BrushLabels significantly decrease editor performance

[longapple]

Hello team,

Recently I found an issue with brushlabels, which is that a few brushlabels can decrease the annotation performance. The operations on editor is very laggy. Submitting/Updating takes more than 5 seconds and some times the how browser tab freezes.

Here is how to reproduce it:

Install latest version (1.16.0) with pip: pip install label-studio
Create a project with only one task (image). Define label config with a very simple BrushLabel:

<View>

<View>
  <View>
    <View>
      <View>Choose Label</View>
      <View>
        <BrushLabels name="tag" toName="image">
        	<Label value="light" background="#FFA39E"/>
        </BrushLabels>
      </View>
    </View>

  </View>
  <View>
    <Image name="image" value="$image" zoom="true" zoomControl="true"/>
  </View>
</View>
</View>

Now start to annotate, add 5 or 6 annotations. Then click "Submit", the browser freezes for 10 seconds and then finally the task gets submitted.

[heidi-humansignal]

Hello,

Thank you for contacting Label Studio,

Our engineering team is actively working on further optimizations to reduce the processing overhead of brush annotations. In the meantime, if you could share any additional details (such as browser console logs when the freeze happens), it would help us diagnose the issue further

Thank you!

Comment by Oussama Assili
Workflow Run

[longapple]

Hello,

Thanks for your reply. The browser console doesn't have any logs when this happens.

I dig a little bit more on this and found out all the slowness is on this call:

serializeAnnotation()

For RectangleLabels and PolygonLabels, this call just returns immediately. For BrushLabels, it's very slow.

Hope this helps.