Contrast / viewability improvements for standard/reader mode: dark text, halftone images

[dredmorbius]

On my Onyx BOOX Max Lumi, at the highest "Regal" display quality, I consistently find:

• I need to increase dark contrast to 40--60 to achieve sufficiently dark text. (The full range is 0--100.)
• As a consequence images are overly dark.
• In "Regal" mode, images are limited to a 16-shade greyscale pallette, further reducing overall quality.

The BOOX has per-app display settings with the ability to tune darkness, a "watermark" threshold (light shades not displayed), as well as an overall display mode that seems to be based on the underlying e-ink display itself.

Toggling between "Regal" and "Speed" modes, I notice that images switch from being rendered as fully-gradated bitmaps to halftoned images. This is very nearly always an improvement in overall quality and viewability. Text clarity is reduced somewhat. I much prefer "Regal" mode in EInkBrow for the clarity of text rendering, and that works beautifully when using paginated navigationt through the document. But that leaves me fighting for appropriate contrast between text and images.

The underlying problem is of far too many websites specifying a text/background palette that's not either a pure black-on-white or white-on-black. These render as mudded-out greys on e-ink.

Request:

• Provide a darkness control for text that applies only to text and not other visual elements. (This is effectively a CSS rule or rules applying to all text elements.) The key problem is text on a dark background, which can be difficult to detect or correct. That's already problematic on e-ink devices.
• Filter all images through a halftone filter, or alternatively an improved dithering filter. Halftone seems to be possible using CSS, see this StackOverflow: https://stackoverflow.com/questions/62497837/how-to-create-halftone-effect-in-images-with-pure-css#62500405 I'm not finding dither support in CSS.

There may also be hooks to engage with the e-ink display itself directly, I'm unfamiliar with specs / APIs.

This is a nice-to-have, not a necessary feature. It would improve render clarity greatly however.