
                        throw new BadPdfFormatException(errorID + " is not a supported GIF-file (there is no global color table present).");
                    }
                    // Byte 10: bit 6-8: Size of Global Color Table
                    int nColors = 1 << ((i & 7) + 1);
                    colorspace.add(new PdfNumber(nColors - 1));
                    // Byte 11: Background color index
                    is.read();
                    // Byte 12: Pixel aspect ratio
                    is.read();
                    // Byte 13-...: Global color table
                    ByteBuffer colortable = new ByteBuffer();
                    for (int j = 0; j < nColors; j++) {
                        colortable.append_i(is.read());	// red
                        colortable.append_i(is.read());	// green
                        colortable.append_i(is.read());	// blue
                    }
                    colorspace.add(new PdfString(colortable.toByteArray()));
                    put(PdfName.COLORSPACE, colorspace);
                    put(PdfName.BITSPERCOMPONENT, new PdfNumber(8));
                    
                    // IMAGE DESCRIPTOR
                    
                    // Byte 0: Image separator
                    // only simple gif files with image immediate following global color table are supported
                    // 0x2c is a fixed value for the image separator
                    if (is.read() != 0x2c) {
                        throw new BadPdfFormatException(errorID + " is not a supported GIF-file (the image separator '0x2c' is not found after reading the color table).");
                    }
                    // Byte 1-2: Image Left Position
                    // Byte 3-4: Image Top Position
                    // Byte 5-6: Image Width
                    // Byte 7-8: Image Height
                    // ignore position and size
                    for (int j = 0; j < 8; j++) {
                        is.read();
                    }
                    // Byte 9: Packed Fields
                    // Byte 9: bit 1: Local Color Table Flag
                    // Byte 9: bit 2: Interlace Flag
                    if ((is.read() & 0xc0) > 0) {
                        throw new BadPdfFormatException(errorID + " is not a supported GIF-file (interlaced gifs or gifs using local color table can't be inserted).");
                    }
                    
                    // Byte 10: LZW initial code
                    if (is.read() != 0x08) {
                        throw new BadPdfFormatException(errorID + " is not a supported GIF-file (initial LZW code not supported).");
                    }
                    // Read the Image Data
                    int code = 0;
                    int codelength = 9;
                    int tablelength = 257;
                    int bitsread = 0;
                    int bitstowrite = 0;
                    int bitsdone = 0;
                    int bitsleft = 23;
                    int bytesdone = 0;
                    int bytesread = 0;
                    int byteswritten = 0;
                    // read the size of the first Data Block
                    int size = is.read();
                    // Check if there is any data in the GIF
                    if (size < 1) {
                        throw new BadPdfFormatException(errorID + " is not a supported GIF-file. (no image data found).");
                    }
                    // if possible, we read the first 24 bits of data
                    size--; bytesread++; bitsread = is.read();
                    if (size > 0) {
                        size--; bytesread++; bitsread += (is.read() << 8);
                        if (size > 0) {
                            size--; bytesread++; bitsread += (is.read() << 16);
                        }
                    }
                    while (bytesread > byteswritten) {
                        tablelength++;
                        // we extract a code with length=codelength
                        code = (bitsread >> bitsdone) & ((1 << codelength) - 1);
                        // we delete the bytesdone in bitsread and append the next byte(s)
                        bytesdone = (bitsdone + codelength) / 8;
                        bitsdone = (bitsdone + codelength) % 8;
                        while (bytesdone > 0) {
                            bytesdone--;
                            bitsread = (bitsread >> 8);
                            if (size > 0) {
                                size--; bytesread++; bitsread += (is.read() << 16);
                            }
                            else {
                                size = is.read();
                                if (size > 0) {
                                    size--; bytesread++; bitsread += (is.read() << 16);
                                }
                            }
                        }
                        // we package all the bits that are done into bytes and write them to the stream
                        bitstowrite += (code << (bitsleft - codelength + 1));
                        bitsleft -= codelength;
                        while (bitsleft < 16) {
                            streamBytes.write(bitstowrite >> 16);
                            byteswritten++;
                            bitstowrite = (bitstowrite & 0xFFFF) << 8;
                            bitsleft += 8;
                        }
                        if (code == 256) {
                            codelength = 9;
                            tablelength = 257;
                        }
                        if (code == 257) {
                            break;
                        }
                        if (tablelength == (1 << codelength)) {
                            codelength++;
                        }
                    }
                    if (bytesread - byteswritten > 2) {
                        throw new BadPdfFormatException(errorID + " is not a supported GIF-file (unexpected end of data block).");
                    }
                    break;
                default:
                    throw new BadPdfFormatException(errorID + " is an unknown Image format.");
            }
            put(PdfName.LENGTH, new PdfNumber(streamBytes.size()));
        }
        catch(IOException ioe) {
            throw new BadPdfFormatException(ioe.getMessage());
        }
        finally {
            if (is != null) {
                try{
                    is.close();
                }
                catch (Exception ee) {
                    // empty on purpose
                }
            }
        }
    }
    
    /**
     * Returns the <CODE>PdfName</CODE> of the image.
     *
     * @return		the name
     */
    
    public PdfName name() {
        return name;
    }
    
    static void transferBytes(InputStream in, OutputStream out, int len) throws IOException {
        byte buffer[] = new byte[TRANSFERSIZE];
        if (len < 0)
            len = 0x7ffffff;
        int size;
        while (len != 0) {
            size = in.read(buffer, 0, Math.min(len, TRANSFERSIZE));
            if (size < 0)
                return;
            out.write(buffer, 0, size);
            len -= size;
        }
    }
}