Re: What's the best/fastest way to access image data

On Nov 2, 12:37 pm, markspace <nos...@nowhere.com> wrote:


Sure. The code follows. The actual application is generating content
based on data analysis performed in background threads (behind the
scenes) and storing it in BufferedImage objects. There are a number of
different kinds of analysis routines running (some of them quite
complicated). At run time, several images may get overlaid on top of
each other to make make one composite. This, the images are declared
TYPE_INT_ARGB when the application creates them. So far, I have been
favorably impressed by Java's performance.

Anyway, you can see where I don't think that asynchronous behavior is
the issue, though I could certainly be wrong.

This snippet of code simulates the conditions under which I am
observing the performance issues. Running this on my computer, I
observed 200 millisecond access time. I set the command-line memory
option to -Xmx512m to ensure plenty of memory for the test.

Hope this helps.

Gary

import java.awt.image.BufferedImage;

/**
 *
 */
public class TimeTest {

    public static void main(String args[]) {
        TimeTest test = new TimeTest();
        for(int i=0; i<5; i++)
            test.run();
    }

    public void run() {
        BufferedImage image = new BufferedImage(
                2000,
                1500,
                BufferedImage.TYPE_INT_ARGB);

        // Diagnostic graphics operations to exercise the
        // idea that some work had been done before we tried
        // extracting the contents of the image. In testing,
        // doesn't seem to make much difference.
        //Graphics2D g2d = image.createGraphics();
        //g2d.setColor(Color.ORANGE);
        //g2d.drawRect(0, 0, 500, 600);
        //g2d.dispose();
        //try {
        // Thread.sleep(1000);
        //} catch (InterruptedException ex) {
        //}

        long time0 = System.currentTimeMillis();
        int w = image.getWidth();
        int h = image.getHeight();
        int n = w * h;
        int[] rgb = image.getRGB(0, 0, w, h, new int[n], 0, w);
        long time1 = System.currentTimeMillis();
        long accessTime = time1 - time0;
        System.out.println("Access time " + accessTime);
        System.out.flush();
    }
}


);


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