set ROI attributes during runtime - fix position and scale programmatically

[Cho]

Hi,

I have a question regarding ROIs. I have an image with a ROI which is movable by the user. Upon clicking a "save ROI" button I wish to save the ROI to do some analysis with it. In principle I want to display the saved ROI in the image but make it fixed in position and size so that it cannot be altered by the user anymore. Here's how I thought how I would go about doing that:

-> make a copy of the current movable and scalable ROI
-> change attributes of that copy; fix size and position
-> add copy to the plot

  def saveROI(self):      
      copyROI = self._ROI   #make copy of user-draggable ROI
#      copyROI.setProperty("movable", False) #doesn't seem to work
      copyROI.setZValue(10)  # make sure ROI is drawn above image
      copyROI.translatable = False   #fix position
      copyROI.removeHandle(0)    #disable scaling
      self._Plot.addItem(copyROI)

However, this will overwrite the user-draggable ROI (self._ ROI) and only display the copy. I think the ROI object must have some index so basically it is overwritten by the copy?
To overcome this I could get all the relevant data from the user-ROI and build fixed ROI from that but it seems kinda ugly (lots of if statments to handle the different ROI shapes etc.). It would be much nicer to create a copy and just alter some attributes on the fly. Is this possible?

On a side note, could someone explain to me how one uses the .setProperty method correctly?

Thanks a lot, Chris

[Cho]

So I found out about Python variables just being pointers so I guess the problem lies in the line:

copyROI = self._ROI   #make copy of user-draggable ROI

However copy.copy or copy.deepcopy throws a bunch of errors that I don't quiet understand (I guess an instance of a class cannot be copied with all the arguments being real copies as well).

So I resorted to generating new ROIs from the ground up which I tried to circumvent in the first place. Now new problems arise...Here's a code snippet:

if self.ROI_comboBox.currentText()=="Rectangle":
 copyROI = pg.RectROI([self._ROIXPos, self._ROIYPos], [self._ROISizeX, self._ROISizeY],
           pen=pg.mkPen(color=self._ROIList_PenItems[index],width=1),removable=True)
elif self.ROI_comboBox.currentText()=="Circle":  
 copyROI = pg.CircleROI([self._ROIXPos, self._ROIYPos], [self._ROISizeX,
 self._ROISizeY],pen=pg.mkPen(color=self._ROIList_PenItems[index],width=1),removable=True)
       
       
        copyROI.setZValue(100)  # make sure ROI is drawn above image
        copyROI.translatable = False
        handle = copyROI.getHandles()
!!!!!!  copyROI.removeHandle(handle[0])     #this line throws an error that NoneType doesn't have a method removeItem
        handle[0].disconnectROI(copyROI)
        print("Get handles: ",copyROI.getHandles())
        print("Handle[0]: ",handle[0])
        print("type(copyROI): ",type(copyROI))
        self._P1.addItem(copyROI)  

So basically I create a ROI of type determined by a user selection widget (rectangle or circle). I can see the automatically created handle object (when creating a rect ROI) just fine. However when I try to remove it to effectively disable scaling it throws an error that an object of NoneType doesn't have a method of removeItem. It's strange because in the snippet I posted in the first post the method .removeHandle(0) works fine on the auto-created handle of a rect ROI object. Whats causing this?

I got a dirty workaround now which you can see in the above snippet namely I disconnect the handle from the ROI of interest. It thus becomes disabled and scaling becomes impossible. Just what I wanted however the handle is still visible which I would like to avoid.

Any help is greatly appreciated, Chris

[dew]

You have to add the roi to the image so that it can be identified as current scene.
Example:

self.imv.addItem(copyROI)
handles = copyROI.getHandles()
for index, item in enumerate(handles):
    copyROI.removeHandle(item)


where imv is the ImageView