Re: Testing Intersection with A Rectangle(2D) w/No Area

From: Fred L. Kleinschmidt (fred.l.kleinschmidt_at_nospam_boeing.com)
Date: 02/18/04 

Date: Wed, 18 Feb 2004 17:21:39 GMT

Aaron Davies wrote:
>
> How do I test a rectangle for intersection with another rectangle which has
> no area, ie where the y1 and y2 co-ords are the same? All the intersect
> methods from awt.geom.Rectangle2D.* and awt.geom.Area seem to test for
> intersection with the interior of the rectangle, but that always returns
> false for a degenerate rect which is equivalent to a line. Do I have to
> create that equivalent line and test intersectsLine, or is there a better
> way?

      Rectangle r = new Rectangle( 1,0,10,10);
      Rectangle s = new Rectangle( 0, 5, 11, 0);
      if ( r.intersects(s) ) {
         System.out.println( "r intersects s");
      }
      if ( s.intersects(r) ) {
         System.out.println( "s intersects r");
      }
      Rectangle q = r.intersection(s);
      System.out.println( "intersection: "+q);

When this is executed, it verifies that r and s intersect, regardless of
whether you use r.intersects(s) or s.intersects(r). And s is a
degenerate rectangle with no height. Are you sure your rectangles
actually intersect? 

-- 
Fred L. Kleinschmidt
Boeing Associate Technical Fellow
Technical Architect, Common User Interface Services
M/S 2R-94  (206)544-5225

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