pngimage.java

处理PDF

                filterMethod = is.read();
                interlaceMethod = is.read();
            }
            else if (PLTE.equals(marker)) {
                if (colorType == 3) {
                    PdfArray colorspace = new PdfArray();
                    colorspace.add(PdfName.INDEXED);
                    colorspace.add(getColorspace());
                    colorspace.add(new PdfNumber(len / 3 - 1));
                    ByteBuffer colortable = new ByteBuffer();
                    while ((len--) > 0) {
                        colortable.append_i(is.read());
                    }
                    colorspace.add(new PdfString(colorTable = colortable.toByteArray()));
                    additional.put(PdfName.COLORSPACE, colorspace);
                }
                else {
                    Utilities.skip(is, len);
                }
            }
            else if (pHYs.equals(marker)) {
                int dx = getInt(is);
                int dy = getInt(is);
                int unit = is.read();
                if (unit == 1) {
                    dpiX = (int)(dx * 0.0254f + 0.5f);
                    dpiY = (int)(dy * 0.0254f + 0.5f);
                }
                else {
                    if (dy != 0)
                        XYRatio = (float)dx / (float)dy;
                }
            }
            else if (cHRM.equals(marker)) {
                xW = getInt(is) / 100000f;
                yW = getInt(is) / 100000f;
                xR = getInt(is) / 100000f;
                yR = getInt(is) / 100000f;
                xG = getInt(is) / 100000f;
                yG = getInt(is) / 100000f;
                xB = getInt(is) / 100000f;
                yB = getInt(is) / 100000f;
                hasCHRM = !(Math.abs(xW)<0.0001f||Math.abs(yW)<0.0001f||Math.abs(xR)<0.0001f||Math.abs(yR)<0.0001f||Math.abs(xG)<0.0001f||Math.abs(yG)<0.0001f||Math.abs(xB)<0.0001f||Math.abs(yB)<0.0001f);
            }
            else if (sRGB.equals(marker)) {
                int ri = is.read();
                intent = intents[ri];
                gamma = 2.2f;
                xW = 0.3127f;
                yW = 0.329f;
                xR = 0.64f;
                yR = 0.33f;
                xG = 0.3f;
                yG = 0.6f;
                xB = 0.15f;
                yB = 0.06f;
                hasCHRM = true;
            }
            else if (gAMA.equals(marker)) {
                int gm = getInt(is);
                if (gm != 0) {
                    gamma = 100000f / gm;
                    if (!hasCHRM) {
                        xW = 0.3127f;
                        yW = 0.329f;
                        xR = 0.64f;
                        yR = 0.33f;
                        xG = 0.3f;
                        yG = 0.6f;
                        xB = 0.15f;
                        yB = 0.06f;
                        hasCHRM = true;
                    }
                }
            }
            else if (iCCP.equals(marker)) {
                do {
                    --len;
                } while (is.read() != 0);
                is.read();
                --len;
                byte icccom[] = new byte[len];
                int p = 0;
                while (len > 0) {
                    int r = is.read(icccom, p, len);
                    if (r < 0)
                        throw new IOException("Premature end of file.");
                    p += r;
                    len -= r;
                }
                byte iccp[] = PdfReader.FlateDecode(icccom, true);
                icccom = null;
                try {
                    icc_profile = ICC_Profile.getInstance(iccp);
                }
                catch (RuntimeException e) {
                    icc_profile = null;
                }
            }
            else if (IEND.equals(marker)) {
                break;
            }
            else {
                Utilities.skip(is, len);
            }
            Utilities.skip(is, 4);
        }
    }
    
