setPositionConstraintFcn

Starting in R2018b, a new set of ROI objects replaces the existing set of ROI objects. The new objects provide more functional capabilities, such as face color transparency. The new classes also support events that you can use to respond to changes in your ROI such as moving or being clicked. Although there are no plans to remove the old ROI objects at this time, switch to the new ROIs to take advantage of the additional capabilities and flexibility. For more information on creating ROIs using the new ROI functions, see Create ROI Shapes.

In the existing ROIs, you can create a function that controls where you can draw or move an ROI. You then register the position constraint function with the ROI. To specify the area when you can draw or move an ROI, use the DrawingArea property.

imshow("cell.tif")
h = impoint(gca,20,60);
% Make a function that constrains movement of the point
x = get(gca,"XLim");
y = get(gca,"YLim");
fcn = makeConstrainToRectFcn("impoint",x,y);;
% Apply the constraint function to the ROI.
setPositionConstraintFcn(h,fcn);

imshow("cell.tif")
h = drawpoint(gca,"Position",[20 60])
[height width] = size(I); %Get image dimensions
h.DrawingArea = [10,10,(width-20),(height-20)];