stac-extensions/classification

Supporting hints for alpha channel transparency?

Opened this issue · 1 comments

tylere commented

There currently exists a color_hint property that hints at how the class should be visualized, and is required to be a 6 character hex code ("pattern": "^([0-9A-Fa-f]{6})$") for an RGB color. This does not allow for hinting on visualization alpha channel transparency for the color.

Ideas for including support for alpha channel hints:

  1. Expand the schema for the color_hint property to allow for optionally specifying an alpha channel as a RGBA code. ("pattern": "^([0-9A-Fa-f]{6})$|^([0-9A-Fa-f]{8})$"). This is my current preferred option.

  2. Add an optional sibling property alpha_hint that specifies the alpha channel ("pattern": "^([0-9A-Fa-f]{2})$")

m-mohr commented

I think I also prefer option 1. Happy to review PRs.