Problems in polygonal selection with very deep zooming

[claczny]

When zooming in deeply and doing a polygonal selection it seems that the decision if a point belongs to a cluster (contains()) becomes problematic:
The polygon clearly contains more than 2 sequences.

This seems to happen only when zooming in very deeply so it may not be a frequent problem. Nevertheless, this needs to be checked/fixed.

[claczny]

This seems to be related to the rounding which is necessary for Awt.Polygon.addPoint(int x, int y). Since we need to provide int but the mouse clicks produce double, we have a significant loss of precision here. The attached figure illustrates this nicely: two of the y-values get rounded to 64 (see debug message in background terminal) and thus only one point is left. The upper points have y > 64 and are thus ignored.

While the scale-factor (scale) in DataSetFactory.createDataSetFromPointFile(new FileInputStream(inpointsfile), labelsIS, scale); allows to overcome this to a certain extent (simply use a "large enough" scaling factor) there might always be situations where the zooming is so deep that the rounding will cause problems.