APCA™ is the Accessible Perceptual Contrast Algorithm, a new way to predict contrast for text and non-text for content on self-illuminated displays. This repository is for the documentation, for issue tracking, and for the discussion forum.
The correct code to use is apca-w3 which is in its own satellite repository, and is also available at npm i apca-w3 That is the only code that should be used for any development purposes.
The draft independent APCA Readability Criterion is up as a work in progress, still sections to be added and/or adjusted.
For comments or questions on the guidelines, use the ARC forum, that is where we discuss the draft standards & guidelines, and discuss legal & conformance issues.
For comments or questions on theory, math, or the APCA algorithm itself, use the SAPC-APCA forum here, please post all comments, questions, or discussions regarding theory, math, code, third-party tools,third-party tools, and so forth, here and not in the satellite repositories, so they can be tracked and resolved.
- Main Readme Doc This page includes the math, code walkthroughs and links for developer related goodies. If you'd like to dive into the deep end, this is a good start.
These are intended for end users, and those interested in a plain language overview without a lot of the math & theory.
- Why APCA? A basic overview
- APCA in a nutshell The minimum user guide
- APCA FAQ
Maths! Vision Science! Photons on Parade!
- The base APCA-W3 formula in LaTeX math for your viewing and calculating pleasure.
- Regarding Exponents Is delta-gamma some kinda frat house? Nope... It's math.
- Standard Observer Model The setting for a mathematical eyeball.
- Visual Contrast Draft Whitepaper Almost as tasty as a draft beer!
APCA™ Linktree
Curated link collection—an ideal starting point.
The main catalog of related articles, peer reviews, repositories, white papers, and more!
Myndex Research on Twitter
- Why APCA: A brief plain language overview of APCA and readability contrast.
- APCA in a Nutshell: Quick overview of levels, use cases, and font sizing.
- APCA Main Documentation (READ ME): The repo basic readme file for an overview and quickstart.
- APCA Documentation Index: An index of relevant APCA documentation.
- APCA Formula 0.9.98g4g: The repo basic readme file for an overview and quickstart.
- Repo List: A list of specific versions of APCA, Bridge PCA, and support files.
- Standard Observer Model: Draft Standard Observer.
- Important Change Notices: General Change History (see individual repos for specifics)
- Regarding Exponents: Notes on the exponents used in APCA.
- Accessibility Statement: A statement for beta testers and early adopters to use place on sites using APCA
- APCA Minimum Compliance for Developers: Standards for what can be called APCA™.
- APCA FAQ: Just starting, so few QA yet.
You are here 🔽 this index page is served at the github repo.
Over there is the APCA W3 version, and it's the same as the published npm package "apca-w3".
The BridgePCA is backwards compatible with WCAG 2, and it's the same as the published npm package "bridge-pca".
ColorParsley is a micro library for auto parsing color strings of all kinds, also on npm.
SeeStars is a micro library for creating CIE Lstar
DeltaPhiStar is an ultra simple general purpose contrast equation.
The canonical demo tool at Myndex
Try out the Bridge PCA tool at Myndex
Color insensitive vision simulation (aka colorblind). Includes deuteranopia, protanopia, tritanopia, and blue cone monochromacy/achromatopsia.
IRT is a California nonprofit, dedicated to developing tecnologies to improve visual accessibility for all, and home to the APCA Readability Criterion.
The APCA base color-pair formula, in math notation. 0.0.98G-4g
