Add a user define property to freehand object

Hi there,

I know that Freehand object does not have a rotatable property like drawrectangle.

Can anyone tell me please how can I add this property to Freehand, so I can rotate my object on the figure?

Nikan

Answer 1

[Adam Danz]

You could apply your own rotation using a rotation matrix.

% anonymous function to center the obj at (0,0), 
% rotate it, and move it back to its original
% center point. 
ROIxy = @(h)[h.Position(:,1),h.Position(:,2)]; 
rotMat = @(h,th)([cosd(th), -sind(th); sind(th), cosd(th)]*(ROIxy(h)-mean(ROIxy(h)))')' + mean(ROIxy(h));

To use the functions above, create a freehand object and they apply the rotation angle in degrees.

Example:

% create freehand obj
z = drawfreehand();

% Plot the center point (red x)
hold on
xl = xlim(); yl = ylim(); 
cnt = mean(ROIxy(z)); % center point
plot(cnt(1),cnt(2),'rx')
xlim(xl); ylim(yl) % see [1]

% Continually rotate ROI by 12 degrees CCW
while true
    z.Position = rotMat(z,12);  % see [2]
    drawnow
end

Footnotes

[1] I don't know why the axis limits change when adding the + marker but this resets the original axis limits.

[2] rotMat(h,th) rotates ROI object h by th degrees (negative is CW rotation)