Edge Style For Tree - cytoscape.js

I would like to have edges that are straight with right angles, similar to the family tree layout mentioned here: Styling edges in Cytoscape.js for a Family Tree
I've also attached an image showing what I would like to achieve.
In the link above they mention hyperedges, and changing the curve-style to "segments". I've done that, but there are only 2 segments and they do not form a right angle. There are some attributes that can be set for the segments, but I have not figured out how to make them work. Any help would be appreciated.

You have to calculate the points where the lines should be bent and set the segment style properties appropriately.
If you want an alternative way of specifying bent edges, you could investigate zigzag edges: https://github.com/cytoscape/cytoscape.js/issues/882

Related

Cytoscape Dagre shows connected Children when there are multiple children

I am using Cytoscape Dagre extension to show hierarchical graph from left to right.
It has 14 children and one parent 1 and main parent. All children are connected to parent 1 but whenever I use draw a graph using dagre extension, it seems like children are connected between each other. They do not have any edges between them but Dagre still shows that. Is Cytoscape with Dagre capable of showing hierarchical graphs with multiple children?
Here is the stackblitz example: https://stackblitz.com/edit/dagre-childrenconnected
Your edges overlap with your child nodes, that is not a dagre specific problem, your cytoscape-stylesheet is just missing some parameters. With taxi edges, the important thing to understand is, that your edges follow style rules like the layout algorithm you use. For layouts, you use the layout option to specify how the layout should place the nodes. The edges are styled via the stylesheet and they all have some options to play around with.
In your case, you should take a look at this section in the docs. There you can find options like the taxi-direction:
"taxi-direction": "rightward",
With this option, your edges will fit your layout a bit more. In your case, you didn't specify a direction, so taxi edges use the auto option as a default value, which automatically uses vertical or horizontal starting directions, based on whether the vertical or horizontal distance is largest. In your case, the vertical ones triggered resulting in overlapping nodes.

Cytoscape with Haystack or Bezier Layout: How to Shorten Edge Length

I am new to Cytoscape, and I have a working graph, but my nodes are very far apart. While I realize Cytoscape generates everything dynamically, it seems like it should be possible to say "use half as much space between nodes".
This demo:
http://js.cytoscape.org/demos/2ebdc40f1c2540de6cf0
seems to show that you can dynamically change the lengths of edges. However, when I look at the source code (https://gist.github.com/maxkfranz/2ebdc40f1c2540de6cf0), I can't figure out how it works.
It seems like the demo is passing a edgeLength option to makeLayout, but the Cytoscape documentation doesn't even mention edgeLength as a valid option.
Can anyone more experienced with Cytoscape point me to how I can shorten the edges between my nodes?
Each layout is different, and the combination of values you use depends on what effect you're trying to create.
Force-directed layouts usually have a weight that affects edge length by spring forces.
In general, the bounding box can affect the length.
Some layouts have spacing adjustment multipliers.
Some layouts have other, miscellaneous options that affect edge length.
You have to look at the options for the layout you're interested in and experiment with them to get the effect you're looking for. That holds true for every layout for every graph theory lib, Cytoscape included.

Setting control points for Cytoscape edges?

I'm trying to build a descending graph in Cytoscape. I've got the majority done quite well, but now I'm stuck on the edge types. I'd like to use something like the 'segments' curve-style, where my edges have points.
However, instead of being zig-zags, I would like the edges to be constrained to horizontal/vertical lines.
My graph is pretty constrained and the user cannot manipulate the positions. I would like the edges to start at the 'parent' element, go straight down a set amount, then hit a point, turn, head horizontally to the same X as the child, then straight down to the child element.
Right now, the lines go straight, and I can add segments easily, but they aren't constrained and are based on percentages that I won't have access to without doing a bunch of math, which I guess isn't terrible.
Current:
Desired:
If you want specific absolute positions on segments edges, you'll need to convert the absolute co-ordinates to the relative co-ordinates that you specify for segments edges.
If you want a different type of edges for your usecase, feel free to propose it in the issue tracker.

What's this kind of graph called?

I have a kind a graph, I found it while googling "tree graph" though it doesn't look like a normal tree-graph. So I was wondering, is it also just called a "tree-graph" or has it a more specific name? I want to look up more info about them, though can't really search for it without a proper name.
Thanks a lot!
PS. I'm not sure if this is the correct place to ask this, if it's not, please direct me to the proper place. Thanks.
Google calls it a Treemap and provides several examples and an ontology. They define the treemap as follows:
A visual representation of a data tree, where each node can have zero or more children, and one parent (except for the root, which has no parents). Each node is displayed as a rectangle, sized and colored according to values that you assign. Sizes and colors are valued relative to all other nodes in the graph.
Source: Google Developers / Google Charts
It's typically called a "heat map" or "heat chart".
That's a Treemap:
Treemaps display hierarchical (tree-structured) data as a set of
nested rectangles. Each branch of the tree is given a rectangle, which
is then tiled with smaller rectangles representing sub-branches. A
leaf node's rectangle has an area proportional to a specified
dimension on the data. Often the leaf nodes are colored to show a
separate dimension of the data.

Which pixels did that drawmesh operation just draw to?

Ok, it's a relatively simple problem, I want to know where, in screen space, a particular mesh was just drawn. I plan on then storing that information in a data store of some kind so that when I interact with something in screen space, I can lookup in the register and find the object, i.e, click on the spaceship drawn on the screen and then select target etc.
I can't find any way of finding out which pixels the mesh was drawn to though...
Alternatively, if I'm missing something obvious regarding what it is that I Want to do, please let me know!
There is no easy way to do that. But you can use another texture as render target and render those meshes with unique colors.
So for example you give #FF0000 to your mesh A and draw it also to your second render target with that color. Now when you select a pixel from 2nd render target and look at that color, if it is #FF0000 you can understand that, the pixel is a part of mesh A. Thus you can easily pick the mesh drawn on a certain pixel when you click one of those pixels.
Why dont you Unproject your screen space coords into 3D space? The only complication I had was the fact that I'd be left with a plane, I could check if a Mesh intersected with that plane but I often had multiple candidates for 'picking'.
Check out Google for DirectX Unproject and there are various articles discussing it. It's sometimes complicated for some to implement but done well it's actually pretty nifty; don't get put off by the people online who say it doesn't work, it does work!