bmpimage.java

处理PDF

            }
        } else {
            count = -padding;
            for (int i=0; i<height; i++) {
                count += padding;
                for (int j=0; j<width; j++) {
                    bdata[l + 2] = values[count++];
                    bdata[l + 1] = values[count++];
                    bdata[l] = values[count++];
                    l += 3;
                }
            }
        }
    }
    
    private int findMask(int mask) {
        int k = 0;
        for (; k < 32; ++k) {
            if ((mask & 1) == 1)
                break;
            mask >>>= 1;
        }
        return mask;
    }
    
    private int findShift(int mask) {
        int k = 0;
        for (; k < 32; ++k) {
            if ((mask & 1) == 1)
                break;
            mask >>>= 1;
        }
        return k;
    }
    
    private Image read1632Bit(boolean is32) throws IOException, BadElementException {
        
        int red_mask = findMask(redMask);
        int red_shift = findShift(redMask);
        int red_factor = red_mask + 1;
        int green_mask = findMask(greenMask);
        int green_shift = findShift(greenMask);
        int green_factor = green_mask + 1;
        int blue_mask = findMask(blueMask);
        int blue_shift = findShift(blueMask);
        int blue_factor = blue_mask + 1;
        byte bdata[] = new byte[width * height * 3];
        // Padding bytes at the end of each scanline
        int padding = 0;
        
        if (!is32) {
        // width * bitsPerPixel should be divisible by 32
            int bitsPerScanline = width * 16;
            if ( bitsPerScanline%32 != 0) {
                padding = (bitsPerScanline/32 + 1)*32 - bitsPerScanline;
                padding = (int)Math.ceil(padding/8.0);
            }
        }
        
        int imSize = (int)imageSize;
        if (imSize == 0) {
            imSize = (int)(bitmapFileSize - bitmapOffset);
        }
        
        int l=0;
        int v;
        if (isBottomUp) {
            for (int i=height - 1; i >= 0; --i) {
                l = width * 3 * i;
                for (int j=0; j<width; j++) {
                    if (is32)
                        v = (int)readDWord(inputStream);
                    else
                        v = readWord(inputStream);
                    bdata[l++] = (byte)(((v >>> red_shift) & red_mask) * 256 / red_factor);
                    bdata[l++] = (byte)(((v >>> green_shift) & green_mask) * 256 / green_factor);
                    bdata[l++] = (byte)(((v >>> blue_shift) & blue_mask) * 256 / blue_factor);
                }
                for (int m=0; m<padding; m++) {
                    inputStream.read();
                }
            }
        } else {
            for (int i=0; i<height; i++) {
                for (int j=0; j<width; j++) {
                    if (is32)
                        v = (int)readDWord(inputStream);
                    else
                        v = readWord(inputStream);
                    bdata[l++] = (byte)(((v >>> red_shift) & red_mask) * 256 / red_factor);
                    bdata[l++] = (byte)(((v >>> green_shift) & green_mask) * 256 / green_factor);
                    bdata[l++] = (byte)(((v >>> blue_shift) & blue_mask) * 256 / blue_factor);
                }
                for (int m=0; m<padding; m++) {
                    inputStream.read();
                }
            }
        }
        return new ImgRaw(width, height, 3, 8, bdata);
    }
    
    private Image readRLE8() throws IOException, BadElementException {
        
        // If imageSize field is not provided, calculate it.
        int imSize = (int)imageSize;
        if (imSize == 0) {
            imSize = (int)(bitmapFileSize - bitmapOffset);
        }
        
        // Read till we have the whole image
        byte values[] = new byte[imSize];
        int bytesRead = 0;
        while (bytesRead < imSize) {
            bytesRead += inputStream.read(values, bytesRead,
            imSize - bytesRead);
        }
        
        // Since data is compressed, decompress it
        byte val[] = decodeRLE(true, values);
        
        // Uncompressed data does not have any padding
        imSize = width * height;
        
        if (isBottomUp) {
            
            // Convert the bottom up image to a top down format by copying
            // one scanline from the bottom to the top at a time.
            // int bytesPerScanline = (int)Math.ceil((double)width/8.0);
            byte temp[] = new byte[val.length];
            int bytesPerScanline = width;
            for (int i=0; i<height; i++) {
                System.arraycopy(val,
                imSize - (i+1)*(bytesPerScanline),
                temp,
                i*bytesPerScanline, bytesPerScanline);
            }
            val = temp;
        }
        return indexedModel(val, 8, 4);
    }
    
    private Image readRLE4() throws IOException, BadElementException {
        
        // If imageSize field is not specified, calculate it.
        int imSize = (int)imageSize;
        if (imSize == 0) {
            imSize = (int)(bitmapFileSize - bitmapOffset);
        }
        
        // Read till we have the whole image
        byte values[] = new byte[imSize];
        int bytesRead = 0;
        while (bytesRead < imSize) {
            bytesRead += inputStream.read(values, bytesRead,
            imSize - bytesRead);
        }
        
