Re: Point Tool >> getSelectionBounds >> Discrepant Coordinates

Posted by Herbie on Jan 08, 2021; 12:16pm
URL: http://imagej.273.s1.nabble.com/behavior-of-variable-when-function-is-called-tp5024336p5024343.html

Greetings Peter,

yes that explains a lot--thanks!

Taking the "floor" instead of "round" appears being a bit strange.

__________
As suggested by Michael Schmid, I'm now using:
x_0 = (int)Math.round( roi.getFloatBounds().getX() );
y_0 = (int)Math.round( roi.getFloatBounds().getY() );
__________
BTW
x_0 = (int)Math.round( roi.getBounds().getX() );
y_0 = (int)Math.round( roi.getBounds().getY() );
doesn't solve the problem, although roi.getBounds().getX() is said to
return a Double as well.

Regards

Herbie

::::::::::::::::::::::::::::::::::::::::
Am 08.01.21 um 12:28 schrieb Peter Haub:

> Hi Herbie,
>
> the macro functions calls the function
> getBounds() in Functions.java.
> This functions returns floating point values after internally calling
> roi.getFloatBounds() .
>
> Your plugin returns roi.getBounds().x and roi.getBounds().y
> which are floor(roi.getFloatBounds().x) and floor(roi.getFloatBounds().y).
>
> Hope that helps
>
> Peter
>
> On 08.01.2021 11:10, Herbie wrote:
>> Dear experts and especially Wayne,
>>
>> please consider the following situation:
>>
>> A___________________________________________
>> 1. Open an 8-bit image with zoom e.g. 400%
>> 2. Use the point tool
>> 3. Make a point selection at x=5, y=10 according
>>    to the coordinates shown in the IJ-toolbar
>>
>> B___________________________________________
>> 1. Run the macro:
>>    //
>>    getSelectionBounds( x, y, width, height );
>>    print( round(x), round(y) );
>>    //
>> 2. The log-window shows:
>>    5 10
>>
>> C___________________________________________
>> 1. Run the compiled plugin:
>>    //
>>    import java.awt.*;
>>    import ij.*;
>>    import ij.gui.*;
>>    import ij.process.*;
>>    import ij.plugin.filter.PlugInFilter;
>>    public class My_PlugInFilter implements PlugInFilter {
>>     protected ImagePlus imp;
>>     public int setup( String arg, ImagePlus imp ) {
>>         if ( IJ.versionLessThan( "1.53g" ) )
>>             return DONE;
>>         if( imp != null ) {
>>             this.imp = imp;
>>         }
>>         return DOES_8G;
>>     }
>>     public void run( ImageProcessor ip ) {
>>         Roi roi = imp.getRoi();
>>         int x_0 = (int)Math.round( roi.getBounds().x );
>>         int y_0 = (int)Math.round( roi.getBounds().y );
>>         IJ.log( ""+x_0+"; "+y_0 );
>>     }
>>    }
>>    //
>> 2. The log-window *sometimes* shows:
>>    5; 10
>> 3. However, in many cases the result is "5; 9", "4; 9", or "4; 10"
>> 4. The plugin-result depends on how the point selection was set in the
>> zoomed image
>> 5. The discrepancy is not observed if the image is not initially zoomed
>>
>> What am I doing wrong?
>>
>> Regards
>>
>> Herbie
>>
>> --
>> ImageJ mailing list: http://imagej.nih.gov/ij/list.html
>

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