    PdfObject getColorspace() {
        if (icc_profile != null) {
            if ((colorType & 2) == 0)
                return PdfName.DEVICEGRAY;
            else
                return PdfName.DEVICERGB;
        }
        if (gamma == 1f && !hasCHRM) {
            if ((colorType & 2) == 0)
                return PdfName.DEVICEGRAY;
            else
                return PdfName.DEVICERGB;
        }
        else {
            PdfArray array = new PdfArray();
            PdfDictionary dic = new PdfDictionary();
            if ((colorType & 2) == 0) {
                if (gamma == 1f)
                    return PdfName.DEVICEGRAY;
                array.add(PdfName.CALGRAY);
                dic.put(PdfName.GAMMA, new PdfNumber(gamma));
                dic.put(PdfName.WHITEPOINT, new PdfLiteral("[1 1 1]"));
                array.add(dic);
            }
            else {
                PdfObject wp = new PdfLiteral("[1 1 1]");
                array.add(PdfName.CALRGB);
                if (gamma != 1f) {
                    PdfArray gm = new PdfArray();
                    PdfNumber n = new PdfNumber(gamma);
                    gm.add(n);
                    gm.add(n);
                    gm.add(n);
                    dic.put(PdfName.GAMMA, gm);
                }
                if (hasCHRM) {
                    float z = yW*((xG-xB)*yR-(xR-xB)*yG+(xR-xG)*yB);
                    float YA = yR*((xG-xB)*yW-(xW-xB)*yG+(xW-xG)*yB)/z;
                    float XA = YA*xR/yR;
                    float ZA = YA*((1-xR)/yR-1);
                    float YB = -yG*((xR-xB)*yW-(xW-xB)*yR+(xW-xR)*yB)/z;
                    float XB = YB*xG/yG;
                    float ZB = YB*((1-xG)/yG-1);
                    float YC = yB*((xR-xG)*yW-(xW-xG)*yW+(xW-xR)*yG)/z;
                    float XC = YC*xB/yB;
                    float ZC = YC*((1-xB)/yB-1);
                    float XW = XA+XB+XC;
                    float YW = 1;//YA+YB+YC;
                    float ZW = ZA+ZB+ZC;
                    PdfArray wpa = new PdfArray();
                    wpa.add(new PdfNumber(XW));
                    wpa.add(new PdfNumber(YW));
                    wpa.add(new PdfNumber(ZW));
                    wp = wpa;
                    PdfArray matrix = new PdfArray();
                    matrix.add(new PdfNumber(XA));
                    matrix.add(new PdfNumber(YA));
                    matrix.add(new PdfNumber(ZA));
                    matrix.add(new PdfNumber(XB));
                    matrix.add(new PdfNumber(YB));
                    matrix.add(new PdfNumber(ZB));
                    matrix.add(new PdfNumber(XC));
                    matrix.add(new PdfNumber(YC));
                    matrix.add(new PdfNumber(ZC));
                    dic.put(PdfName.MATRIX, matrix);
                }
                dic.put(PdfName.WHITEPOINT, wp);
                array.add(dic);
            }
            return array;
        }
    }
    
