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