offAxisFraction property

double offAxisFraction

How much the wheel is horizontally off-center, as a fraction of its width. This property creates the visual effect of looking at a vertical wheel from its side where its vanishing points at the edge curves to one side instead of looking at the wheel head-on.

The value is horizontal distance between the wheel's center and the vertical vanishing line at the edges of the wheel, represented as a fraction of the wheel's width.

The value 0.0 means the wheel is looked at head-on and its vanishing line runs through the center of the wheel. Negative values means moving the wheel to the left of the observer, thus the edges curve to the right. Positive values means moving the wheel to the right of the observer, thus the edges curve to the left.

The visual effect causes the wheel's edges to curve rather than moving the center. So a value of 0.5 means the edges' vanishing line will touch the wheel's size's left edge.

Defaults to 0.0, which means looking at the wheel head-on. The visual effect can be unaesthetic if this value is too far from the range -0.5, 0.5.

Implementation 

/// This property creates the visual effect of looking at a vertical wheel from
/// its side where its vanishing points at the edge curves to one side instead
/// of looking at the wheel head-on.
///
/// The value is horizontal distance between the wheel's center and the vertical
/// vanishing line at the edges of the wheel, represented as a fraction of the
/// wheel's width.
///
/// The value `0.0` means the wheel is looked at head-on and its vanishing
/// line runs through the center of the wheel. Negative values means moving
/// the wheel to the left of the observer, thus the edges curve to the right.
/// Positive values means moving the wheel to the right of the observer,
/// thus the edges curve to the left.
///
/// The visual effect causes the wheel's edges to curve rather than moving
/// the center. So a value of `0.5` means the edges' vanishing line will touch
/// the wheel's size's left edge.
///
/// Defaults to 0.0, which means looking at the wheel head-on.
/// The visual effect can be unaesthetic if this value is too far from the
/// range [-0.5, 0.5].
/// {@endtemplate}
double get offAxisFraction => _offAxisFraction;
void offAxisFraction= (double value)

Implementation 

set offAxisFraction(double value) {
  assert(value != null);
  if (value == _offAxisFraction)
    return;
  _offAxisFraction = value;
  markNeedsPaint();
}