computeChildMainAxisPosition abstract method
- RenderSliver child,
- double parentMainAxisPosition
parentMainAxisPosition into the child's coordinate system.
parentMainAxisPosition is a distance from the top edge (for vertical
viewports) or left edge (for horizontal viewports) of the viewport bounds.
This describes a line, perpendicular to the viewport's main axis, heretofore
known as the target line.
The child's coordinate system's origin in the main axis is at the leading edge of the given child, as given by the child's SliverConstraints.axisDirection and SliverConstraints.growthDirection.
This method returns the distance from the leading edge of the given child to the target line described above.
parentMainAxisPosition is not from the leading edge of the
viewport, it's always the top or left edge.)
@protected double computeChildMainAxisPosition(RenderSliver child, double parentMainAxisPosition);