How to clone a java.awt.BufferedImage ?

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oliv@linuxmail.org - 11 Mar 2007 16:43 GMT

hi,
I have to use a function that returns a java.awt.BufferedImage :

BufferedImage image=function.method(..);

I want now to clone the "image" instance (different instance but same
information).

// of course it does not work because clone method is not public
        BufferedImage clone=(BufferedImage)image.clone();

What is the fatest way to do that ?

I tried this:
public class MyBufferedImage extends BufferedImage implements
Cloneable {

/* I don't know how to do the constructor ?? */
    MyBufferedImage() {
        super(null,null,true,null);
    }
    public Object clone() throws CloneNotSupportedException
    {
    return super.clone();
    }
}

and I don't know what to do next with this class
thanks

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Tom Hawtin - 11 Mar 2007 19:20 GMT

> I want now to clone the "image" instance (different instance but same
> information).
[quoted text clipped - 3 lines]
>
> What is the fatest way to do that ?

> public class MyBufferedImage extends BufferedImage implements
> Cloneable {

Cloneable is seriously broken. Shallow copying field for field in a
class is almost certainly the wrong thing to do for anything more
complicated than Rectangle.

A close approximation to clone for BufferedImage is:

BufferedImage clone = image.getSubimage(
0, 0, image.getWidth(), image.getHeight()
);

That is a shallow clone - it shares image data with the original. Update
one and the other follows.

I guess you could create a BufferedImage of the same size, getWraster
and then copyData on the original. I really don't know the relative
performance of different ways of using BufferedImage, which probably
depend upon version of Java, graphics card and drivers anyway.

Tom Hawtin

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a24900@googlemail.com - 11 Mar 2007 19:48 GMT

On Mar 11, 4:43 pm, o...@linuxmail.org wrote:

> hi,
> I have to use a function that returns a java.awt.BufferedImage :
[quoted text clipped - 3 lines]
> I want now to clone the "image" instance (different instance but same
> information).

String[] pnames = image.getPropertyNames();
Hashtable<String, Object> cproperties = new Hashtable<String,
Object>();
if(pnames != null) {
for(int i = 0; i < pnames.length; i++) {
cproperties.put(pnames[i], image.getProperty(pnames[i]);
}
}
WritableRaster wr = image.getRaster();
WritableRaster cwr = wr.createCompatibleWritableRaster();
cwr.setRect(wr);
BufferedImage cimage = BufferedImage(
image.getColorModel(), // should be immutable
cwr,
image.isRasterPremultiplied(),
cproperties);

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How to clone a java.awt.BufferedImage ?

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