com.sun.pdfview.RefImage Maven / Gradle / Ivy
/*
* $Id: RefImage.java,v 1.3 2009/01/16 16:26:10 tomoke Exp $
*
* Copyright 2004 Sun Microsystems, Inc., 4150 Network Circle,
* Santa Clara, California 95054, U.S.A. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package com.sun.pdfview;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
/**
* A BufferedImage subclass that holds a strong reference to its graphics
* object. This means that the graphics will never go away as long as
* someone holds a reference to this image, and createGraphics() and
* getGraphics() can be called multiple times safely, and will always return
* the same graphics object.
*/
public class RefImage extends BufferedImage {
/** a strong reference to the graphics object */
private Graphics2D g;
/** Creates a new instance of RefImage */
public RefImage(int width, int height, int type) {
super(width, height, type);
}
/**
* Create a graphics object only if it is currently null, otherwise
* return the existing graphics object.
*/
public Graphics2D createGraphics() {
if (g == null) {
g = super.createGraphics();
}
return g;
}
}