Re: What's the best/fastest way to access image data
Thank you. That's truly impressive. Of course, now I have about six
new things to learn :-)
Looking at your earlier post, I can see where invoking getRGB 3
million times might result in sub-optimal performance. I must say that
I'm a little surprised to see something like that in a core API. But
it explains a lot.
I modified my test program based on your example, drawing a few
primitives to the BufferedImage after it was created and inspecting
the contents of the rawARGB array to see if it changed. It worked
like a charm. And, as you say, the speed improvement is easily a
factor of 10.
I do have a question. From your code, it looks like the trick is to
supply the BufferedImage constructor with the memory that you want it
to write to so that you don't have to ask for it later on. That makes
sense. The thing I was wondering about is if the resulting
BufferedImage will have the same performance as the ones which I am
currently creating with the less-advanced constructor. The real core
function of my application is in the rendering of graphics (using
Graphics2D) to produce the raw images. The rendering involves a lot of
graphics primitives, so performance is critical. The image processing
that I am doing is really just an extra.
Naturally, I'm going to do my homework (read up on the API elements
you used and also do a lot of testing) before I commit to an approach,
but I was wondering whether I should be alert to any special tricks or
techniques as I do so.
Thanks again for your well-informed and insightful suggestion!
Gary
On Nov 2, 5:30 pm, markspace <nos...@nowhere.com> wrote:
John B. Matthews wrote:
It should be possible to operate on the Raster directly:
<http://sites.google.com/site/drjohnbmatthews/raster>
Of course, that still leaves leaves 2000 x 1500 pixels work on.
I came up with the code below as a direct replacement for the OP's
example. However, I'm not really sure if this is what he wants or not.
It does run 10x faster than his example.
public class Main
{
public static void main( String[] args )
{
for( int i = 0; i < 5; i++ ) {
long startTime = System.nanoTime();
SinglePixelPackedSampleModel neoSPPSM =
new SinglePixelPackedSampleMod=
el(
DataBuffer.TYPE_INT, 2000,
1500,
new int[]{0xFF0000, 0xFF00, 0x=
FF, 0xFF000000} );
int[] rawARGB = new int[2000 * 1500];
DataBufferInt neoDBI = new DataBufferInt( ra=
wARGB, 2000 *
1500 );
WritableRaster neoWR =
Raster.createWritableRaster( n=
eoSPPSM, neoDBI,
null );
DirectColorModel dcm = new DirectColorModel(=
32, 0xFF0000,
0xFF00,
0xFF, 0xFF000000 );
BufferedImage image2 = new BufferedImage( dc=
m, neoWR,
false, null );
long endTime = System.nanoTime();
System.out.println( "Loop time (" + image2.has=
hCode() +
"): " +
(endTime - startTime) / 100000=
0 );
}
}