# Label outline rendering in VTK.js's ImageResliceMapper

**URL:** https://discourse.vtk.org/t/label-outline-rendering-in-vtk-jss-imagereslicemapper/16224
**Category:** Web
**Created:** [January 12, 2026, 3:42pm UTC](https://discourse.vtk.org/t/label-outline-rendering-in-vtk-jss-imagereslicemapper/16224 "2026-01-12T15:42:12Z")
**Posts on this page:** 5
**Page:** 1

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### Author: ![PaulHax](https://discourse.vtk.org/user_avatar/discourse.vtk.org/paulhax/32/2748_2.png) [@PaulHax](https://discourse.vtk.org/u/PaulHax)
#### Post date: [January 12, 2026, 3:42pm UTC](https://discourse.vtk.org/t/label-outline-rendering-in-vtk-jss-imagereslicemapper/16224/1 "2026-01-12T15:42:12Z")

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I’ve added label outline rendering for the oblique slicing ImageResliceMapper. This is based on the label outline rendering work already in ImageSliceMapper.

This is not on master - it’s a starting point if anyone is interested in this feature.

> <https://github.com/PaulHax/vtk-js/pull/10>
>
> This brings ImageResliceMapper closer to feature parity with ImageSliceMapper by… adding the label outline effect for oblique slicing.
> 
> \- Add multi-input compositing for background + labelmap rendering                                                 
> \- Add label outline effect with configurable thickness and opacity per labelmap                                   
> \- Support different resolution labelmaps                                                                          
> \- Add two new examples: ResliceCursorWidgetLabelmap and ImageResliceMapperLabelOutline 
> 
> ImageResliceMapperLabelOutline
> \<img width="2560" height="1528" alt="image" src="https://github.com/user-attachments/assets/9038b402-0729-4b44-a4f0-6552a3c354f6" /\>
> 
> ResliceCursorWidgetLabelmap
> \<img width="2560" height="1528" alt="image" src="https://github.com/user-attachments/assets/046787ca-154a-4e15-b06a-3c290378110b" /\>

 ![image](https://discourse.vtk.org/uploads/default/original/2X/0/03288a9e13880988c82d556a9317155652e8af0c.jpeg)

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### Author: ![Alireza](https://discourse.vtk.org/user_avatar/discourse.vtk.org/alireza/32/6230_2.png) [@Alireza](https://discourse.vtk.org/u/Alireza)
#### Post date: [February 4, 2026, 2:34pm UTC](https://discourse.vtk.org/t/label-outline-rendering-in-vtk-jss-imagereslicemapper/16224/2 "2026-02-04T14:34:11Z")

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I would like to help to get this merged. What can i do?

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### Author: ![PaulHax](https://discourse.vtk.org/user_avatar/discourse.vtk.org/paulhax/32/2748_2.png) [@PaulHax](https://discourse.vtk.org/u/PaulHax)
#### Post date: [February 4, 2026, 4:21pm UTC](https://discourse.vtk.org/t/label-outline-rendering-in-vtk-jss-imagereslicemapper/16224/3 "2026-02-04T16:21:11Z")

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Super. Feel free to do as you wish with the code. Feature works well in isolation, but it touches a few other things and I have not explored if that breaks other features.

And thanks for your intial outline work on which this is based. Would not have happened without that. =)

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### Author: ![Alireza](https://discourse.vtk.org/user_avatar/discourse.vtk.org/alireza/32/6230_2.png) [@Alireza](https://discourse.vtk.org/u/Alireza)
#### Post date: [February 9, 2026, 10:02pm UTC](https://discourse.vtk.org/t/label-outline-rendering-in-vtk-jss-imagereslicemapper/16224/4 "2026-02-09T22:02:37Z")

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Would you mind creating a PR to vtk.js then i work there?

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### Author: ![PaulHax](https://discourse.vtk.org/user_avatar/discourse.vtk.org/paulhax/32/2748_2.png) [@PaulHax](https://discourse.vtk.org/u/PaulHax)
#### Post date: [February 10, 2026, 12:53am UTC](https://discourse.vtk.org/t/label-outline-rendering-in-vtk-jss-imagereslicemapper/16224/5 "2026-02-10T00:53:17Z")

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💁 [Reslice labelmap by PaulHax · Pull Request #3406 · Kitware/vtk-js · GitHub](https://github.com/Kitware/vtk-js/pull/3406)