Graphics2D object retrieved from Canvas is volitile...

[java2d]

I first thought this was a bug in the 1.6.0.14 plugin.  But perhaps it is just that the Graphics2D object retrieved from a Canvas object is volatile.  Although I have never seen a Graphics2D object to be volatile except when it was retrieved from a BufferStrategy.

This is what I see.

When I dragged an applet to the desktop, I would lose my Canvas Graphics2D object. In other words when I init my Canvas:

canvasGraphic = (Graphics2D)this.getGraphics(); // this is a Canvas

gives me back a volitile canvasGraphic. When I drag the applet to the desktop, canvasGraphics is no longer valid. It's not null -- just not valid. I cannot use it to draw with. The applet still responds to paint(Graphics g) calls because g is a new Graphics object.

So when I redraw my pixel buffer, I have to get the canvasGraphics object each time to be sure that it is still valid like this:

I call this method now for every frame I draw when the user pans/tilts/zooms.
public void newPixels()
{
canvasGraphic= (Graphics2D)this.getGraphics();
canvasGraphic.drawImage(paintImage, 0, 0, thisW, thisH, this);
}

It used to look like:
public void newPixels()
{
canvasGraphic.drawImage(paintImage, 0, 0, thisW, thisH, this);
}

And the above works fine until the applet is dragged to the desktop, then canvasGraphic becomes invalid (or something) and drawImage() doesn't draw the image on the Canvas.

Is this a bug??? Is this the way it's supposed to be???  I don't know.

Open:
http://pancyl.com/

I've added the code to get a new Graphics2D object each time I draw my pixel buffer. It works now just like before 1.6.0.14. I don't recall ever having to do this.  But I was using BufferStrategy and I was getting the Graphics2D object each time I drew.  I changed to using an unmanaged BufferedImage that I draw directly onto my Canvas.  I didn't know that the Canvas graphics object was volatile.  I don't recall ever having to get the graphics object from the Canvas each time I draw into it.  Did something change?
[Message sent by forum member 'demonduck' (demonduck)]

http://forums.java.net/jive/thread.jspa?messageID=353271

===========================================================================
To unsubscribe, send email to listserv@... and include in the body
of the message "signoff JAVA2D-INTEREST".  For general help, send email to
listserv@... and include in the body of the message "help".

[Dmitri Trembovetski]

java2d@... wrote:

> I first thought this was a bug in the 1.6.0.14 plugin.  But perhaps it is just that the Graphics2D object retrieved from a Canvas object is volatile.  Although I have never seen a Graphics2D object to be volatile except when it was retrieved from a BufferStrategy.
>
> This is what I see.
>
> When I dragged an applet to the desktop, I would lose my Canvas Graphics2D object. In other words when I init my Canvas:
>
> canvasGraphic = (Graphics2D)this.getGraphics(); // this is a Canvas
>
> gives me back a volitile canvasGraphic. When I drag the applet to the desktop, canvasGraphics is no longer valid. It's not null -- just not valid. I cannot use it to draw with. The applet still responds to paint(Graphics g) calls because g is a new Graphics object.
>
> So when I redraw my pixel buffer, I have to get the canvasGraphics object each time to be sure that it is still valid like this:
>
> I call this method now for every frame I draw when the user pans/tilts/zooms.
> public void newPixels()
> {
> canvasGraphic= (Graphics2D)this.getGraphics();
> canvasGraphic.drawImage(paintImage, 0, 0, thisW, thisH, this);
> }
>
> It used to look like:
> public void newPixels()
> {
> canvasGraphic.drawImage(paintImage, 0, 0, thisW, thisH, this);
> }
>
> And the above works fine until the applet is dragged to the desktop, then canvasGraphic becomes invalid (or something) and drawImage() doesn't draw the image on the Canvas.
>
> Is this a bug??? Is this the way it's supposed to be???  I don't know.

   Creating a new graphics context for every rendering cycle is the preferred
way actually, but it is supposed to work either way, so it's a bug.

> Open:
> http://pancyl.com/
>
> I've added the code to get a new Graphics2D object each time I draw my pixel buffer. It works now just like before 1.6.0.14. I don't recall ever having to do this.  But I was using BufferStrategy and I was getting the Graphics2D object each time I drew.  I changed to using an unmanaged BufferedImage that I draw directly onto my Canvas.  I didn't know that the Canvas graphics object was volatile.  I don't recall ever having to get the graphics object from the Canvas each time I draw into it.  Did something change?

   I don't think anything changed in 6u14 that'd do that, but this bug may have
been introduced in 6u10.

   Thanks,
     Dmitri

===========================================================================
To unsubscribe, send email to listserv@... and include in the body
of the message "signoff JAVA2D-INTEREST".  For general help, send email to
listserv@... and include in the body of the message "help".

[java2d]

> java2d@... wrote:
> > I first thought this was a bug in the 1.6.0.14
>> plugin.  But perhaps it is just that the Graphics2D
>>object retrieved from a Canvas object is volatile.
>> Is this a bug??? Is this the way it's supposed to
>>  be???  I don't know.

> Creating a new graphics context for every
>  rendering cycle is the preferred
> ay actually, but it is supposed to work either way,
> so it's a bug.
>

>   Dmitri


I'll leave it up to you (or somebody) to file a bug report.  I have the work around which doesn't appear to impact performance so I'm pretty much done with this.
[Message sent by forum member 'demonduck' (demonduck)]

http://forums.java.net/jive/thread.jspa?messageID=353440

===========================================================================
To unsubscribe, send email to listserv@... and include in the body
of the message "signoff JAVA2D-INTEREST".  For general help, send email to
listserv@... and include in the body of the message "help".

[Dmitri Trembovetski]

   I filed a bug
     6855841: D3D: graphics object doesn't get revalidated for applets which
were dragged out of the browser

   Will show up on bug parade later today.

   Thanks,
     Dmitri


java2d@... wrote:

>> java2d@... wrote:
>>> I first thought this was a bug in the 1.6.0.14
>>> plugin.  But perhaps it is just that the Graphics2D
>>> object retrieved from a Canvas object is volatile.
>>> Is this a bug??? Is this the way it's supposed to
>>>  be???  I don't know.
>
>> Creating a new graphics context for every
>>  rendering cycle is the preferred
>> ay actually, but it is supposed to work either way,
>> so it's a bug.
>>
>
>>   Dmitri
>
>
> I'll leave it up to you (or somebody) to file a bug report.  I have the work around which doesn't appear to impact performance so I'm pretty much done with this.
> [Message sent by forum member 'demonduck' (demonduck)]
>
> http://forums.java.net/jive/thread.jspa?messageID=353440
>
> ===========================================================================
> To unsubscribe, send email to listserv@... and include in the body
> of the message "signoff JAVA2D-INTEREST".  For general help, send email to
> listserv@... and include in the body of the message "help".

===========================================================================
To unsubscribe, send email to listserv@... and include in the body
of the message "signoff JAVA2D-INTEREST".  For general help, send email to
listserv@... and include in the body of the message "help".

[java2d]

Thank you...
[Message sent by forum member 'demonduck' (demonduck)]

http://forums.java.net/jive/thread.jspa?messageID=353452

===========================================================================
To unsubscribe, send email to listserv@... and include in the body
of the message "signoff JAVA2D-INTEREST".  For general help, send email to
listserv@... and include in the body of the message "help".