Is it possible to customize the contrast threshold?

[marcodevsquad]

In bootstrap 4 we have a variable called $yiq-contrasted-threshold: were has a value of 150 by default and this variable ajusts the threshold to decide if the color should be black or white in components. Is there something similar to this?

I thought something like this:

invert('#d9534f', { threshold: 155 }); // #ffffff

And congrats for this awesome project! Thank you very much!

[onury]

Thanks.

The default threshold of this library is gathered from the formula given for contrast in the W3C Recommendations. There is an inner constant for luminance threshold but currently there is no option to customize this with exposed API.

The threshold value is in a scale of 0.0 (lowest) to 1.0 (highest). The default threshold is calculated with Math.sqrt(1.05 * 0.05) - 0.05 which is approx. ~0.179. I don't know the scale of that bootstrap variable. You would need to convert it to 0.0-1.0 scale or vice-versa.

I'll mark this to be implemented.

[onury]

Notes for implementation:

• Add optional property threshold?: number to BlackWhite interface.
• Expose default threshold calculated value as defaultThreshold property. Remove BW_THRESHOLD constant.
• Update related methods.

[marcodevsquad]

Thank you for your fast reply! Just to complement, this feature IMHO will make your package perfect and complete!

Congratulations for this project!! Keep on moving! 😉 👍

[onury]

Added this in v2.0.0 (unreleased).
Hope this works for you.
I'll release as soon as #17 fix is confirmed.

[onury]

released.