Some good practices when it comes to charts and data visualizations: use high contrast colors, avoid problematic pairings (red-green, blue-yellow), use symbols as well as colors...
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You can enable the possibility of providing assets for different appearances including light/dark modes and high contrast. As we've seen, that's valid for colors, but you can do the same for images too! https://x.com/dadederk/status/1594724075590619138?s=20&t=XJrlJiGSCTR9sJC7XPZPjA
Manual testing is crucial. And therefore, reducing friction to let you start your testing process can be a huge help. Selecting some accessibility shortcuts will do that, putting most of iOS' accessibility features at a triple-click of a button.
If, for some reason, you are creating a button from scratch, instead of relying on UIButton (perhaps you are adding a fancy micro interaction animation?), take into account that you’ll need to configure the button accessibility trait.
