TrailPointer¶

Overview¶

Points to a specific node (with a trail), and whether it is conceptually before or after the node.

There are two orderings: - rendering order: the order that node selves would be rendered, matching the Trail implicit order - nesting order: the order in depth first with entering a node being "before" and exiting a node being "after"

TODO: more seamless handling of the orders. or just exclusively use the nesting order https://github.com/phetsims/scenery/issues/1581

@author Jonathan Olson <jonathan.olson@colorado.edu>

Class TrailPointer¶

import { TrailPointer } from 'scenerystack/scenery';

Constructor¶

new TrailPointer( trail : Trail, isBefore : boolean )¶

Instance Methods¶

isActive() : this is ActiveTrailPointer¶

copy() : TrailPointer¶

setBefore( isBefore : boolean )¶

getRenderSwappedPointer() : TrailPointer | null¶

Return the equivalent pointer that swaps before and after (may return null if it doesn't exist)

getRenderBeforePointer() : TrailPointer | null¶

getRenderAfterPointer() : TrailPointer | null¶

compareRender( other : TrailPointer ) : number¶

In the render order, will return 0 if the pointers are equivalent, -1 if this pointer is before the other pointer, and 1 if this pointer is after the other pointer.

compareNested( other : TrailPointer ) : number¶

Like compareRender, but for the nested (depth-first) order

TODO: optimization? https://github.com/phetsims/scenery/issues/1581

equalsRender( other : TrailPointer ) : boolean¶

equalsNested( other : TrailPointer ) : boolean¶

hasTrail() : boolean¶

Will return false if this pointer has gone off of the beginning or end of the tree (will be marked with isAfter or isBefore though)

nestedForwards() : this | null¶

Moves this pointer forwards one step in the nested order

TODO: refactor with "Side"-like handling https://github.com/phetsims/scenery/issues/1581

nestedBackwards() : this | null¶

Moves this pointer backwards one step in the nested order

eachNodeBetween( other : TrailPointer, callback : ( node: Node ) => void )¶

Treats the pointer as render-ordered (includes the start pointer 'before' if applicable, excludes the end pointer 'before' if applicable

eachTrailBetween( other : TrailPointer, callback : TrailCallback )¶

Treats the pointer as render-ordered (includes the start pointer 'before' if applicable, excludes the end pointer 'before' if applicable

depthFirstUntil( other : TrailPointer, callback : ActiveTrailPointerCallback, excludeEndpoints : boolean )¶

Recursively (depth-first) iterates over all pointers between this pointer and 'other', calling callback( pointer ) for each pointer. If excludeEndpoints is truthy, the callback will not be called if pointer is equivalent to this pointer or 'other'.

If the callback returns a truthy value, the subtree for the current pointer will be skipped (applies only to before-pointers)

toString() : string¶

Returns a string form of this object

Instance Properties¶

trail : Trail | null¶

isBefore : boolean¶

isAfter : boolean¶

Static Methods¶

compareNested( trailA : Trail, isBeforeA : boolean, trailB : Trail, isBeforeB : boolean ) : number¶

Same as new TrailPointer( trailA, isBeforeA ).compareNested( new TrailPointer( trailB, isBeforeB ) )

Source Code¶

See the source for TrailPointer.ts in the scenery repository.