    Image getImage() throws IOException {
        readPng();
        try {
            int pal0 = 0;
            int palIdx = 0;
            palShades = false;
            if (trans != null) {
                for (int k = 0; k < trans.length; ++k) {
                    int n = trans[k] & 0xff;
                    if (n == 0) {
                        ++pal0;
                        palIdx = k;
                    }
                    if (n != 0 && n != 255) {
                        palShades = true;
                        break;
                    }
                }
            }
            if ((colorType & 4) != 0)
                palShades = true;
            genBWMask = (!palShades && (pal0 > 1 || transRedGray >= 0));
            if (!palShades && !genBWMask && pal0 == 1) {
                additional.put(PdfName.MASK, new PdfLiteral("["+palIdx+" "+palIdx+"]"));
            }
            boolean needDecode = (interlaceMethod == 1) || (bitDepth == 16) || ((colorType & 4) != 0) || palShades || genBWMask;
            switch (colorType) {
                case 0:
                    inputBands = 1;
                    break;
                case 2:
                    inputBands = 3;
                    break;
                case 3:
                    inputBands = 1;
                    break;
                case 4:
                    inputBands = 2;
                    break;
                case 6:
                    inputBands = 4;
                    break;
            }
            if (needDecode)
                decodeIdat();
            int components = inputBands;
            if ((colorType & 4) != 0)
                --components;
            int bpc = bitDepth;
            if (bpc == 16)
                bpc = 8;
            Image img;
            if (image != null) {
                if (colorType == 3)
                    img = new ImgRaw(width, height, components, bpc, image);
                else
                    img = Image.getInstance(width, height, components, bpc, image);
            }
            else {
                img = new ImgRaw(width, height, components, bpc, idat.toByteArray());
                img.setDeflated(true);
                PdfDictionary decodeparms = new PdfDictionary();
                decodeparms.put(PdfName.BITSPERCOMPONENT, new PdfNumber(bitDepth));
                decodeparms.put(PdfName.PREDICTOR, new PdfNumber(15));
                decodeparms.put(PdfName.COLUMNS, new PdfNumber(width));
                decodeparms.put(PdfName.COLORS, new PdfNumber((colorType == 3 || (colorType & 2) == 0) ? 1 : 3));
                additional.put(PdfName.DECODEPARMS, decodeparms);
            }
            if (additional.get(PdfName.COLORSPACE) == null)
                additional.put(PdfName.COLORSPACE, getColorspace());
            if (intent != null)
                additional.put(PdfName.INTENT, intent);
            if (additional.size() > 0)
                img.setAdditional(additional);
            if (icc_profile != null)
                img.tagICC(icc_profile);
            if (palShades) {
                Image im2 = Image.getInstance(width, height, 1, 8, smask);
                im2.makeMask();
                img.setImageMask(im2);
            }
            if (genBWMask) {
                Image im2 = Image.getInstance(width, height, 1, 1, smask);
                im2.makeMask();
                img.setImageMask(im2);
            }
            img.setDpi(dpiX, dpiY);
            img.setXYRatio(XYRatio);
            img.setOriginalType(Image.ORIGINAL_PNG);
            return img;
        }
        catch (Exception e) {
            throw new ExceptionConverter(e);
        }
    }
    
    void decodeIdat() {
        int nbitDepth = bitDepth;
        if (nbitDepth == 16)
            nbitDepth = 8;
        int size = -1;
        bytesPerPixel = (bitDepth == 16) ? 2 : 1;
        switch (colorType) {
            case 0:
                size = (nbitDepth * width + 7) / 8 * height;
                break;
            case 2:
                size = width * 3 * height;
                bytesPerPixel *= 3;
                break;
            case 3:
                if (interlaceMethod == 1)
                    size = (nbitDepth * width + 7) / 8 * height;
                bytesPerPixel = 1;
                break;
            case 4:
                size = width * height;
                bytesPerPixel *= 2;
                break;
            case 6:
                size = width * 3 * height;
                bytesPerPixel *= 4;
                break;
        }
        if (size >= 0)
            image = new byte[size];
        if (palShades)
            smask = new byte[width * height];
        else if (genBWMask)
            smask = new byte[(width + 7) / 8 * height];
        ByteArrayInputStream bai = new ByteArrayInputStream(idat.getBuf(), 0, idat.size());
        InputStream infStream = new InflaterInputStream(bai, new Inflater());
        dataStream = new DataInputStream(infStream);
        
        if (interlaceMethod != 1) {
            decodePass(0, 0, 1, 1, width, height);
        }
        else {
            decodePass(0, 0, 8, 8, (width + 7)/8, (height + 7)/8);
            decodePass(4, 0, 8, 8, (width + 3)/8, (height + 7)/8);
            decodePass(0, 4, 4, 8, (width + 3)/4, (height + 3)/8);
            decodePass(2, 0, 4, 4, (width + 1)/4, (height + 3)/4);
            decodePass(0, 2, 2, 4, (width + 1)/2, (height + 1)/4);
            decodePass(1, 0, 2, 2, width/2, (height + 1)/2);
            decodePass(0, 1, 1, 2, width, height/2);
        }
        
    }