# Graphviz todo list 30-January-2009

The 4 categories give a rough time as to when a task should be done, and reflect an assessment of the task's ease multiplied by its importance. Thus, orthogonal layouts are extremely important but not easy, so they fall into category 2. The following denote owners:
AB=Arif Bilgin
ERG=Emden Gansner
JCE=John Ellson
SCN=Stephen North
YH=Yifan Hu

## Category 0

    ALL - Revise the buglist
    SCN - Update dot/neatoguide

## Category 1

    SCN - Lightweight edge labels in dot
    ? - Lightweight node labels in dot, just placed outside nodes.
    SCN - Treemaps
    JCE - Extend attribute set for line styles
    JCE - Allow arrowheads in the middle of edges
    JCE - Support single, uniform font descriptors à la pango
    ?   - Move generic node adjustment and spline routing out of neato
    ERG - New text labels with font elements <B>, <I>, <TT>, etc. (support via fontconfig or egregious hacks)
    AB  - Create Graph editor for Topview/Graphviz with OpenGL and GTK. (smyrna - in process) (Deprecate use of lefty)
    YH/ERG - Clusters in sfdp
    YH/ERG - Fixed nodes in sfdp

## Category 2

    SCN/AB - New dot core:
       - cgraph
       - new rank assignment (have prototype)
       - new mincross + clusters (partial prototype)
       - symmetrize layouts
      - Ulrik's improvements with network simplex
    JCE - Shapes
    	- SVG grammar or other grammar to specify node and arrow shapes
    	- user-defined nodes in all code generators
    YH/ERG - additional graph packing strategies
    ? - Filters for GraphML and Chaco formats.
    ? - Library for bundled edges (Given two sets of nodes, with positions,
    forming a bipartite graph, return splines to bundle the edges together)
    ? - better spacing of edges along the side of a node, especially
    exposed port sides. Perhaps extend compass points to S, N, E, W to
    mean anywhere along that side.
    ? - Tabular layout in rows and columns in dot (swim lanes)
    ? - Enable arbitrary depth clusters in neato using IPSEP
    ? - Allow mixed edge types within the same graph

## Category 3

    Generic label placement, with and without modifying graph layout.
    Support for compound graphs.
    Spline router improvement (Gordon's improvements, alpha adjustments, fewer
      inflection points)
    Fast incremental hierarchical layout
    Edge routing with just two vnodes per edge (after Kaufmann)
    Graph language improvements
      local name spaces
      subclassing
    Shapes - new parallelogram shape where angle is fixed for varying text
    Orthogonal layouts.
    Support rank=min/max within the context of a cluster

## General R&D directions

    Incremental layouts
    Dot with orthogonal, coalesced edges (e.g., this)
    Constraint-based layouts
    Display of large-graphs (hair ball problem)
     - relaxing constraining edges
     - edge bundles
    Venn diagrams
    Integration of geographic info - maps

## Done

    JCE - Extend attribute set for line thickness
    ERG - New text labels with font elements <FONT>
    ERG - Allow edges as line segments and polylines
    ERG - New multiedge code
    YH/ERG - New overlap adjustment strategies
    YH - Faster fdp (sfdp)
    ERG - Variable port depending on layout
    ERG - Better aspect ratio in dot
    ERG - New orthogonal routing code
    JCE - use floats not ints where appropriate
    YH - Filters for Matrix Market

## Retired

    JCE - Revise GV_FILE_PATH to work as directory list; remove loose ends
    ERG - eliminate the nonlinear adjustment
     - use convex hull or alpha shapes