Fix/bipolar center color

[hemanth5055]

📌 Description

This PR fixes the knob background color logic for parameters with ranges that span negative to positive values (e.g., -100 to 100).

• Previously, the knob background worked only for 0 → 100 ranges (green → red).

• For bipolar ranges like -100 → 100, the midpoint (0) should represent balance and display as green, while extremes (-100 and 100) should display as red.

• Added a gradient mapping for negative, zero, and positive values:

  • -100 → red
  • -75 → orange
  • 0 → green
  • +75 → orange
  • +100 → red

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✅ Related Issue

Closes #60

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📷 Screenshots

Before

Knob background incorrectly mapped 0 → green and 100 → red, but did not account for -100 → 100 ranges.

After

Knob background now correctly displays red at extremes, green at center, orange in between for bipolar ranges.

Screen.Recording.2025-10-01.at.5.48.09.PM.mov

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⚠️ Breaking Changes

• None. The fix only updates knob UI behavior for parameters with bipolar ranges.

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🔍 Testing Done

• Verified knob color behavior with 0 → 100 ranges (unchanged).
• Verified knob color behavior with -100 → 100 ranges (now correct).
• Manually tested with parameters like panning.

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ℹ️ Additional Notes

• Improves UI intuitiveness and clarity for parameters with bipolar ranges.
• Small but impactful UX improvement.

[lilyvanoekel]

could we detect this dynamically instead of hardcoding to panning params? I think we can use paramRange from params.ts

[lilyvanoekel]

We don't need orange as a specified colour, we can just rely on the blending between green and red. (I can see how that was confusing in the issue description, sorry about that!)

[lilyvanoekel]

@hemanth5055 thanks for this PR! I had a few small comments.

I also have a question about the video. It seems like the velocity knob also changes background colour?

[hemanth5055]

@hemanth5055 thanks for this PR! I had a few small comments.

I also have a question about the video. It seems like the velocity knob also changes background colour?

Hey @lilyvanoekel, thanks for the review .Yes, I noticed that the velocity knob background changes. I will investigate the cause and work on the issues you mentioned above.

[hemanth5055]

Hey @lilyvanoekel, I’ve updated the code according to your review and also fixed the issue where the velocity knob’s background was changing when adjusting the panning knob.

Screen.Recording.2025-10-01.at.10.46.59.PM.mov