I can use https://material.io/tools/color to generate attractive color palettes. The result is a set of eight colors.
Unfortunately, the ThemeData makes it difficult to build a theme from these eight values alone. There is a constructor that promises to derive sensible default values for missing arguments, however it doesn't derive everything from the primary and secondary colors.
Am I missing something here? Are there any Flutter tools for converting a material palette into a material theme?
Yes, In flutter, you can use MaterialColor for different color shades like Colors.blue[300].
Though ThemeData accepts Color Object as per its constructor but you can use MaterialColor with different color shades like Colors.blue[300] since its inherited from Color:
(Color -> ColorSwatch -> MaterialColor)
Recommendations:
you should not use it directly in ThemeData or anyplace where Color is needed since sometimes while building compiler raises the issue with a glitch of red error screen (I personally faced this issue).
For example:
final AppTheme = ThemeData(
primarySwatch: Colors.blue[300], //<- Not recommended
);
The right solution to this issue is :
final AppTheme = ThemeData(
primarySwatch: Colors.blue.shade300, //<- recommended
);