Add threshold filter algorithm: hide/remove pixels below user-specified value in preview #10
Description
Summary
Add a new algorithm option that allows users to provide a threshold value; pixels with values below that threshold are removed/zeroed in the preview histogram (JSROOT) and optionally in the encoded result. This provides a simple way to mask noise/low-intensity background in images.
User story
As a user, I want to apply a threshold filter that sets pixels below a chosen value to zero (or marks them as masked) so I can better inspect high-intensity features in the preview and exported result.
Requirements
- UI control to set threshold value (numeric input / slider) and a checkbox to choose between "zero out" or "mask" (masking could show as transparent or a specific color).
- Preview should update immediately to show the effect.
Acceptance criteria
- Users can set a threshold and apply the filter; preview updates to reflect pixels below the threshold being removed/zeroed.