rviewgraph (version 1.4.2)

rViewGraph: This is a function to create and start a 'Java' graph animation GUI.

Description

Creates and starts an animated graphical user interface (GUI) for positioning the vertices of a graph in 2 dimensions.

Usage

rViewGraph(object, names, cols, shapes, layout, directed, running, ...)
# S3 method for default
rViewGraph(
  object,
  names = NULL,
  cols = "yellow",
  shapes = 0,
  layout = NULL,
  directed = FALSE,
  running = TRUE,
  ...
)
# S3 method for igraph
rViewGraph(
  object,
  names = igraph::V(object)$name,
  cols = "yellow",
  shapes = 0,
  layout = igraph::layout.random(object),
  directed = igraph::is.directed(object),
  running = TRUE,
  ...
)

Value

rViewGraph is intended only for interactive use. When used in a non-interactive environment it immediately exits returning the value NULL. Otherwise, all versions of rViewGraph return a list of functions that control the actions of the interactive viewer.

run()

Starts the GUI running if it's not already doing so.

stop()

Stops the GUI running if it's running.

hide()

Stops the GUI and hides it.

show()

Shows the GUI. If it was running when hide was called, it starts running again.

getLayout()

Returns the coordinates of the vertices as currently shown in the GUI. These are given as an n by 2 array as required for the layout parameter of rViewGraph itself.

setLayout(layout = NULL)

Sets the coordinates of the vertices to the given values. layout is specified in the same way as required for the layout parameter of rViewGraph itself. The default has layout set to NULL, and new random coordinates are generated.

hidePaper()

By default the GUI indicates, with a different colour, the portion of the plane that corresponds to the current choice of paper for printing. This function removes that area.

showPaper(size = "letter", landscape = TRUE)

Indicates, with a different colour, the portion of the plane corresponding to a choice of paper for printing. size can be any of letter, A4, A3, A2, A1, A0, C1, or C0. landscape can be either TRUE or FALSE, in which case portrait orientation is used. The default is to show the portion of the plane that would be printed on US letter in landscape orientation.

hideAxes()

By default, axes are shown to indicate the origin. This function hides them.

showAxes()

Shows the axes if they are hidden.

writePostScript()

This starts a Java PostScript print job dialog box that can be used send the current view of the graph to a printer or to write a PostScript file. The plot produced should closely match what is indicated by showPaper.

ps()

Alias for writePostScript.

Arguments

object

the object specifying the graph. This can be specified in various ways:

• A square n = dim(object)[1] by n real valued incidence matrix. This will create a graph with n vertices indexed by 1:n and edges between vertices with indices i and j if object[i,j] != 0. If the graph is directed edges are directed from i to j if the entry is positive, and from j to i if the entry is negative.

• An m = dim(object)[1] by 2 matrix of positive integers specifying the indexes of the vertices at the ends of m edges. This will create a graph with n = max(object) vertices indexed by 1:max(object) and edges connecting the vertex indexed by object[i,1] to the vertex indexed by object[i,2] for each i in 1:m. If the graph is directed, the edges are directed from object[i,1] to object[i,2]. NOTE: A 2 by 2 matrix will be interpreted as an incidence matrix, not an array of edges.

• A vector of 2*m positive integers specifying the indexes of the vertices at the ends of m = length(object)/2 edges. This is the way in which igraph specifies edges. If x is such a vector, calling rViewGraph{x} is equivalent to calling rViewGraph(matrix(x,ncol=2,byrow=F)).

• An igraph graph object.

names

the names of the vertices. This is an object that can be interpreted as a vector of strings that will be used to label the vertices. If the length is less than the number of vertices, the names will be cycled. The default is names = 1:n, where n is the number of vertices. If unlabeled vertices are required use, for example, names=" ". The size of the string is used to determine the size of the vertex so, for instance, names = " A " will produce bigger vertices than names = "A".

cols

the colours of the vertices. This is on object that can be interpreted as a vector of colours specified in the usual R ways. If the length is less than the number of vertices, the colours will be cycled. The default is cols = "yellow".

shapes

the shapes of the vertices. This is a vector of integers specifying the shapes of the vertices. The available shapes are:

• 0 = rectangle

• 1 = oval

• 2 = diamond

• any other values are taken as 0.

