Web UI forces broken `ENABLED_WITH_HISTOGRAM` on DSLRs and fails to detect config changes for saving

[enzolutions]

Environment

• Server Host: Raspberry Pi
• OS: Raspbian (connecting via Wi-Fi)
• INDIGO Server Version: 2.0-352
• Camera: Nikon D5200 (DSLR connected via USB)
• Client: Web Browser Interface (accessing port 7624)

Description

When attempting to use an attached DSLR (Nikon D5200) via the INDIGO Web interface, image capture fails completely due to the UI aggressively enforcing a broken configuration setting.

Despite configuring the camera correctly in the Control Panel (e.g., CCD_UPLOAD_MODE = CLIENT or LOCAL, and CCD_PREVIEW = ENABLED), opening the "Imager" tab (/imager.html) or attempting to take an exposure immediately and silently reverts the preview setting to ENABLED_WITH_HISTOGRAM. This setting appears to be broken for this DSLR model, causing the image processing pipeline to fail silently (no image in UI, no file saved to disk).

Crucially, the Control Panel UI (/ctrl.html) seems unable to manage this setting correctly. If the setting has reverted to ENABLED_WITH_HISTOGRAM, manually clicking back to the correct middle option ("Enabled") does not cause the "Configuration control" section (Main -> Configuration control) to turn red. The UI fails to register this parameter change, making it impossible to save the corrected configuration normally via the interface's "Save" button.

This seems closely related to, or a confirmation/extension of, existing issue #582.

Steps to Reproduce

1. Start INDIGO Server with Nikon D5200 connected via USB.
2. Open the Web UI Control Panel (/ctrl.html).
3. Navigate to the camera settings -> "Enable preview".
4. Observe that the setting might be on "Enabled with histogram" (due to previous interaction with the Imager tab).
5. Click the middle button to change it to "Enabled" (the correct setting for DSLRs).
6. Observation: Look up at the "Main -> Configuration control" section header. It does not turn red, indicating the UI has not detected this change as something that needs saving.
7. Navigate to the "Imager" tab (/imager.html) and attempt a capture. It fails.

Analysis & Debugging Evidence (SSH)

We have confirmed via SSH that the Web UI is overwriting settings behind the scenes.

1. Proof of correct setup via SSH (Web UI closed):
We configure the camera correctly via CLI, forcing ENABLED (without histogram).

indigo_prop_tool set "Nikon D5200.CCD_UPLOAD_MODE.CLIENT=ON;Nikon D5200.CCD_PREVIEW.ENABLED=ON"

**2. Proof of Web UI interference: **
Immediately after running the above, opening or refreshing the imager.html tab in the browser causes the setting to change automatically in the backend:

indigo_prop_tool list "Nikon D5200" | grep "CCD_PREVIEW"
# Output shows it reverted automatically:
Nikon D5200.CCD_PREVIEW.ENABLED = OFF
Nikon D5200.CCD_PREVIEW.ENABLED_WITH_HISTOGRAM = ON

**3. Confirmation that hardware works (Workaround): **
If we close all browser instances and operate purely via SSH, forcing the correct capture mode and saving locally, the hardware works perfectly and images are saved to disk.

Conclusion

The hardware and server backend are functional. The issue is isolated to the Web UI logic, which incorrectly forces ENABLED_WITH_HISTOGRAM and simultaneously fails to detect user attempts to correct this setting in the Control Panel, preventing normal saving of the working configuration.

Offer of Help

I am a programmer and am willing to help investigate or fix this UI behavior if provided with some guidance on where to look in the codebase.

[earthonlinegame]

I've fix this issue and tested with Canon, Nikon and Sony cameras. Later will post a PR.