# Graphviz todo list 25-May-2012

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
DFWC=Don Caldwell
DP=Dwight Perry
ERG=Emden Gansner
JCE=John Ellson
SCN=Stephen North
YH=Yifan Hu

## Category 0

    ALL - Revise the buglist; fix bugs
    SCN - Update dot/neatoguide

## Category 1

    JCE - Extend attribute set for line styles
    JCE - Allow arrowheads in the middle of edges
    JCE - Support single, uniform font descriptors à ala pango
    ?   - Move generic node adjustment and spline routing out of neato
    AB  - smyrna
    	1 QT
    	2 Widget library. Plugins. Printing.
    	3 Full dotty replacement incl. history, checkpoints, scripting, undo.
    	4 General editor
    YH/ERG - Clusters in sfdp
    YH/ERG - Fixed nodes in sfdp
    ERG - Finish orthogonal edges (edge labels in dot; ports)
    ERG - Add stack frames/local variables to gvpr
    ERG - GvMap integrated tool
    ? - Finish handling of loops using arbitrary ports

## Category 2

    SCN/AB - New dot core:
       - 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 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.
    ERG - Tabular layout in rows and columns in dot (swim lanes)
          Crossing minimization with some nodes in columns
    ? - Enable arbitrary depth clusters in neato using IPSEP
    ? - Allow mixed edge types within the same graph
    ? - Off-load more to pango, such as linebreaks, right-to-left characters, etc.
    ? - Allow text at an angle

## Category 3

    Generic label placement modifying graph layout.
    Support for compound graphs.
    Allow varied layouts within clusters - recursion
    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
    True orthogonal layouts.
    Support rank=min/max within the context of a cluster

## General R&D problems

    Dot with aspect ratio allowing clusters
    Dot with aspect ratio < 1
    Incremental layouts
    Dot with orthogonal, coalesced edges (e.g., this)
    Generalizing the above, support for hyperedges
    Constraint-based layouts
    Display of large-graphs (hair ball problem)
     - relaxing constraining edges
     - edge bundles
     - other
    Venn diagrams
    Integration of geographic info - maps
    Aspect ratio in dot with clusters
    Dot with fixed width
    Adjust graph to allow no edge-node overlap with line segment edges

## Done

    SCN/ERG - Move dot to cgraph
    SCN/ERG - new rank assignment
    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
    ERG - New text labels with font elements <B>, <I>, <TT>, etc. (support via fontconfig or egregious hacks)
    AB  - smyrna
    	1 Design incl. 3D navigation, multiple graphs and viewports. Avoid modes.
    	2 Stable GUI. 3D mouse.
    DFWC - Lightweight edge labels in dot
    DFWC - Lightweight node labels in dot, just placed outside nodes.
    DFWC - Generic label placement without modifying graph layout.
    YH/ERG - Treemaps
    DP/ERG   - Clusters/HTML tables with rounded edges
    ERG - Filters for GraphML

## 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