Number: 2020
Title: Support configurable start position via rankdir for twopi
Submitter: Pander
Date: Mon Aug 23 07:39:48 2010
Subsys: Twopi
Version: 2.27.0 (20100810.0945)
System: *-*-
Severity: minor
Problem:
Please support start position for child nodes in twopi. As can be seen in attached example, the first child node is always placed North to North-East of the center node.

The rankdir could be used to this to rotate the positioning of all child nodes by 90, 180 and 270 degrees compared to the default situation as is existing already. The rankdir is by default TB (top to bottom) which suits the current positioning. BT (bottom to top) can be used for 180 degreed rotation of he placement and LR for 270 degrees and RL for 90 degrees.

The nodes are always placed in a clockwise order. There is no need to have an option for this, since defining the graph in reverse order results in reverse (counter clockwise) order.

All possibilities are documented in the attachment too.

Implementing this will provide the users with greater control over resulting graph generated by twopi leading to higher quality graphics and improved user satisfaction.
Input:

digraph "twopi rankdir" {
layout="twopi"
## all positioning is done clockwise, except in case of one child node

## default, first node is between North (preferred) and North-East
rankdir="TB"

## first node is between South (preferred) and South-West
#rankdir="BT"

## first node is between West (preferred) and North-West
#rankdir="LR"

## first node is between East (preferred) and South-East
#rankdir="RL"

00 -> {11 22 }
000 -> {111 222 333 }
0000 -> {1111 2222 3333 4444 }
00000 -> {11111 22222 33333 44444 55555 }
}
Owner: *
Status: Request