bmpimagereader.java

java1.6众多例子参考

                                               new int[]{0});
                            finished++;
                        } else if ((lineNo - sourceRegion.y) % scaleY == 0) {
                            int currentLine = (lineNo - sourceRegion.y) / scaleY +
                                destinationRegion.y;
                            int pos = currentLine * lineStride;
                            pos += destinationRegion.x;
                            for (int i = sourceRegion.x;
                                 i < sourceRegion.x + sourceRegion.width;
                                 i += scaleX)
                                bdata[pos++] = val[i];
                            processImageUpdate(bi, 0, currentLine,
                                               destinationRegion.width, 1, 1, 1,
                                               new int[]{0});
                            finished++;
                        }
                    }
                    processImageProgress(100.0F * finished / destinationRegion.height);
                    lineNo += isBottomUp ? -1 : 1;
                    l = 0;

                    if (abortRequested()) {
                        flag = true;
                    }

                    break;

                case 1:
                    // End-of-RLE marker
                    flag = true;
                    break;

                case 2:
                    // delta or vector marker
                    int xoff = values[count++] & 0xff;
                    int yoff = values[count] & 0xff;
                    // Move to the position xoff, yoff down
                    l += xoff + yoff*width;
                    break;

                default:
                    int end = values[count-1] & 0xff;
                    for (int i=0; i<end; i++) {
                        val[l++] = (byte)(values[count++] & 0xff);
                    }

                    // Whenever end pixels can fit into odd number of bytes,
                    // an extra padding byte will be present, so skip that.
                    if ((end & 1) == 1) {
                        count++;
                    }
                }
            } else {
                for (int i=0; i<value; i++) {
                    val[l++] = (byte)(values[count] & 0xff);
                }

                count++;
            }

            // If End-of-RLE data, then exit the while loop
            if (flag) {
                break;
            }
        }
    }

    private void readRLE4(byte[] bdata) throws IOException {

        // If imageSize field is not specified, calculate it.
        int imSize = (int)imageSize;
        if (imSize == 0) {
            imSize = (int)(bitmapFileSize - bitmapOffset);
        }
        
        int padding = 0;
        // If width is not 32 byte aligned, then while uncompressing each
        // scanline will have padding bytes, calculate the amount of padding
        int remainder = width % 4;
        if (remainder != 0) {
            padding = 4 - remainder;
        }
        
        // Read till we have the whole image
        byte[] values = new byte[imSize];
        iis.readFully(values, 0, imSize);

        // Decompress the RLE4 compressed data.
        decodeRLE4(imSize, padding, values, bdata);
    }

    private void decodeRLE4(int imSize,
                            int padding,
                            byte[] values,
                            byte[] bdata) throws IOException {
        byte[] val = new byte[width];
        int count = 0, l = 0;
        int value;
        boolean flag = false;
        int lineNo = isBottomUp ? height - 1 : 0;
        int lineStride =
            ((MultiPixelPackedSampleModel)sampleModel).getScanlineStride();
        int finished = 0;
        
        while (count != imSize) {
            
            value = values[count++] & 0xFF;
            if (value == 0) {
                
                
                // Absolute mode
                switch(values[count++] & 0xFF) {
                    
                case 0:
                    // End-of-scanline marker
                    // End-of-scanline marker
                    if (lineNo >= sourceRegion.y &&
                        lineNo < sourceRegion.y + sourceRegion.height) {
                        if (noTransform) {
                            int pos = lineNo * (width + 1 >> 1);
                            for(int i = 0, j = 0; i < width >> 1; i++)
                                bdata[pos++] =
                                    (byte)((val[j++] << 4) | val[j++]);
                            if ((width & 1) == 1)
                                bdata[pos] |= val[width - 1] << 4;

                            processImageUpdate(bi, 0, lineNo,
                                               destinationRegion.width, 1, 1, 1,
                                               new int[]{0});
                            finished++;
                        } else if ((lineNo - sourceRegion.y) % scaleY == 0) {
                            int currentLine = (lineNo - sourceRegion.y) / scaleY +
                                destinationRegion.y;
                            int pos = currentLine * lineStride;
                            pos += destinationRegion.x >> 1;
                            int shift = (1 - (destinationRegion.x & 1)) << 2;
                            for (int i = sourceRegion.x;
                                 i < sourceRegion.x + sourceRegion.width;
                                 i += scaleX) {
                                bdata[pos] |= val[i] << shift;
                                shift += 4;
                                if (shift == 4) {
                                    pos++;
                                }
                                shift &= 7;
                            }
                            processImageUpdate(bi, 0, currentLine,
                                               destinationRegion.width, 1, 1, 1,
                                               new int[]{0});
                            finished++;
                        }
                    }
                    processImageProgress(100.0F * finished / destinationRegion.height);
                    lineNo += isBottomUp ? -1 : 1;
                    l = 0;

                    if (abortRequested()) {
                        flag = true;
                    }

                    break;

                case 1:
                    // End-of-RLE marker
                    flag = true;
                    break;

                case 2:
                    // delta or vector marker
                    int xoff = values[count++] & 0xFF;
                    int yoff = values[count] & 0xFF;
                    // Move to the position xoff, yoff down
                    l += xoff + yoff*width;
                    break;

                default:
                    int end = values[count-1] & 0xFF;
                    for (int i=0; i<end; i++) {
                        val[l++] = (byte)(((i & 1) == 0) ? (values[count] & 0xf0) >> 4
                                          : (values[count++] & 0x0f));
                    }

