FITSDataInt.java
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/*
* Copyright 2002 Association for Universities for Research in Astronomy, Inc.,
* Observatory Control System, Gemini Telescopes Project.
*
* $Id: FITSDataInt.java,v 1.2 2009/02/20 23:10:11 abrighto Exp $
*/
package jsky.image.fits.codec;
import java.awt.image.Raster;
import java.io.IOException;
import java.nio.IntBuffer;
import java.nio.MappedByteBuffer;
import java.awt.image.DataBufferInt;
// -------------------------------------------------------------------
// Note: The FITSData<type> classes can be generated from FITSDataInt
// by typing "make generate" (on UNIX or cygwin systems).
// -------------------------------------------------------------------
/**
* Used for int FITS image data (2D).
*
* @version $Revision: 1.2 $
* @author Allan Brighton
*/
public class FITSDataInt extends FITSData {
// Memory mapped image data, or null if not defined
private IntBuffer _mappedBuffer;
/**
* Constructor
*/
public FITSDataInt(FITSImage fitsImage) {
super(fitsImage);
MappedByteBuffer byteBuffer = fitsImage.getByteBuffer();
if (byteBuffer != null) {
_mappedBuffer = byteBuffer.asIntBuffer();
}
}
/**
* Fill in the given tile with the appropriate image data.
* <p>
* If the memory mapped buffer is not null, the Y axis will be flipped to the normal
* orientation for display, otherwise this needs to be done later in the display widget.
*
* @param tile the tile to fill with data
* @param subsample the increment to use when zooming out using the mapped byte buffer
* @param scaledWidth the total image width in pixels (after prescaling, may be different than the "real" width)
* @param scaledHeight the total image height in pixels (after prescaling, may be different than the "real" height)
*
* @return the tile argument
*/
public Raster getTile(Raster tile, int subsample, int scaledWidth, int scaledHeight) throws IOException {
DataBufferInt dataBuffer = (DataBufferInt) tile.getDataBuffer();
int[] destArray = dataBuffer.getData();
int tw = tile.getWidth(),
th = tile.getHeight(),
x0 = tile.getMinX(),
y0 = tile.getMinY(),
x1 = Math.min(x0 + tw - 1, scaledWidth - 1),
y1 = Math.min(y0 + th - 1, scaledHeight - 1),
xWidth = x1 - x0 + 1;
if (_mappedBuffer != null) {
// flip the Y axis while reading, and save time later on
int tmpY0 = y0;
y0 = scaledHeight - y1 - 1;
y1 = scaledHeight - tmpY0 - 1;
// use memory mapped buffer
if (subsample == 1) {
// normal or zoomed in: include all pixels
for (int j = y1; j >= y0; j--) {
_mappedBuffer.position(j * _width + x0);
_mappedBuffer.get(destArray, (y1 - j) * tw, xWidth);
}
} else {
// zoomed out: skip subsample pixels
for (int j = y1; j >= y0; j--) {
int dst = (y1 - j) * tw;
int src = (j * _width + x0) * subsample;
for (int i = x0; i <= x1; i++) {
destArray[dst++] = _mappedBuffer.get(src);
src += subsample;
}
}
}
} else {
// use image tiler (slower)
fillTile(destArray, x0, y0, tw, th);
}
return tile;
}
/**
* Return a prescaled preview image at "1/factor" of the normal size in the given
* raster tile.
*/
public Raster getPreviewImage(Raster tile, int factor) throws IOException {
if (_mappedBuffer != null) {
// use the memory mapped buffer (faster)
return getTile(tile, factor, tile.getWidth(), tile.getHeight());
}
// use the image tiler (slower)
DataBufferInt dataBuffer = (DataBufferInt) tile.getDataBuffer();
int[] destArray = dataBuffer.getData();
int tw = tile.getWidth(),
th = tile.getHeight(),
w = tw * factor,
h = th * factor,
n,
m = 0;
int[] line = new int[_width];
for (int j = 0; j < h; j += factor) {
n = m++ * tw;
fillTile(line, 0, j, _width, 1);
for (int i = 0; i < w; i += factor) {
destArray[n++] = line[i];
}
}
return tile;
}
}