Add SPICE image rendering with full PC WCS support

[SalimHachemaoui]

No description provided.

[mudhoney]

Hi @SalimHachemaoui

I made couple of tests with rendering of SPICE in our web frontend, I am seeing SPICE images kind of stretched.
I m attaching the screenshot, would you check if there is problem with the rendering?

[SalimHachemaoui]

Hi @mudhoney ,
You are right. I reproduced the issue locally and confirmed that the interactive SPICE rendering works correctly, but the generated screenshot does not yet apply the full SPICE WCS geometry.
The screenshot generation uses a separate server-side rendering path that still assumes a single scalar image scale. As a result, the anisotropic X/Y scales and PC matrix are not applied, which causes the stretched vertical image shown in your screenshot.
I am working on this remaining part and will update the PR once screenshot generation renders SPICE consistently with the interactive viewport.
Thanks for identifying and testing this.

[mudhoney]

Hi @SalimHachemaoui

Thank you for following up and effort to fix the problem.

I am able to generate the same problem in interactive frontend too also for the screenshots, You can follow this link https://necdet.helioviewer.org/load/d7c388a9aa8efc0812142f2bf7418cf3396501c8ddcb97d663c69f31595ea4e5 to see the problem.

[SalimHachemaoui]

Hi @mudhoney ,
Thank you for the link. I understand now that the issue is reproducible in both the interactive frontend and the server-generated screenshots on your deployment.
My local interactive test was using a locally modified version of the frontend and @helioviewer/sun, which explains why SPICE appeared correctly there. Those frontend changes are not included in the current API PR.
I am now checking both rendering paths separately:
the client-side WCS transformation used by the interactive frontend;
the server-side composite renderer used for screenshots and movies.
I will avoid pushing the current experimental screenshot fix until both paths use the same SPICE WCS conventions and produce consistent results. Thank you for providing the reproducible state.

[dgarciabriseno]

Thank you Salim, Our environment often requires changes made to the back end and front end simultaneously. It is a pain point, honestly. We appreciate these PRs, it will be great to have this data supported in the web client.

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On August 18, 2026 11:38:59 AM EDT, salim HACHEMAOUI ***@***.***> wrote: SalimHachemaoui left a comment (Helioviewer-Project/api#513) Hi @mudhoney , Thank you for the link. I understand now that the issue is reproducible in both the interactive frontend and the server-generated screenshots on your deployment. My local interactive test was using a locally modified version of the frontend and @helioviewer/sun, which explains why SPICE appeared correctly there. Those frontend changes are not included in the current API PR. I am now checking both rendering paths separately: the client-side WCS transformation used by the interactive frontend; the server-side composite renderer used for screenshots and movies. I will avoid pushing the current experimental screenshot fix until both paths use the same SPICE WCS conventions and produce consistent results. Thank you for providing the reproducible state. <img width="1916" height="972" alt="image" src="https://github.com/user-attachments/assets/cd996903-6af9-44ae-afe6-da1355fad70d" /> -- Reply to this email directly or view it on GitHub: #513 (comment) You are receiving this because you are subscribed to this thread. Message ID: ***@***.***>