PackStraighten doesn't work well

GoJS
1

Hi,

I’m using AlignedLayeredDigraphLayout as the main layout and as the layout of my groups.
I’m dealing with big topologies so it’s very importent that the line will be straighten if possible.

here is an example for lines that are almost straight :(

image
image.png674×678 49.3 KB

layout: $(AlignedLayeredDigraphLayout, {
columnSpacing: 15,
layerSpacing: 100,
linkSpacing: 150,
layeringOption: go.LayeredDigraphLayout.LayerOptimalLinkLength,
aggressiveOption: go.LayeredDigraphLayout.AggressiveMore,
initializeOption: go.LayeredDigraphLayout.InitDepthFirstIn,
//packOption: go.LayeredDigraphLayout.PackAll,
packOption: go.LayeredDigraphLayout.PackStraighten,
setsPortSpots: false
})

Thanks!

2

“Straightening” within the context of LayeredDigraphLayout refers to putting nodes in the same column. It does not refer to making sure the link routes are straight, although that is usually the case.

In order for the link routes to be straight, it helps that the nodes are of the same breadth (height in this case), or at least in multiples of the LayeredDigraphLayout.columnSpacing.

What I suspect is happening is that the Group heights and Y positions are not multiples of the columnSpacing, and that is causing nodes to be shifted vertically with respect to each other when comparing nodes in different groups. So if you can maybe decrease the Placeholder.padding Margin.top a bit, that might help in that particular case.

More generally you’ll need to see if you can get the vertical distance between the top of the group and the top of the top member node to be a multiple of the columnSpacing, that might help. But it’s not guaranteed in any case.