Ratio is a graphical colour-contrast validation tool intended for designers, developers and anyone checking an interface for accessibility problems. It applies the contrast calculations defined by the Web Content Accessibility Guidelines rather than relying on subjective visual judgement.
The program focuses on three specific WCAG success criteria. These cover the contrast of normal text, the visibility of non-text interface components and the appearance of keyboard focus indicators. This makes Ratio useful when choosing foreground and background colours for websites, applications and other interfaces where sufficient visual distinction matters.
This is free and open source software.
Key Features
- Calculate contrast between foreground and background colours.
- Validate colour combinations against WCAG requirements.
- Checks WCAG Success Criterion 1.4.3 for text contrast.
- Checks WCAG Success Criterion 1.4.11 for non-text interface elements.
- Checks WCAG Success Criterion 2.4.13 for focus appearance.
- Provides immediate feedback while experimenting with colour combinations.
- Useful for checking application and website interface designs.
- Focused graphical interface without broader design-suite complexity.
- Helps identify combinations which may be difficult for visually impaired users to distinguish.
Website: codeberg.org/markwyner/ratio-for-linux
Support:
Developer: Mark Wyner
License: GNU General Public License v3.0
Ratio is written in Python. Learn Python with our recommended free books and free tutorials.
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