minimizing image bit depth and resolution for better performance?

[trembovetski]

I think the problem could be a rounding error somewhere. Up to a point your rotate(angle)...rotate(-angle)
turn the transform on and off, but at some angle the restored transform that's left after rotate(-angle) may
have some tiny amount of rotation left because of rounding error, which means that all the rest of the
rendering will be rendered transformed, even though you don't see it.

So one suggestion would be to instead of rotate/unrotate try savetransform/rotate/restoretransform .

Also, I can't find it, but I believe there was a bug fixed in mustang (jdk6.0) which at least partly addressed
this. Could you please try mustang (http://mustang.dev/java.net)?

Thanks,
  Dmitri
Java2D Team

[rickyhaggett]

This sounds pretty plausible, and it reminded me of the last thing I did in desperation last night before going to bed - I tried casting my double to a float, i.e.

g.rotate((float)angle);
...
g.rotate(-(float)angle);

This seemed to have the effect of changing the angles for which the slow-down occured (so angles which previously were fine now caused problems, and angles which were slow were now fine).

I'll try your suggestion this evening, and check out mustang too..

Cheers,

Ricky

[rickyhaggett]

Marvellous!  That fix works - thanks Dmitri.

I now have:

AffineTransform transform = g.getTransform();
g.translate(x, y);
g.rotate(angle);
...
g.setTransform(transform);

.. and I'm back in the wonderful world of 60fps. I'm guessing this way is also slightly more optimal.

For reference, the values causing the trouble were:

0.41887902047863906 (Math.toRadians(24))
6.073745796940266 (Math.toRadians(348))
1.4311699866353502 (Math.toRadians(82)).

Thanks for the help. I've downloaded Mustang - will check it out soon

Ricky