What an action would do to the canvas, ready to paint.
A forecast leaves the graph exactly as it is — nothing dims, nothing moves — and
marks only what the action would change: what would go, what would be hidden, and
an outline of what would come back. That is the difference between a forecast and
GraphRenderer.emphasiseElements, which reads a set out of the canvas by
receding everything else.
GraphHistoryLike.preview hands one over ready-made, which is how hovering
a history row shows what the click would do.
What an action would do to the canvas, ready to paint.
A forecast leaves the graph exactly as it is — nothing dims, nothing moves — and marks only what the action would change: what would go, what would be hidden, and an outline of what would come back. That is the difference between a forecast and GraphRenderer.emphasiseElements, which reads a set out of the canvas by receding everything else.
GraphHistoryLike.preview hands one over ready-made, which is how hovering a history row shows what the click would do.