Configuration of the renderers

The renderer options accept the following fields:

• layoutType: 'default' | 'Sugiyama LR' | 'Sugiyama TB' | 'Sugiyama BT' | 'Sugiyama RL' | 'IPSepCola' | 'MDS' This option defines the algorithm to layout the graph. When the 'default' option is used and all the edges in the graph are undirected, IPSepCola algorithm is used; otherwise, the graph is laid out with the Sugiyama Scheme.

  "Sugiyama TB": creates a layered top-to-bottom illustrated below.

IPSepCola An Incremental Procedure for Separation Constraint Layout of Graphs: illustrated below.

.

MDS: Pivot Multidemensional Scaling:

- `label`
  - `fontFamily: string` - CSS font-family value. Default `'sans-serif'`.
  - `fontSize: number` - Font size, default `16`.
  - `lineHeight: number` - Line height relative to the font size, default `1`.
  - `fontStyle: string` - CSS font-style value, default `'normal'`
  - `fontWeight: string | number` - CSS font-weight value, default `'normal'`.
- `edgeRoutingMode: EdgeRoutingMode` - Enum for supported routing modes, including `Spline`, `SplineBundling` `StraightLine`, `SugiyamaSplines`, `Rectilinear`, `RectilinearToCenter`, `None`. Default varies by `layoutType`.

## Layout Editing

There are some layout editing capabilities that are demonstrated by the video below:


[![video](./docs/video.png)](https://youtu.be/j-zsysohSU0)
They include:

- dragging of the entities; one can select and drag a group of entities as well
- deletion of the entities
- node insertion
- edge insertion
- editing the node label
- edge curve editing
- undo/redo

  The current limitations are:

- the edge routing switches to straight lines when dragging
- undo/redo does not work for node label text editing
- the node does not resize for the new label text
- only [the viewer with SVG](https://microsoft.github.io/msagljs/svg_backend/index.html) supports editing.