need help, I'm frustrated

[Hao Jiang-3]

Currently I'm working on v1.37u, to write/modify a plugin.
 
The idea is after open an image (customer file type, grayscale), need to
draw (or just display) some points on it. Additional, after user zoom
the image in, the size of those points won't be enlarged, so the user is
able to find the precise position of every point.
 
After referred to some plugin's code, and numerous tests, that's what I
got so far
 
class CustomerWindow extends ImageWindow{
 
Vector HDPoints;
List pointsList = new ArrayList();
 
// some other methods
 
void getPoints(){
//read file, get points and put into HDPoints
}
 
void drawPoints(){
    ImagePlus imp = WindowManager.getCurrentImage();
    ImageCanvas ic = imp.getCanvas();
    double m = ic.getmagnification();
    int w = new double((double)3/m).intValue();  //w changed when zoom
value changed, keep it relative the same
 
    pointsList.clear();
 
    for(int i=0; i<HDPoints.size(); i++){
        Object o = HDPoints.elementAt(i);
        int x = o.getx();
        int y = o.gety();
        String color = o.getColor();
 
        OvalRoi oval = new OvalRoi(x-w/2, y-w/2, w, w);
        oval.setColor(color);
        pointsList.add(oval);
        IJ.getImage().setRoi(oval);
    }
 
    for(Iterator it = pointsList.iterator(); it.hasNext();){
        ShapeRoi roi = new ShapeRoi((OvalRoi)it.next());
        IJ.getImage().setRoi(roi);
    }
}
 
If there is only one point, this works perfectly fine, I get everything
I wanted. However, if there are many points, then except that last one,
points showed up one by one on image, but disappeared in the end.
 
Please help me,
 
Thank you very much
 
Hao Jiang


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[dscho]

Hi,

On Tue, 15 Jul 2008, Hao Jiang wrote:

>  
>     for(Iterator it = pointsList.iterator(); it.hasNext();){
>         ShapeRoi roi = new ShapeRoi((OvalRoi)it.next());
>         IJ.getImage().setRoi(roi);

This will set a new roi with every iteration.  That is the reason why it
does not work.

You need to use the or() method of ShapeRoi to extend the first, and only
in the end, i.e. _after_ the loop, set the ROI.  IOW:

        ShapeRoi roi = null;
        Iterator it = pointsList.iterator();
        while (it.hasNext()) {
                ShapeRoi oval = new ShapeRoi((OvalRoi)it.next());
                roi = roi == null ? oval : roi.or(oval);
        }
        IJ.getImage().setRoi(roi);

Of course, you can do that already in the first for() loop.  But you get
the idea.

Hth,
Dscho

[Hao Jiang-3]

 Thank you for you reply, I tried this, it worked fine with only few
points. However, for one test with 20K points, it took almost forever to
finish. I believe it's because of "or" operation.

Hao



-----Original Message-----
From: Johannes Schindelin [mailto:[hidden email]]
Sent: Tuesday, July 15, 2008 7:14 PM
To: Hao Jiang
Cc: [hidden email]
Subject: Re: need help, I'm frustrated

Hi,

On Tue, 15 Jul 2008, Hao Jiang wrote:

>  
>     for(Iterator it = pointsList.iterator(); it.hasNext();){
>         ShapeRoi roi = new ShapeRoi((OvalRoi)it.next());
>         IJ.getImage().setRoi(roi);

This will set a new roi with every iteration.  That is the reason why it
does not work.

You need to use the or() method of ShapeRoi to extend the first, and
only in the end, i.e. _after_ the loop, set the ROI.  IOW:

        ShapeRoi roi = null;
        Iterator it = pointsList.iterator();
        while (it.hasNext()) {
                ShapeRoi oval = new ShapeRoi((OvalRoi)it.next());
                roi = roi == null ? oval : roi.or(oval);
        }
        IJ.getImage().setRoi(roi);

Of course, you can do that already in the first for() loop.  But you get
the idea.

Hth,
Dscho





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[dscho]

Hi,

On Thu, 17 Jul 2008, Hao Jiang wrote:

>  Thank you for you reply, I tried this, it worked fine with only few
> points. However, for one test with 20K points, it took almost forever to
> finish. I believe it's because of "or" operation.

That is no wonder.  If you want this to scale to an insane amount of
points, you will need to do some optimization, and actually understand
what the code of "or()" does.  You will need to read up on java.awt.Shape.

Hth,
Dscho

[Wayne Rasband]

 > Thank you for you reply, I tried this, it worked fine with only few
 > points. However, for one test with 20K points, it took almost
 > forever to finish. I believe it's because of "or" operation.

This macro displays 20,000 points as a point selection in just a few
seconds.

   size = 2000;
   count = 20000;
   x = newArray(count);
   y = newArray(count);
   for (i=0; i<count; i++) {
      x[i] = random*size;
      y[i] = random*size;
   }
   newImage("Test", "8-bit Black", size, size, 1);
   run("Point Tool...", "mark=0 selection=yellow");
   makeSelection("point", x, y);

-wayne

[Hao Jiang-3]

Hi Wayne, I've not problem to run your macro, but just can't make it
work in my code.  

public void drawPoints()
{
        if (HDPoints == null)
        {
                return;
        }

        imp = WindowManager.getCurrentImage();
        ImageCanvas ic = imp.getCanvas();
       
        fi = (IntermapFileInfo)imp.getOriginalFileInfo();
        int x, y;
        Calibration cal = imp.getCalibration();
        Rectangle r = imp.getWindow().getCanvas().getSrcRect();

        displayList = new Vector();


        for (int i = 0; i < HDPoints.size(); i++)
        {
                x =
(int)(((HeightSamplePoint)HDPoints.elementAt(i)).getX() /
(fi.decimation));
                y =
(int)(((HeightSamplePoint)HDPoints.elementAt(i)).getY() /
(fi.decimation)) + (int)(cal.yOrigin / fi.decimation);

                if (y >= 0 && y <= fi.height && x >= r.getX() && x <=
r.getX() + r.getWidth())
                {
                        displayList.add(HDPoints.elementAt(i));
                }
        }
       
        int size = displayList.size();

        int[] xPoints = new int[size];
        int[] yPoints = new int[size];

        for(int i=0; i<size; i++){
                HeightSamplePoint point =
(HeightSamplePoint)displayList.elementAt(i);
                xPoints[i]=(int)point.getX();
                yPoints[i]=(int)point.getY();
        }

        Roi roi = new PointRoi(xPoints, yPoints, size);
        IJ.getImage().setRoi(roi);
}

I used log to output points in the 2nd for loop, all there, but just
can't draw them on image

What else I have missed?

Thanks

Hao



-----Original Message-----
From: ImageJ Interest Group [mailto:[hidden email]] On Behalf Of
Wayne Rasband
Sent: Thursday, July 17, 2008 12:55 PM
To: [hidden email]
Subject: Re: need help, I'm frustrated


 > Thank you for you reply, I tried this, it worked fine with only few
> points. However, for one test with 20K points, it took almost  >
forever to finish. I believe it's because of "or" operation.

This macro displays 20,000 points as a point selection in just a few
seconds.

   size = 2000;
   count = 20000;
   x = newArray(count);
   y = newArray(count);
   for (i=0; i<count; i++) {
      x[i] = random*size;
      y[i] = random*size;
   }
   newImage("Test", "8-bit Black", size, size, 1);
   run("Point Tool...", "mark=0 selection=yellow");
   makeSelection("point", x, y);

-wayne




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Technologies or the sender immediately by telephone at the number
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