truetypefont.java

iText是一个能够快速产生PDF文件的java类库。iText的java类对于那些要产生包含文本

    
    private void readBbox() throws DocumentException, IOException {
        int tableLocation[];
        tableLocation = (int[])tables.get("head");
        if (tableLocation == null)
            throw new DocumentException("Table 'head' does not exist in " + fileName + style);
        rf.seek(tableLocation[0] + TrueTypeFontSubSet.HEAD_LOCA_FORMAT_OFFSET);
        boolean locaShortTable = (rf.readUnsignedShort() == 0);
        tableLocation = (int[])tables.get("loca");
        if (tableLocation == null)
            return;
        rf.seek(tableLocation[0]);
        int locaTable[];
        if (locaShortTable) {
            int entries = tableLocation[1] / 2;
            locaTable = new int[entries];
            for (int k = 0; k < entries; ++k)
                locaTable[k] = rf.readUnsignedShort() * 2;
        }
        else {
            int entries = tableLocation[1] / 4;
            locaTable = new int[entries];
            for (int k = 0; k < entries; ++k)
                locaTable[k] = rf.readInt();
        }
        tableLocation = (int[])tables.get("glyf");
        if (tableLocation == null)
            throw new DocumentException("Table 'glyf' does not exist in " + fileName + style);
        int tableGlyphOffset = tableLocation[0];
        bboxes = new int[locaTable.length - 1][];
        for (int glyph = 0; glyph < locaTable.length - 1; ++glyph) {
            int start = locaTable[glyph];
            if (start != locaTable[glyph + 1]) {
                rf.seek(tableGlyphOffset + start + 2);
                bboxes[glyph] = new int[]{
                    (rf.readShort() * 1000) / head.unitsPerEm,
                    (rf.readShort() * 1000) / head.unitsPerEm,
                    (rf.readShort() * 1000) / head.unitsPerEm,
                    (rf.readShort() * 1000) / head.unitsPerEm};
            }
        }
    }
    
    /** Reads the several maps from the table 'cmap'. The maps of interest are 1.0 for symbolic
     *  fonts and 3.1 for all others. A symbolic font is defined as having the map 3.0.
     * @throws DocumentException the font is invalid
     * @throws IOException the font file could not be read
     */
    void readCMaps() throws DocumentException, IOException {
        int table_location[];
        table_location = (int[])tables.get("cmap");
        if (table_location == null)
            throw new DocumentException("Table 'cmap' does not exist in " + fileName + style);
        rf.seek(table_location[0]);
        rf.skipBytes(2);
        int num_tables = rf.readUnsignedShort();
        fontSpecific = false;
        int map10 = 0;
        int map31 = 0;
        int map30 = 0;
        for (int k = 0; k < num_tables; ++k) {
            int platId = rf.readUnsignedShort();
            int platSpecId = rf.readUnsignedShort();
            int offset = rf.readInt();
            if (platId == 3 && platSpecId == 0) {
                fontSpecific = true;
                map30 = offset;
            }
            else if (platId == 3 && platSpecId == 1) {
                map31 = offset;
            }
            if (platId == 1 && platSpecId == 0) {
                map10 = offset;
            }
        }
        if (map10 > 0) {
            rf.seek(table_location[0] + map10);
            int format = rf.readUnsignedShort();
            switch (format) {
                case 0:
                    cmap10 = readFormat0();
                    break;
                case 4:
                    cmap10 = readFormat4();
                    break;
                case 6:
                    cmap10 = readFormat6();
                    break;
            }
        }
        if (map31 > 0) {
            rf.seek(table_location[0] + map31);
            int format = rf.readUnsignedShort();
            if (format == 4) {
                cmap31 = readFormat4();
            }
        }
        if (map30 > 0) {
            rf.seek(table_location[0] + map30);
            int format = rf.readUnsignedShort();
            if (format == 4) {
                cmap10 = readFormat4();
            }
        }
    }
    
    /** The information in the maps of the table 'cmap' is coded in several formats.
     *  Format 0 is the Apple standard character to glyph index mapping table.
     * @return a <CODE>HashMap</CODE> representing this map
     * @throws IOException the font file could not be read
     */
    HashMap readFormat0() throws IOException {
        HashMap h = new HashMap();
        rf.skipBytes(4);
        for (int k = 0; k < 256; ++k) {
            int r[] = new int[2];
            r[0] = rf.readUnsignedByte();
            r[1] = getGlyphWidth(r[0]);
            h.put(new Integer(k), r);
        }
        return h;
    }
    
