/*
* $RCSfile: SourcelessOpImage.java,v $
*
* Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
*
* Use is subject to license terms.
*
* $Revision: 1.1 $
* $Date: 2005/02/11 04:57:21 $
* $State: Exp $
*/
package com.lightcrafts.mediax.jai;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.image.Raster;
import java.awt.image.SampleModel;
import java.awt.image.WritableRaster;
import java.util.Map;
/**
* An abstract base class for image operators that have no image
* sources.
*
* <p> <code>SourcelessOpImage</code> is intended as a convenient superclass
* for <code>OpImage</code>s that have no source image. Some examples are
* constant color images, file readers, protocol-based network readers,
* and mathematically-defined imagery such as fractals.
*
* <p> The <code>computeTile</code> method of this class will call the
* <code>computeRect(PlanarImage[], WritableRaster, Rectangle)</code>
* method of the subclass to perform the computation. The first
* argument will be <code>null</code> as there are no source images.
*
* @see OpImage
*/
public abstract class SourcelessOpImage extends OpImage {
private static ImageLayout layoutHelper(int minX, int minY,
int width, int height,
SampleModel sampleModel,
ImageLayout il) {
ImageLayout layout = (il == null) ?
new ImageLayout() : (ImageLayout)il.clone();
layout.setMinX(minX);
layout.setMinY(minY);
layout.setWidth(width);
layout.setHeight(height);
layout.setSampleModel(sampleModel);
if (!layout.isValid(ImageLayout.TILE_GRID_X_OFFSET_MASK)) {
layout.setTileGridXOffset(layout.getMinX(null));
}
if (!layout.isValid(ImageLayout.TILE_GRID_Y_OFFSET_MASK)) {
layout.setTileGridYOffset(layout.getMinY(null));
}
return layout;
}
/**
* Constructs a <code>SourcelessOpImage</code>. The image bounds
* and <code>SampleModel</code> are set explicitly; other layout
* parameters may be set using the <code>layout</code> parameter.
* The min X, min Y, width, height, and <code>SampleModel</code>
* fields of the <code>layout</code> parameter are ignored.
*
* <p> If <code>sampleModel</code> is <code>null</code>, no
* exceptions will be thrown. However, the caller must be sure to
* set the <code>sampleModel</code> instance variable before
* construction terminates. This feature allows subclasses that
* require external computation such as file loading to defer the
* determination of their <code>SampleModel</code> until after the
* call to <code>super</code>.
*
* <p> Similarly, <code>minX</code>, <code>minY</code>,
* <code>width</code>, and <code>height</code> may be dummy values
* if care is taken to manually set all values that depend on
* them, namely the tile grid offset, tile size, and
* <code>SampleModel</code> width and height.
*
* <p> The tile dimensions, tile grid X and Y offsets, and
* <code>ColorModel</code> of the output will be set in the standard
* way by the <code>OpImage</code> constructor.
*
* @param configuration Configurable attributes of the image including
* configuration variables indexed by
* <code>RenderingHints.Key</code>s and image properties indexed
* by <code>String</code>s or <code>CaselessStringKey</code>s.
* This is simply forwarded to the superclass constructor.
* @param layout an <code>ImageLayout</code> describing the layout.
*
* @since JAI 1.1
*/
public SourcelessOpImage(ImageLayout layout,
Map configuration,
SampleModel sampleModel,
int minX, int minY,
int width, int height) {
super(null,
layoutHelper(minX, minY, width, height, sampleModel, layout),
configuration,
false);
}
/**
* Returns false as SourcelessOpImages often return Rasters
* via computeTile() tile that are internally cached. Some
* subclasses may want to override this method and return true.
*/
public boolean computesUniqueTiles() {
return false;
}
/**
* Computes a tile. Since the operation has no sources,
* there is no need to worry about cobbling.
*
* <p> Subclasses should implement the
* <code>computeRect(PlanarImage[], WritableRaster, Rectangle)</code>
* method to perform the actual computation.
*
* @param tileX The X index of the tile.
* @param tileY The Y index of the tile.
*/
public Raster computeTile(int tileX, int tileY) {
/* Create a new WritableRaster to represent this tile. */
Point org = new Point(tileXToX(tileX), tileYToY(tileY));
WritableRaster dest = createWritableRaster(sampleModel, org);
/* Clip output rectangle to image bounds. */
Rectangle rect = new Rectangle(org.x, org.y,
sampleModel.getWidth(),
sampleModel.getHeight());
Rectangle destRect = rect.intersection(getBounds());
computeRect((PlanarImage[])null, dest, destRect);
return dest;
}
/**
* Throws an IllegalArgumentException since the image has no image
* sources.
*
* @param sourceRect ignored.
* @param sourceIndex ignored.
*
* @throws IllegalArgumentException since the image has no sources.
*/
public Rectangle mapSourceRect(Rectangle sourceRect,
int sourceIndex) {
throw new IllegalArgumentException(
JaiI18N.getString("SourcelessOpImage0"));
}
/**
* Throws an IllegalArgumentException since the image has no image
* sources.
*
* @param destRect ignored.
* @param sourceIndex ignored.
*
* @throws IllegalArgumentException since the image has no sources.
*/
public Rectangle mapDestRect(Rectangle destRect,
int sourceIndex) {
throw new IllegalArgumentException(
JaiI18N.getString("SourcelessOpImage0"));
}
}