Standard names for “stacked” versus “hanging” layered graph drawing algorithms?

Question

Here are two different ways of drawing the same hierarchy. Notice that in the "stacked" layout, nodes are always one layer higher than their highest "child" node. ( Important: See edit at bottom of question for another example)

Do these two types of layered drawing methods have specific names? I'm trying to find existing algorithms for the "stacked" one, but can't seem to surface any info because I don't know what it's called.

If they don't have names to distinguish them because they rely on the same algorithm, are there well known sets of parameters for attaining the "stacked" version of the graph with existing algorithms? Thanks!

Edit: Although the above graphs are strict " trees ", the algorithm I'm looking for should be able to handle cases where nodes have more than one parent, and cases where there is more than one path from root to leaf. Here's an example , and here's another .

Edit2: In case it's useful to anyone, a hacky (and slow) force-directed approach with pre-computed node layers (y-axis contraints) seems to work all right. Here's what it looks like . That example uses cytoscape.js and cola.js, and it's upside down. It's not at all a solution to this question so I'm just putting this here as an edit.

(SO wouldn't let me submit the JSBin link without a code block...)

Answer 1

I don't know of any specific names for the above. It looks like the layering algorithm in both cases is the longest path algorithm that minimizes height but essentially ignores width. If you layer the graph from the bottom-up and the graph has many sinks (vertices with zero out-degree) then you will get a wide bottom layer (a "stacked" layout?). If you layer the graph from the top-down and it has many sources (vertices with zero in-degree) then you will get a wide top layer (a "hanging" layout?).