    /** The information in the maps of the table 'cmap' is coded in several formats.
     *  Format 4 is the Microsoft standard character to glyph index mapping table.
     * @return a <CODE>HashMap</CODE> representing this map
     * @throws IOException the font file could not be read
     */
    HashMap readFormat4() throws IOException {
        HashMap h = new HashMap();
        int table_lenght = rf.readUnsignedShort();
        rf.skipBytes(2);
        int segCount = rf.readUnsignedShort() / 2;
        rf.skipBytes(6);
        int endCount[] = new int[segCount];
        for (int k = 0; k < segCount; ++k) {
            endCount[k] = rf.readUnsignedShort();
        }
        rf.skipBytes(2);
        int startCount[] = new int[segCount];
        for (int k = 0; k < segCount; ++k) {
            startCount[k] = rf.readUnsignedShort();
        }
        int idDelta[] = new int[segCount];
        for (int k = 0; k < segCount; ++k) {
            idDelta[k] = rf.readUnsignedShort();
        }
        int idRO[] = new int[segCount];
        for (int k = 0; k < segCount; ++k) {
            idRO[k] = rf.readUnsignedShort();
        }
        int glyphId[] = new int[table_lenght / 2 - 8 - segCount * 4];
        for (int k = 0; k < glyphId.length; ++k) {
            glyphId[k] = rf.readUnsignedShort();
        }
        for (int k = 0; k < segCount; ++k) {
            int glyph;
            for (int j = startCount[k]; j <= endCount[k] && j != 0xFFFF; ++j) {
                if (idRO[k] == 0) {
                    glyph = (j + idDelta[k]) & 0xFFFF;
                }
                else {
                    int idx = k + idRO[k] / 2 - segCount + j - startCount[k];
                    if (idx >= glyphId.length)
                        continue;
                    glyph = (glyphId[idx] + idDelta[k]) & 0xFFFF;
                }
                int r[] = new int[2];
                r[0] = glyph;
                r[1] = getGlyphWidth(r[0]);
                h.put(new Integer(fontSpecific ? ((j & 0xff00) == 0xf000 ? j & 0xff : j) : j), r);
            }
        }
        return h;
    }
    
    /** The information in the maps of the table 'cmap' is coded in several formats.
     *  Format 6 is a trimmed table mapping. It is similar to format 0 but can have
     *  less than 256 entries.
     * @return a <CODE>HashMap</CODE> representing this map
     * @throws IOException the font file could not be read
     */
    HashMap readFormat6() throws IOException {
        HashMap h = new HashMap();
        rf.skipBytes(4);
        int start_code = rf.readUnsignedShort();
        int code_count = rf.readUnsignedShort();
        for (int k = 0; k < code_count; ++k) {
            int r[] = new int[2];
            r[0] = rf.readUnsignedShort();
            r[1] = getGlyphWidth(r[0]);
            h.put(new Integer(k + start_code), r);
        }
        return h;
    }
    
    /** Reads the kerning information from the 'kern' table.
     * @throws IOException the font file could not be read
     */
    void readKerning() throws IOException {
        int table_location[];
        table_location = (int[])tables.get("kern");
        if (table_location == null)
            return;
        rf.seek(table_location[0] + 2);
        int nTables = rf.readUnsignedShort();
        int checkpoint = table_location[0] + 4;
        int length = 0;
        for (int k = 0; k < nTables; ++k) {
            checkpoint += length;
            rf.seek(checkpoint);
            rf.skipBytes(2);
            length = rf.readUnsignedShort();
            int coverage = rf.readUnsignedShort();
            if ((coverage & 0xfff7) == 0x0001) {
                int nPairs = rf.readUnsignedShort();
                rf.skipBytes(6);
                for (int j = 0; j < nPairs; ++j) {
                    int pair = rf.readInt();
                    int value = ((int)rf.readShort() * 1000) / head.unitsPerEm;
                    kerning.put(pair, value);
                }
            }
        }
    }
    
    /** Gets the kerning between two Unicode chars.
     * @param char1 the first char
     * @param char2 the second char
     * @return the kerning to be applied
     */
    public int getKerning(char char1, char char2) {
        int metrics[] = getMetricsTT(char1);
        if (metrics == null)
            return 0;
        int c1 = metrics[0];
        metrics = getMetricsTT(char2);
        if (metrics == null)
            return 0;
        int c2 = metrics[0];
        return kerning.get((c1 << 16) + c2);
    }
    
    /** Gets the width from the font according to the unicode char <CODE>c</CODE>.
     * If the <CODE>name</CODE> is null it's a symbolic font.
     * @param c the unicode char
     * @param name the glyph name
     * @return the width of the char
     */
    int getRawWidth(int c, String name) {
        HashMap map = null;
        if (name == null || cmap31 == null)
            map = cmap10;
        else
            map = cmap31;
        if (map == null)
            return 0;
        int metric[] = (int[])map.get(new Integer(c));
        if (metric == null)
            return 0;
        return metric[1];
    }
    