        // Decompress the RLE4 compressed data.
        byte val[] = decodeRLE(false, values);
        
        // Invert it as it is bottom up format.
        if (isBottomUp) {
            
            byte inverted[] = val;
            val = new byte[width * height];
            int l = 0, index, lineEnd;
            
            for (int i = height-1; i >= 0; i--) {
                index = i * width;
                lineEnd = l + width;
                while(l != lineEnd) {
                    val[l++] = inverted[index++];
                }
            }
        }
        int stride = ((width + 1) / 2);
        byte bdata[] = new byte[stride * height];
        int ptr = 0;
        int sh = 0;
        for (int h = 0; h < height; ++h) {
            for (int w = 0; w < width; ++w) {
                if ((w & 1) == 0)
                    bdata[sh + w / 2] = (byte)(val[ptr++] << 4);
                else
                    bdata[sh + w / 2] |= (byte)(val[ptr++] & 0x0f);
            }
            sh += stride;
        }
        return indexedModel(bdata, 4, 4);
    }
    
    private byte[] decodeRLE(boolean is8, byte values[]) {
        byte val[] = new byte[width * height];
        try {
            int ptr = 0;
            int x = 0;
            int q = 0;
            for (int y = 0; y < height && ptr < values.length;) {
                int count = values[ptr++] & 0xff;
                if (count != 0) {
                    // encoded mode
                    int bt = values[ptr++] & 0xff;
                    if (is8) {
                        for (int i = count; i != 0; --i) {
                            val[q++] = (byte)bt;
                        }
                    }
                    else {
                        for (int i = 0; i < count; ++i) {
                            val[q++] = (byte)((i & 1) == 1 ? (bt & 0x0f) : ((bt >>> 4) & 0x0f));
                        }
                    }
                    x += count;
                }
                else {
                    // escape mode
                    count = values[ptr++] & 0xff;
                    if (count == 1)
                        break;
                    switch (count) {
                        case 0:
                            x = 0;
                            ++y;
                            q = y * width;
                            break;
                        case 2:
                            // delta mode
                            x += values[ptr++] & 0xff;
                            y += values[ptr++] & 0xff;
                            q = y * width + x;
                            break;
                        default:
                            // absolute mode
                            if (is8) {
                                for (int i = count; i != 0; --i)
                                    val[q++] = (byte)(values[ptr++] & 0xff);
                            }
                            else {
                                int bt = 0;
                                for (int i = 0; i < count; ++i) {
                                    if ((i & 1) == 0)
                                        bt = values[ptr++] & 0xff;
                                    val[q++] = (byte)((i & 1) == 1 ? (bt & 0x0f) : ((bt >>> 4) & 0x0f));
                                }
                            }
                            x += count;
                            // read pad byte
                            if (is8) {
                                if ((count & 1) == 1)
                                    ++ptr;
                            }
                            else {
                                if ((count & 3) == 1 || (count & 3) == 2)
                                    ++ptr;
                            }
                            break;
                    }
                }
            }
        }
        catch (RuntimeException e) {
            //empty on purpose
        }
        
        return val;
    }
    
    // Windows defined data type reading methods - everything is little endian
    
    // Unsigned 8 bits
    private int readUnsignedByte(InputStream stream) throws IOException {
        return (stream.read() & 0xff);
    }
    
    // Unsigned 2 bytes
    private int readUnsignedShort(InputStream stream) throws IOException {
        int b1 = readUnsignedByte(stream);
        int b2 = readUnsignedByte(stream);
        return ((b2 << 8) | b1) & 0xffff;
    }
    
    // Signed 16 bits
    private int readShort(InputStream stream) throws IOException {
        int b1 = readUnsignedByte(stream);
        int b2 = readUnsignedByte(stream);
        return (b2 << 8) | b1;
    }
    
    // Unsigned 16 bits
    private int readWord(InputStream stream) throws IOException {
        return readUnsignedShort(stream);
    }
    
    // Unsigned 4 bytes
    private long readUnsignedInt(InputStream stream) throws IOException {
        int b1 = readUnsignedByte(stream);
        int b2 = readUnsignedByte(stream);
        int b3 = readUnsignedByte(stream);
        int b4 = readUnsignedByte(stream);
        long l = (b4 << 24) | (b3 << 16) | (b2 << 8) | b1;
        return l & 0xffffffff;
    }
    
    // Signed 4 bytes
    private int readInt(InputStream stream) throws IOException {
        int b1 = readUnsignedByte(stream);
        int b2 = readUnsignedByte(stream);
        int b3 = readUnsignedByte(stream);
        int b4 = readUnsignedByte(stream);
        return (b4 << 24) | (b3 << 16) | (b2 << 8) | b1;
    }
    
    // Unsigned 4 bytes
    private long readDWord(InputStream stream) throws IOException {
        return readUnsignedInt(stream);
    }
    
    // 32 bit signed value
    private int readLong(InputStream stream) throws IOException {
        return readInt(stream);
    }
}