r method
Scale value uniformly using the minimum of width/height ratio.
Useful for elements that should scale uniformly regardless of aspect ratio (icons, avatars, border radius).
Implementation
double r(double value) {
final widthRatio = screenWidth / _config.designSize.width;
final heightRatio = screenHeight / _config.designSize.height;
return value * (widthRatio < heightRatio ? widthRatio : heightRatio);
}