    /** Generates the font descriptor for this font.
     * @return the PdfDictionary containing the font descriptor or <CODE>null</CODE>
     * @param subsetPrefix the subset prefix
     * @param fontStream the indirect reference to a PdfStream containing the font or <CODE>null</CODE>
     * @throws DocumentException if there is an error
     */
    protected PdfDictionary getFontDescriptor(PdfIndirectReference fontStream, String subsetPrefix) {
        PdfDictionary dic = new PdfDictionary(PdfName.FONTDESCRIPTOR);
        dic.put(PdfName.ASCENT, new PdfNumber((int)os_2.sTypoAscender * 1000 / head.unitsPerEm));
        dic.put(PdfName.CAPHEIGHT, new PdfNumber((int)os_2.sCapHeight * 1000 / head.unitsPerEm));
        dic.put(PdfName.DESCENT, new PdfNumber((int)os_2.sTypoDescender * 1000 / head.unitsPerEm));
        dic.put(PdfName.FONTBBOX, new PdfRectangle(
        (int)head.xMin * 1000 / head.unitsPerEm,
        (int)head.yMin * 1000 / head.unitsPerEm,
        (int)head.xMax * 1000 / head.unitsPerEm,
        (int)head.yMax * 1000 / head.unitsPerEm));
        if (cff) {
            if (encoding.startsWith("Identity-"))
                dic.put(PdfName.FONTNAME, new PdfName(subsetPrefix + fontName+"-"+encoding));
            else
                dic.put(PdfName.FONTNAME, new PdfName(subsetPrefix + fontName + style));
        }
        else
            dic.put(PdfName.FONTNAME, new PdfName(subsetPrefix + fontName + style));
        dic.put(PdfName.ITALICANGLE, new PdfNumber(italicAngle));
        dic.put(PdfName.STEMV, new PdfNumber(80));
        if (fontStream != null) {
            if (cff)
                dic.put(PdfName.FONTFILE3, fontStream);
            else
                dic.put(PdfName.FONTFILE2, fontStream);
        }
        int flags = 0;
        if (isFixedPitch)
            flags |= 1;
        flags |= fontSpecific ? 4 : 32;
        if ((head.macStyle & 2) != 0)
            flags |= 64;
        if ((head.macStyle & 1) != 0)
            flags |= 262144;
        dic.put(PdfName.FLAGS, new PdfNumber(flags));
        
        return dic;
    }
    
    /** Generates the font dictionary for this font.
     * @return the PdfDictionary containing the font dictionary
     * @param subsetPrefix the subset prefx
     * @param firstChar the first valid character
     * @param lastChar the last valid character
     * @param shortTag a 256 bytes long <CODE>byte</CODE> array where each unused byte is represented by 0
     * @param fontDescriptor the indirect reference to a PdfDictionary containing the font descriptor or <CODE>null</CODE>
     * @throws DocumentException if there is an error
     */
    protected PdfDictionary getFontBaseType(PdfIndirectReference fontDescriptor, String subsetPrefix, int firstChar, int lastChar, byte shortTag[]) {
        PdfDictionary dic = new PdfDictionary(PdfName.FONT);
        if (cff) {
            dic.put(PdfName.SUBTYPE, PdfName.TYPE1);
            dic.put(PdfName.BASEFONT, new PdfName(fontName + style));
        }
        else {
            dic.put(PdfName.SUBTYPE, PdfName.TRUETYPE);
            dic.put(PdfName.BASEFONT, new PdfName(subsetPrefix + fontName + style));
        }
        dic.put(PdfName.BASEFONT, new PdfName(subsetPrefix + fontName + style));
        if (!fontSpecific) {
            for (int k = firstChar; k <= lastChar; ++k) {
                if (!differences[k].equals(notdef)) {
                    firstChar = k;
                    break;
                }
            }
        if (encoding.equals("Cp1252") || encoding.equals("MacRoman"))
                dic.put(PdfName.ENCODING, encoding.equals("Cp1252") ? PdfName.WIN_ANSI_ENCODING : PdfName.MAC_ROMAN_ENCODING);
            else {
                PdfDictionary enc = new PdfDictionary(PdfName.ENCODING);
                PdfArray dif = new PdfArray();
                boolean gap = true;                
                for (int k = firstChar; k <= lastChar; ++k) {
                    if (shortTag[k] != 0) {
                        if (gap) {
                            dif.add(new PdfNumber(k));
                            gap = false;
                        }