Bugs: regions

The following self-intersecting lines can be used to create a line:

chips> clear()
chips> x = [0.1, 0.9, 0.9, 0.1, 0.1]
chips> y = [0.1,0.9, 0.1, 0.9, 0.1]
chips> add_line(x, y)

but not a region:

chips> add_region(x, y)
chips ERROR: Region creation attempt failed

Regions may have sections missing on print out to postscript or PDF formats when sections of the region appear outside the frame or window. To avoid this, ensure the plot displays all the region or, if possible, filter the region so that only those parts within the plot area are used.

For an example of this, see the discussion of the FOV overlay gallery example.

If the x,y arrays passed to add_region are closed - that is the last point equals the first point - then the ChIPS server will crash and destroy any existing visualization. Further commands will automatically create a new server, but you can not use undo to restore the original state.

The work around is to ensure that the region is not closed.

For example:

  chips> x = [0.1, 0.9, 0.9, 0.1]
  chips> y = [0.1, 0.1, 0.9, 0.9]
  chips> add_plot(["style", "open"])
  chips> add_region(x, y)
  chips> info()

  Window [win1]
    Frame [frm1]
      Plot [plot1]   (0.15,0.15)  .. (0.90,0.90)
        Border bottom [bx1]  top [bx2]  left [by1]  right [by2]
        Region [reg1] 

works, but if you say

  chips> x = [0.1, 0.9, 0.9, 0.1, 0.1]
  chips> y = [0.1, 0.1, 0.9, 0.9, 0.1]
  chips> add_region() 

then the ChIPS window, and - if displayed - the GUI, will disappear.