Method trimPolygon

ij/src/main/java/ij/plugin/Selection.java:368–405

(PolygonRoi roi, double length)

	}
	
	PolygonRoi trimPolygon(PolygonRoi roi, double length) {
		int[] x = roi.getXCoordinates();
		int[] y = roi.getYCoordinates();
		int n = roi.getNCoordinates();
		x = smooth(x, n);
		y = smooth(y, n);
		float[] curvature = getCurvature(x, y, n);
		Rectangle r = roi.getBounds();
		double threshold = rodbard(length);
		double distance = Math.sqrt((x[1]-x[0])*(x[1]-x[0])+(y[1]-y[0])*(y[1]-y[0]));
		x[0] += r.x; y[0]+=r.y;
		int i2 = 1;
		int x1,y1,x2=0,y2=0;
		for (int i=1; i<n-1; i++) {
			x1=x[i]; y1=y[i]; x2=x[i+1]; y2=y[i+1];
			distance += Math.sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1)) + 1;
			distance += curvature[i]*2;
			if (distance>=threshold) {
				x[i2] = x2 + r.x;
				y[i2] = y2 + r.y;
				i2++;
				distance = 0.0;
			}
		}
		int type = roi.getType()==Roi.FREELINE?Roi.POLYLINE:Roi.POLYGON;
		if (type==Roi.POLYLINE && distance>0.0) {
			x[i2] = x2 + r.x;
			y[i2] = y2 + r.y;
			i2++;
		}		
		PolygonRoi p = new PolygonRoi(x, y, i2, type);
		if (roi.getStroke()!=null)
			p.setStrokeWidth(roi.getStrokeWidth());
		p.setStrokeColor(roi.getStrokeColor());
		p.setName(roi.getName());
		imp.setRoi(p);
		return p;
	}
	
	double rodbard(double x) {
		// y = c*((a-x/(x-d))^(1/b)