focal property
final
The focal point of the gradient. If specified, the gradient will appear to be focused along the vector from center to focal.
See center for a description of how the coordinates are mapped.
If this value is specified and focalRadius > 0.0, care should be taken to ensure that either this value or center will not both resolve to Offset.zero, which would fail to create a valid gradient.
Implementation
final AlignmentGeometry? focal;