Constructor Detail

• StandardImageTiler

  public StandardImageTiler(RandomAccess f,
                            long fileOffset,
                            int[] dims,
                            java.lang.Class<?> base)

  Create a tiler.

  Parameters:

  f - The random access device from which image data may be read. This may be null if the tile information is available from memory.

  fileOffset - The file offset within the RandomAccess device at which the data begins.

  dims - The actual dimensions of the image.

  base - The base class (should be a primitive type) of the image.

Method Detail

• getOffset

  public static int getOffset(int[] dims,
                              int[] pos)

  Parameters:

  dims - The dimensions of the array.

  pos - The index requested.

  Returns:

  the offset of a given position.

• incrementPosition

  protected static boolean incrementPosition(int[] start,
                                             int[] current,
                                             int[] lengths)

  Increment the offset within the position array. Note that we never look at the last index since we copy data a block at a time and not byte by byte.

  Parameters:

  start - The starting corner values.

  current - The current offsets.

  lengths - The desired dimensions of the subset.

  Returns:

  true if the current array was changed

• fillFileData

  protected void fillFileData(java.lang.Object output,
                              int delta,
                              int outputOffset,
                              int segment)
                       throws java.io.IOException

  File a tile segment from a file.

  Parameters:

  output - The output tile.

  delta - The offset from the beginning of the image in bytes.

  outputOffset - The index into the output array.

  segment - The number of elements to be read for this segment.

  Throws:

  java.io.IOException - if the underlying stream failed

• fillMemData

  protected void fillMemData(java.lang.Object data,
                             int[] posits,
                             int length,
                             java.lang.Object output,
                             int outputOffset,
                             int dim)

  Fill a single segment from memory. This routine is called recursively to handle multi-dimensional arrays. E.g., if data is three-dimensional, this will recurse two levels until we get a call with a single dimensional datum. At that point the appropriate data will be copied into the output.

  Parameters:

  data - The in-memory image data.

  posits - The current position for which data is requested.

  length - The size of the segments.

  output - The output tile.

  outputOffset - The current offset into the output tile.

  dim - The current dimension being

• fillTile

  protected void fillTile(java.lang.Object data,
                          java.lang.Object o,
                          int[] newDims,
                          int[] corners,
                          int[] lengths)
                   throws java.io.IOException

  Fill the subset.

  Parameters:

  data - The memory-resident data image. This may be null if the image is to be read from a file. This should be a multi-dimensional primitive array.

  o - The tile to be filled. This is a simple primitive array.

  newDims - The dimensions of the full image.

  corners - The indices of the corner of the image.

  lengths - The dimensions of the subset.

  Throws:

  java.io.IOException - if the underlying stream failed

• getCompleteImage

  public java.lang.Object getCompleteImage()
                                    throws java.io.IOException

  Read the entire image into a multidimensional array.

  Specified by:

  getCompleteImage in interface ImageTiler

  Throws:

  java.io.IOException - if the underlying stream failed

• getMemoryImage

  protected abstract java.lang.Object getMemoryImage()

  See if we can get the image data from memory. This may be overridden by other classes, notably in nom.tam.fits.ImageData.

  Returns:

  the image data

• getTile

  public java.lang.Object getTile(int[] corners,
                                  int[] lengths)
                           throws java.io.IOException

  Get a subset of the image. An image tile is returned as a one-dimensional array although the image will normally be multi-dimensional.

  Specified by:

  getTile in interface ImageTiler

  Parameters:

  corners - The starting corner (using 0 as the start) for the image.

  lengths - The length requested in each dimension.

  Throws:

  java.io.IOException - if the underlying stream failed

• getTile

  public void getTile(java.lang.Object outArray,
                      int[] corners,
                      int[] lengths)
               throws java.io.IOException

  Get a tile, filling in a prespecified array. This version does not check that the user hase entered a valid set of corner and length arrays. ensure that out matches the length implied by the lengths array.

  Specified by:

  getTile in interface ImageTiler

  Parameters:

  outArray - The output tile array. A one-dimensional array. Data not within the valid limits of the image will be left unchanged. The length of this array should be the product of lengths.

  corners - The corners of the tile.

  lengths - The dimensions of the tile.

  Throws:

  java.io.IOException - if the underlying stream failed