Raster, using a specified matrix.
*
* The width of the matrix must be equal to the number of bands in the
* source Raster, optionally plus one. If there is one more
* column in the matrix than the number of bands, there is an implied 1 at the
* end of the vector of band samples representing a pixel. The height
* of the matrix must be equal to the number of bands in the destination.
*
* For example, a 3-banded Raster might have the following
* transformation applied to each pixel in order to invert the second band of
* the Raster.
*
* [ 1.0 0.0 0.0 0.0 ] [ b1 ] * [ 0.0 -1.0 0.0 255.0 ] x [ b2 ] * [ 0.0 0.0 1.0 0.0 ] [ b3 ] * [ 1 ] ** *
* Note that the source and destination can be the same object.
*/
public class BandCombineOp implements RasterOp {
float[][] matrix;
int nrows = 0;
int ncols = 0;
RenderingHints hints;
/**
* Constructs a BandCombineOp with the specified matrix.
* The width of the matrix must be equal to the number of bands in
* the source Raster, optionally plus one. If there is one
* more column in the matrix than the number of bands, there is an implied
* 1 at the end of the vector of band samples representing a pixel. The
* height of the matrix must be equal to the number of bands in the
* destination.
*
* The first subscript is the row index and the second
* is the column index. This operation uses none of the currently
* defined rendering hints; the RenderingHints argument can be
* null.
*
* @param matrix The matrix to use for the band combine operation.
* @param hints The RenderingHints object for this operation.
* Not currently used so it can be null.
*/
public BandCombineOp (float[][] matrix, RenderingHints hints) {
nrows = matrix.length;
ncols = matrix[0].length;
this.matrix = new float[nrows][];
for (int i=0; i < nrows; i++) {
/* Arrays.copyOf is forgiving of the source array being
* too short, but it is also faster than other cloning
* methods, so we provide our own protection for short
* matrix rows.
*/
if (ncols > matrix[i].length) {
throw new IndexOutOfBoundsException("row "+i+" too short");
}
this.matrix[i] = Arrays.copyOf(matrix[i], ncols);
}
this.hints = hints;
}
/**
* Returns a copy of the linear combination matrix.
*
* @return The matrix associated with this band combine operation.
*/
public final float[][] getMatrix() {
float[][] ret = new float[nrows][];
for (int i = 0; i < nrows; i++) {
ret[i] = Arrays.copyOf(matrix[i], ncols);
}
return ret;
}
/**
* Transforms the Raster using the matrix specified in the
* constructor. An IllegalArgumentException may be thrown if
* the number of bands in the source or destination is incompatible with
* the matrix. See the class comments for more details.
*
* If the destination is null, it will be created with a number of bands
* equalling the number of rows in the matrix. No exception is thrown
* if the operation causes a data overflow.
*
* @param src The Raster to be filtered.
* @param dst The Raster in which to store the results
* of the filter operation.
*
* @return The filtered Raster.
*
* @throws IllegalArgumentException If the number of bands in the
* source or destination is incompatible with the matrix.
*/
public WritableRaster filter(Raster src, WritableRaster dst) {
int nBands = src.getNumBands();
if (ncols != nBands && ncols != (nBands+1)) {
throw new IllegalArgumentException("Number of columns in the "+
"matrix ("+ncols+
") must be equal to the number"+
" of bands ([+1]) in src ("+
nBands+").");
}
if (dst == null) {
dst = createCompatibleDestRaster(src);
}
else if (nrows != dst.getNumBands()) {
throw new IllegalArgumentException("Number of rows in the "+
"matrix ("+nrows+
") must be equal to the number"+
" of bands ([+1]) in dst ("+
nBands+").");
}
if (ImagingLib.filter(this, src, dst) != null) {
return dst;
}
int[] pixel = null;
int[] dstPixel = new int[dst.getNumBands()];
float accum;
int sminX = src.getMinX();
int sY = src.getMinY();
int dminX = dst.getMinX();
int dY = dst.getMinY();
int sX;
int dX;
if (ncols == nBands) {
for (int y=0; y < src.getHeight(); y++, sY++, dY++) {
dX = dminX;
sX = sminX;
for (int x=0; x < src.getWidth(); x++, sX++, dX++) {
pixel = src.getPixel(sX, sY, pixel);
for (int r=0; r < nrows; r++) {
accum = 0.f;
for (int c=0; c < ncols; c++) {
accum += matrix[r][c]*pixel[c];
}
dstPixel[r] = (int) accum;
}
dst.setPixel(dX, dY, dstPixel);
}
}
}
else {
// Need to add constant
for (int y=0; y < src.getHeight(); y++, sY++, dY++) {
dX = dminX;
sX = sminX;
for (int x=0; x < src.getWidth(); x++, sX++, dX++) {
pixel = src.getPixel(sX, sY, pixel);
for (int r=0; r < nrows; r++) {
accum = 0.f;
for (int c=0; c < nBands; c++) {
accum += matrix[r][c]*pixel[c];
}
dstPixel[r] = (int) (accum+matrix[r][nBands]);
}
dst.setPixel(dX, dY, dstPixel);
}
}
}
return dst;
}
/**
* Returns the bounding box of the transformed destination. Since
* this is not a geometric operation, the bounding box is the same for
* the source and destination.
* An IllegalArgumentException may be thrown if the number of
* bands in the source is incompatible with the matrix. See
* the class comments for more details.
*
* @param src The Raster to be filtered.
*
* @return The Rectangle2D representing the destination
* image's bounding box.
*
* @throws IllegalArgumentException If the number of bands in the source
* is incompatible with the matrix.
*/
public final Rectangle2D getBounds2D (Raster src) {
return src.getBounds();
}
/**
* Creates a zeroed destination Raster with the correct size
* and number of bands.
* An IllegalArgumentException may be thrown if the number of
* bands in the source is incompatible with the matrix. See
* the class comments for more details.
*
* @param src The Raster to be filtered.
*
* @return The zeroed destination Raster.
*/
public WritableRaster createCompatibleDestRaster (Raster src) {
int nBands = src.getNumBands();
if ((ncols != nBands) && (ncols != (nBands+1))) {
throw new IllegalArgumentException("Number of columns in the "+
"matrix ("+ncols+
") must be equal to the number"+
" of bands ([+1]) in src ("+
nBands+").");
}
if (src.getNumBands() == nrows) {
return src.createCompatibleWritableRaster();
}
else {
throw new IllegalArgumentException("Don't know how to create a "+
" compatible Raster with "+
nrows+" bands.");
}
}
/**
* Returns the location of the corresponding destination point given a
* point in the source Raster. If dstPt is
* specified, it is used to hold the return value.
* Since this is not a geometric operation, the point returned
* is the same as the specified srcPt.
*
* @param srcPt The Point2D that represents the point in
* the source Raster
* @param dstPt The Point2D in which to store the result.
*
* @return The Point2D in the destination image that
* corresponds to the specified point in the source image.
*/
public final Point2D getPoint2D (Point2D srcPt, Point2D dstPt) {
if (dstPt == null) {
dstPt = new Point2D.Float();
}
dstPt.setLocation(srcPt.getX(), srcPt.getY());
return dstPt;
}
/**
* Returns the rendering hints for this operation.
*
* @return The RenderingHints object associated with this
* operation. Returns null if no hints have been set.
*/
public final RenderingHints getRenderingHints() {
return hints;
}
}