/*
* Copyright 1995-2004 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package ae.java.awt.image;
import java.util.Hashtable;
import ae.java.awt.Rectangle;
import ae.java.awt.image.ColorModel;
import ae.java.awt.image.ImageConsumer;
/**
* An ImageFilter class for cropping images.
* This class extends the basic ImageFilter Class to extract a given
* rectangular region of an existing Image and provide a source for a
* new image containing just the extracted region. It is meant to
* be used in conjunction with a FilteredImageSource object to produce
* cropped versions of existing images.
*
* @see FilteredImageSource
* @see ImageFilter
*
* @author Jim Graham
*/
public class CropImageFilter extends ImageFilter {
int cropX;
int cropY;
int cropW;
int cropH;
/**
* Constructs a CropImageFilter that extracts the absolute rectangular
* region of pixels from its source Image as specified by the x, y,
* w, and h parameters.
* @param x the x location of the top of the rectangle to be extracted
* @param y the y location of the top of the rectangle to be extracted
* @param w the width of the rectangle to be extracted
* @param h the height of the rectangle to be extracted
*/
public CropImageFilter(int x, int y, int w, int h) {
cropX = x;
cropY = y;
cropW = w;
cropH = h;
}
/**
* Passes along the properties from the source object after adding a
* property indicating the cropped region.
* This method invokes <code>super.setProperties</code>,
* which might result in additional properties being added.
* <p>
* Note: This method is intended to be called by the
* <code>ImageProducer</code> of the <code>Image</code> whose pixels
* are being filtered. Developers using
* this class to filter pixels from an image should avoid calling
* this method directly since that operation could interfere
* with the filtering operation.
*/
public void setProperties(Hashtable<?,?> props) {
Hashtable<Object,Object> p = (Hashtable<Object,Object>)props.clone();
p.put("croprect", new Rectangle(cropX, cropY, cropW, cropH));
super.setProperties(p);
}
/**
* Override the source image's dimensions and pass the dimensions
* of the rectangular cropped region to the ImageConsumer.
* <p>
* Note: This method is intended to be called by the
* <code>ImageProducer</code> of the <code>Image</code> whose
* pixels are being filtered. Developers using
* this class to filter pixels from an image should avoid calling
* this method directly since that operation could interfere
* with the filtering operation.
* @see ImageConsumer
*/
public void setDimensions(int w, int h) {
consumer.setDimensions(cropW, cropH);
}
/**
* Determine whether the delivered byte pixels intersect the region to
* be extracted and passes through only that subset of pixels that
* appear in the output region.
* <p>
* Note: This method is intended to be called by the
* <code>ImageProducer</code> of the <code>Image</code> whose
* pixels are being filtered. Developers using
* this class to filter pixels from an image should avoid calling
* this method directly since that operation could interfere
* with the filtering operation.
*/
public void setPixels(int x, int y, int w, int h,
ColorModel model, byte pixels[], int off,
int scansize) {
int x1 = x;
if (x1 < cropX) {
x1 = cropX;
}
int x2 = addWithoutOverflow(x, w);
if (x2 > cropX + cropW) {
x2 = cropX + cropW;
}
int y1 = y;
if (y1 < cropY) {
y1 = cropY;
}
int y2 = addWithoutOverflow(y, h);
if (y2 > cropY + cropH) {
y2 = cropY + cropH;
}
if (x1 >= x2 || y1 >= y2) {
return;
}
consumer.setPixels(x1 - cropX, y1 - cropY, (x2 - x1), (y2 - y1),
model, pixels,
off + (y1 - y) * scansize + (x1 - x), scansize);
}
/**
* Determine if the delivered int pixels intersect the region to
* be extracted and pass through only that subset of pixels that
* appear in the output region.
* <p>
* Note: This method is intended to be called by the
* <code>ImageProducer</code> of the <code>Image</code> whose
* pixels are being filtered. Developers using
* this class to filter pixels from an image should avoid calling
* this method directly since that operation could interfere
* with the filtering operation.
*/
public void setPixels(int x, int y, int w, int h,
ColorModel model, int pixels[], int off,
int scansize) {
int x1 = x;
if (x1 < cropX) {
x1 = cropX;
}
int x2 = addWithoutOverflow(x, w);
if (x2 > cropX + cropW) {
x2 = cropX + cropW;
}
int y1 = y;
if (y1 < cropY) {
y1 = cropY;
}
int y2 = addWithoutOverflow(y, h);
if (y2 > cropY + cropH) {
y2 = cropY + cropH;
}
if (x1 >= x2 || y1 >= y2) {
return;
}
consumer.setPixels(x1 - cropX, y1 - cropY, (x2 - x1), (y2 - y1),
model, pixels,
off + (y1 - y) * scansize + (x1 - x), scansize);
}
//check for potential overflow (see bug 4801285)
private int addWithoutOverflow(int x, int w) {
int x2 = x + w;
if ( x > 0 && w > 0 && x2 < 0 ) {
x2 = Integer.MAX_VALUE;
} else if( x < 0 && w < 0 && x2 > 0 ) {
x2 = Integer.MIN_VALUE;
}
return x2;
}
}