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Re: is that possible to include a small PNG file as part of Java class?

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On 6/23/2014 12:02 PM, www wrote:
> Hi:
>
> I have a simple Java class: Abc.java. The method within it needs to access a small PNG file(it's an icon picture). Right now, this picture file("abc.png") is located at nonsrc/icons/abc.png
>
> So this class is a bit pain. Abc.class won't work in the absence of abc.png. When I create an executable JAR, this is pain: always need to remember to include abc.png file inside it.
>
> I am wondering if there is a way that I can "convert" abc.png into some sort of Java code and I can put it in Abc.java. So Abc.class alone can perform the job, without the need of presence of abc.png. Is that possible?
>
> Hope I have explained my intention well.

     Martin Gregorie's response seems to be good advice.  However, if
you simply *must* incorporate your PNG image as a class, you could do
so with a big byte[] array:

	private static final byte[] PNG_BUFFER = {
	    (byte)0x89, 0x50, 0x4E, 0x47, ... };

	public static Image getMyPNG() {
	    return ImageIO.read(new ByteArrayInputStream(PNG_BUFFER));
	}

However, this approach will only work for fairly small images.  The
problem is that Java class files have no way to store an initialized
array: The byte[] array above actually compiles to the equivalent of

	private static final byte[] PNG_BUFFER = new byte[whatever];
	static {
	    PNG_BUFFER[0] = (byte)0x89;
	    PNG_BUFFER[1] = 0x50;
	    PNG_BUFFER[2] = 0x4E;
	    PNG_BUFFER[3] = 0x47;
	    ...
	}

... with about four or so bytecode instructions per array element.
At that rate of bloat, even a modest-sized image risks generating
more code than a Java method can hold.

     You might evade the limits by writing the initialization explicitly
and breaking it up into multiple methods:

	private static final byte[] PNG_BUFFER = new byte[whatever];
	static {
	    firstK();
	    secondK();
	    ...
	}

	private static void firstK() {
	    PNG_BUFFER[0] = (byte)0x89;
	    PNG_BUFFER[1] = 0x50;
	    PNG_BUFFER[2] = 0x4E;
	    PNG_BUFFER[3] = 0x47;
	    ...
	    PNG_BUFFER[1023] = whatever;
	}

	private static void secondK() {
	    PNG_BUFFER[1024] = whatever;
	    ...
	    PNG_BUFFER[2047] = whatever;
	}

	...

IMHO, no sane person would do this.

-- 
Eric Sosman
esosman@comcast-dot-net.invalid

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Thread

is that possible to include a small PNG file as part of Java class? www <xsli2@yahoo.com> - 2014-06-23 09:02 -0700
  Re: is that possible to include a small PNG file as part of Java class? Martin Gregorie <martin@address-in-sig.invalid> - 2014-06-23 16:35 +0000
    Re: is that possible to include a small PNG file as part of Java class? Donkey Hottie <donkey@fredriksson.dy.fi> - 2014-06-24 15:54 +0300
      Re: is that possible to include a small PNG file as part of Java class? Jeff Higgins <jeff@invalid.invalid> - 2014-06-24 10:07 -0400
      Re: is that possible to include a small PNG file as part of Java class? Jeff Higgins <jeff@invalid.invalid> - 2014-06-24 10:49 -0400
      Re: is that possible to include a small PNG file as part of Java class? Roedy Green <see_website@mindprod.com.invalid> - 2014-06-25 01:25 -0700
  Re: is that possible to include a small PNG file as part of Java class? Marcel Müller <news.5.maazl@spamgourmet.org> - 2014-06-23 18:25 +0200
  Re: is that possible to include a small PNG file as part of Java class? Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-06-23 13:03 -0400
    Re: is that possible to include a small PNG file as part of Java class? Wanja Gayk <brixomatic@yahoo.com> - 2014-06-29 11:14 +0200
      Re: is that possible to include a small PNG file as part of Java class? Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-06-29 08:15 -0400
  Re: is that possible to include a small PNG file as part of Java class? markspace <markspace@nospam.nospam> - 2014-06-23 10:39 -0700
  Re: is that possible to include a small PNG file as part of Java class? Jeff Higgins <jeff@invalid.invalid> - 2014-06-23 15:04 -0400
    Re: is that possible to include a small PNG file as part of Java class? Roedy Green <see_website@mindprod.com.invalid> - 2014-06-25 01:34 -0700
  Re: is that possible to include a small PNG file as part of Java class? Joerg Meier <joergmmeier@arcor.de> - 2014-06-23 21:15 +0200
    Re: is that possible to include a small PNG file as part of Java class? Jeff Higgins <jeff@invalid.invalid> - 2014-06-23 15:46 -0400
      Re: is that possible to include a small PNG file as part of Java class? Joerg Meier <joergmmeier@arcor.de> - 2014-06-23 22:08 +0200
        Re: is that possible to include a small PNG file as part of Java class? Jeff Higgins <jeff@invalid.invalid> - 2014-06-23 16:19 -0400
          Re: is that possible to include a small PNG file as part of Java class? Joerg Meier <joergmmeier@arcor.de> - 2014-06-23 22:34 +0200
            Re: is that possible to include a small PNG file as part of Java class? Jeff Higgins <jeff@invalid.invalid> - 2014-06-23 16:43 -0400
              Re: is that possible to include a small PNG file as part of Java class? Joerg Meier <joergmmeier@arcor.de> - 2014-06-24 00:21 +0200
                Re: is that possible to include a small PNG file as part of Java class? Jeff Higgins <jeff@invalid.invalid> - 2014-06-23 21:02 -0400
                Re: is that possible to include a small PNG file as part of Java class? Jeff Higgins <jeff@invalid.invalid> - 2014-06-23 21:10 -0400
                Re: is that possible to include a small PNG file as part of Java class? Jeff Higgins <jeff@invalid.invalid> - 2014-06-23 21:23 -0400
                Re: is that possible to include a small PNG file as part of Java class? Jeff Higgins <jeff@invalid.invalid> - 2014-06-24 16:17 -0400
          Re: is that possible to include a small PNG file as part of Java class? Jeff Higgins <jeff@invalid.invalid> - 2014-06-23 16:33 -0400
        Re: is that possible to include a small PNG file as part of Java class? Jeff Higgins <jeff@invalid.invalid> - 2014-06-24 16:00 -0400
  Re: is that possible to include a small PNG file as part of Java class? Andreas Leitgeb <avl@auth.logic.tuwien.ac.at> - 2014-06-24 17:17 +0000
  Re: is that possible to include a small PNG file as part of Java class? Roedy Green <see_website@mindprod.com.invalid> - 2014-06-24 11:11 -0700

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