onError property
A color that is clearly legible when drawn on error color.
To ensure that an app is accessible, a contrast ratio of 4.5:1 for error and onError is recommended. See www.w3.org/TR/UNDERSTANDING-WCAG20/visual-audio-contrast-contrast.html.
If null, the on color is derived from the brightness of the error color, and will be be black if it is light and white if it is dark.
Implementation
final Color? onError;