I think I've discovered at least one problem that you are running into -
we don't have an optimized loop to convert from 1-bit binary images to
INT_RGB images. Further, the general code that gets used doesn't take
the best advantage of the existing optimized loops that do exist.
We only have a loop to convert from 1-bit to INT_ARGB so if you
drawImage directly to an INT_RGB image then it will have to do a slower
work-around technique.
To find this out (I thought this had been mentioned a couple of years
ago on some forum, but I can't seem to find it with a search), there is
a hidden utility in the JDK where you can get the system to print out
the supported loops. It was originally designed so that you could just
execute:
% java sun.java2d.loops.GraphicsPrimitiveMgr list
and it would print out all of the built-in rendering loops in the
system. Unfortunately we broke this at some point and so now it
generates an error that a required native method isn't found. The
workaround is still simple - compile and run the following very short
program and it will do the same thing:
public class GPMgr {
public static void main(String argv[]) {
java.awt.Toolkit.getDefaultToolkit();
sun.java2d.loops.GraphicsPrimitiveMgr.main(argv);
}
}
% javac GPMgr.java
% java GPMgr list
I grepped for "Blit" and "ByteBinary" and discovered that there are only
convert (Blit(XX, SrcNoEa, YY)) loops for 1-bit to ARGB. The thing that
surprised me, though, was that it took 4 times longer even despite the
workarounds. I quickly ran a trace on copying a 1-bit image to INT_RGB
and discovered that it ends up using a loop called
"OpaqueCopyAnyToIntArgb" which is a Java loop that uses a couple of
method calls per pixel. There are faster ways it could do this, even
without creating a specific loop for this case, but it will take a bit
of elbow grease as the logic in that part of the system is a little
obscure...
...jim
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