Convert freehand and selection brush ROIs to a polygon selection with user editable handles.

If a freehand selection or a selection brush ROI is drawn, the only way to modify the shape of the ROI is to either 'paint' extra geometry or merge the ROI with another region using the ROI Manager. This could be made easier such selections could be converted to a polygon selection which has modifiable handles. On conversion, the user could specify point placement by a 'smoothness' factor (higher values result in more vertices in the polygon), the elimination of non-selected 'islands', and the splitting of isolated selected regions into unique ROIs. by Lee Pang — last modified 2007-05-28 13:51

  Freehand and Selection Brush ROI conversion
Posted by G. Landini at 2007-05-28 13:49
This can be done already with a very simple macro:

getSelectionCoordinates(x, y);
run("Select None");
makeSelection("polygon", x, y); 

  Works, kind of ...
Posted by Lee Pang at 2007-05-29 05:17
The macro you suggested works with the freehand selections but with 
outlines made with the Selection Brush tool, it returns a rectangular 
ROI equivalent to the bounding box of the original selection.

  Try this...
Posted by G. Landini at 2007-05-29 12:51
The macro below works if the ROI is a composite one (for example 
created with the Brush tool) and it has no holes in it. (Use the 
above one for non-composite ROIs and the one below for composite ones).


The roiManager should be empty (or closed) to run this correctly:

roiManager("Add");
run("Add to Manager ");
roiManager("Select", 0);
roiManager("Split");
roiManager("Select", 1);
getSelectionCoordinates(x, y);
run("Select None");
makeSelection("polygon", x, y);
roiManager("Add");
roiManager("Select", 0);
roiManager("Delete");
roiManager("Select", 0);
roiManager("Delete");
roiManager("Select", 0);
roiManager("Delete"); 

  Thanks!
Posted by Lee Pang at 2007-06-05 22:00
This worked. It tends to exclude one ROI from the manager, 
but this is easily solved by hitting the 'Add' button after 
the macro has run.

  ROI2PolylineROI.txt macro
Posted by G. Landini at 2007-06-06 11:49
A little improvement from the previous.
The macro below deals with all ROI types (and it also 
fixes some extra lines the previous macro).


// ROI2PolylineROI
// G. Landini 6/6/2007
// converts a ROI to Poly-line/gon ROI
// ROI should be in 1 piece and not contain holes
// Note that for composite ROIs, it will delete all other ROIs
// currently in the manager!

t=selectionType();

if (t==1 || t==3 || t==4) {
getSelectionCoordinates(x, y);
run("Select None");
makeSelection("polygon", x, y);
}

if (t==7) {
getSelectionCoordinates(x, y);
run("Select None");
makeSelection("polyline", x, y);
}

if (t==9) {
roiManager("Deselect");
roiManager("Delete");
roiManager("Add");
roiManager("Select", 0);
roiManager("Split");
roiManager("Select", 1);
getSelectionCoordinates(x, y);
run("Select None");
makeSelection("polygon", x, y);
roiManager("Add");
roiManager("Select", 0);
roiManager("Delete");
roiManager("Select", 0);
roiManager("Delete");
roiManager("Select", 0);
}