Finding handles to ROI objects such as drawline

Until the advent of drawline, it was easy to find the handle to a line objects created using imline:

fighl = figure;
axhl = axes(fighl);
imagesc(axhl, rand(100));
colormap gray
imline(axhl, [10 50; 80 50])
findobj(axhl, 'type', 'line')
ans = 

  4×1 Line array:

  Line    (end point 2)
  Line    (end point 1)
  Line    (top line)
  Line    (bottom line)

Repeating the same functionality using drawline:

fighl = figure;
axhl = axes(fighl);
imagesc(axhl, rand(100));
colormap gray
drawline(axhl, 'position', [10 50; 80 50])
findobj(axhl, 'type', 'line')
ans = 

  0×0 empty GraphicsPlaceholder array.

I know that this object exists:

>> findobj(axhl)

ans = 

  3×1 graphics array:

  Axes
  Line
  Image

However, any attempt to access the object handle returns an empty placeholder.

I need to be able to find line objects without having to explicitly store their handles.

Is there a way to achieve this?

[Xingwang Yong]

If I get the 4x1 Line array, can I get the original handle? So that I can call createMask()

h = imline();
mask = h.createMask();

% how to get h using the 4x1 Line array?

Answer 1

[Adam Danz]

h = findobj(axhl, 'type', 'images.roi.line');

The object created by drawline is different from regular line objects.

But the best solution is to just store the output handle.

h = drawline(___)

[Richard McWilliam]

Great, thanks for this.

Looks like I need to get up to speed on ROI classes...