                    // When end is odd, the above for loop does not
                    // increment count, so do it now.
                    if ((end & 1) == 1) {
                        count++;
                    }

                    // Whenever end pixels can fit into odd number of bytes,
                    // an extra padding byte will be present, so skip that.
                    if ((((int)Math.ceil(end/2)) & 1) ==1 ) {
                        count++;
                    }
                    break;
                }
            } else {
                // Encoded mode
                int alternate[] = { (values[count] & 0xf0) >> 4,
                                    values[count] & 0x0f };
                for (int i=0; (i < value) && (l < width); i++) {
                    val[l++] = (byte)alternate[i & 1];
                }

                count++;
            }

            // If End-of-RLE data, then exit the while loop
            if (flag) {
                break;
            }
        }
    }

    /** Decodes the jpeg/png image embedded in the bitmap using any jpeg
     *  ImageIO-style plugin.
     *
     * @param bi The destination <code>BufferedImage</code>.
     * @param bmpParam The <code>ImageReadParam</code> for decoding this
     *          BMP image.  The parameters for subregion, band selection and
     *          subsampling are used in decoding the jpeg image.
     */

    private BufferedImage readEmbedded(int type,
                              BufferedImage bi, ImageReadParam bmpParam)
      throws IOException {
        String format;
        switch(type) {
          case BI_JPEG:
              format = "JPEG";
              break;
          case BI_PNG:
              format = "PNG";
              break;
          default:
              throw new
                  IOException("Unexpected compression type: " + type);
        }
        ImageReader reader =
            ImageIO.getImageReadersByFormatName(format).next();
        if (reader == null) {
            throw new RuntimeException(I18N.getString("BMPImageReader4") +
                                       " " + format);
        }
        // prepare input
        byte[] buff = new byte[(int)imageSize];
        iis.read(buff);
        reader.setInput(ImageIO.createImageInputStream(new ByteArrayInputStream(buff)));
        if (bi == null) {
            ImageTypeSpecifier embType = reader.getImageTypes(0).next();
            bi = embType.createBufferedImage(destinationRegion.x +
                                             destinationRegion.width,
                                             destinationRegion.y +
                                             destinationRegion.height);
        }

        reader.addIIOReadProgressListener(new EmbeddedProgressAdapter() {
                public void imageProgress(ImageReader source,
                                          float percentageDone) 
                {            
                    processImageProgress(percentageDone);
                }
            });

        reader.addIIOReadUpdateListener(new IIOReadUpdateListener() {
                public void imageUpdate(ImageReader source, 
                                        BufferedImage theImage, 
                                        int minX, int minY, 
                                        int width, int height, 
                                        int periodX, int periodY, 
                                        int[] bands) 
                {
                    processImageUpdate(theImage, minX, minY, 
                                       width, height, 
                                       periodX, periodY, bands);
                }
                public void passComplete(ImageReader source, 
                                         BufferedImage theImage) 
                {
                    processPassComplete(theImage);
                }
                public void passStarted(ImageReader source, 
                                        BufferedImage theImage, 
                                        int pass, 
                                        int minPass, int maxPass, 
                                        int minX, int minY, 
                                        int periodX, int periodY, 
                                        int[] bands) 
                {
                    processPassStarted(theImage, pass, minPass, maxPass, 
                                       minX, minY, periodX, periodY, 
                                       bands);
                }
                public void thumbnailPassComplete(ImageReader source, 
                                                  BufferedImage thumb) {}
                public void thumbnailPassStarted(ImageReader source, 
                                                 BufferedImage thumb, 
                                                 int pass, 
                                                 int minPass, int maxPass,
                                                 int minX, int minY,
                                                 int periodX, int periodY,
                                                 int[] bands) {}
                public void thumbnailUpdate(ImageReader source, 
                                            BufferedImage theThumbnail,
                                            int minX, int minY, 
                                            int width, int height,
                                            int periodX, int periodY,
                                            int[] bands) {}
            });

        reader.addIIOReadWarningListener(new IIOReadWarningListener() {
                public void warningOccurred(ImageReader source, String warning)
                {
                    processWarningOccurred(warning);
                }
            });
 
        ImageReadParam param = reader.getDefaultReadParam();
        param.setDestination(bi);
        param.setDestinationBands(bmpParam.getDestinationBands());
        param.setDestinationOffset(bmpParam.getDestinationOffset());
        param.setSourceBands(bmpParam.getSourceBands());
        param.setSourceRegion(bmpParam.getSourceRegion());
        param.setSourceSubsampling(bmpParam.getSourceXSubsampling(),
                                   bmpParam.getSourceYSubsampling(),
                                   bmpParam.getSubsamplingXOffset(),
                                   bmpParam.getSubsamplingYOffset());
        reader.read(0, param);
        return bi;
    }

    private class EmbeddedProgressAdapter implements IIOReadProgressListener {
        public void imageComplete(ImageReader src) {}
        public void imageProgress(ImageReader src, float percentageDone) {}
        public void imageStarted(ImageReader src, int imageIndex) {}
        public void thumbnailComplete(ImageReader src) {}
        public void thumbnailProgress(ImageReader src, float percentageDone) {}
        public void thumbnailStarted(ImageReader src, int iIdx, int tIdx) {}
        public void sequenceComplete(ImageReader src) {}
        public void sequenceStarted(ImageReader src, int minIndex) {}
        public void readAborted(ImageReader src) {}
    }
}