The default is shapes = 0.

layout

the starting positions of the vertices. This is an n by 2 array of reals with layout[i,] specifying the horizontal and vertical coordinates for the starting point of the ith vertex. By default this is set to NULL in which case random starting points are used.

directed

indicates whether or not the graph is directed.

running

indicates whether or not to start with the animation running.

...

passed along extra arguments.

Interactive mouse, key and slide bar controls

• Slide bars at the bottom of the GUI control the repulsive force in the energy equation used to set the coordinates. If the graph is undirected, there is a single 'Repulsion' parameter, if directed, there are 'X-Repulsion' and 'Y-Repulsion' parameters, and a 'Gravity' parameter that influences how these are combined.

• Mouse operations without shift key and without control key pressed.

  1. Left mouse: Drags a vertex. Vertex is free on release.

  2. Middle mouse: Drags a vertex. Vertex is fixed at release position.

  3. Right mouse: Translates the view by the amount dragged. A bit like putting your finger on a piece of paper and moving it.

  4. Double click with any mouse button in the background: Resets the vertices to new random positions.

• Mouse operations with shift key but without control key pressed.

  1. Left mouse: Drags a vertex and the component it is in. Vertex and component free on release.

  2. Middle mouse: Drags a vertex and the component it is in. Vertex and component are fixed at release positions.

  3. Right mouse: Translates the positions of the vertices relative to the position of the canvas by the amount dragged. This is useful to center the picture on the canvas ready for outputting.

• Mouse operations without shift key but with control key pressed.

  1. Left mouse: Click on a vertex to un-hide any hidden neighbours.

  2. Middle mouse: Click on a vertex to hide it.

  3. Double click left mouse: Un-hides all hidden vertices.

  4. Double click middle mouse: Hides all vertices.

• Mouse operations with shift key and with control key pressed.

  1. Left mouse: Click on a vertex to un-hide all vertices in the same component.

  2. Middle mouse: Click on a vertex to hide it and the component it is in.

• Key functions without shift key pressed. Mouse has to be in the picture canvas.

  1. Up arrow: Increases the scale of viewing by 10%.

  2. Down arrow: Decreases the scale of viewing by 10%.

  3. Left arrow: Rotates the view by 15 degrees clockwise.

  4. Right arrow: Rotates the view by 15 degrees anticlockwise.

  5. Home key: Undoes all scalings and rotations and places the origin at the top left corner of the canvas.

• Key functions with shift key pressed. Mouse has to be in the picture canvas.

  1. Up arrow: Increases the vertex positions by 10% relative to the scale of the canvas.

  2. Down arrow: Decreases the vertex positions by 10% relative to the scale of the canvas.

  3. Left arrow: Rotates the vertex positions by 15 degrees clockwise relative to the canvas orientation.

  4. Right arrow: Rotates the vertex positions by 15 degrees anticlockwise relative to the canvas orientation.

Author

Alun Thomas

Details

Creates and starts a 'Java' GUI showing a real time animation of a Newton-Raphson optimization of a force function specified between the vertices of an arbitrary graph. There are attractive forces between adjacent vertices and repulsive forces between all vertices. The repulsions go smoothly to zero in a finite distance between vertices so that, unlike some other methods, different components don't send each other off to infinity.

The program is controlled by a slide bar, some buttons, the arrow, home and shift keys, but mostly by mouse operations. All three mouse buttons are used. The interactive mouse, key and slide bar operations are described below.

Examples

require(rviewgraph)

# First generate the random edges of an Erdos Renyi random graph.
f = sample(100,size=200,replace=TRUE)
t = sample(100,size=200,replace=TRUE)

# The following should all show the same graph:
# ... specified as a two column matrix.
v1 = rViewGraph(cbind(f,t))

# ... in 'igraph' preferred format.
v2 = rViewGraph(c(f,t))

# ... as an adjacency matrix.
x = matrix(0,ncol=max(f,t),nrow=max(f,t))
for (i in 1:length(f)) x[f[i],t[i]] = 1
v3 = rViewGraph(x)


# Specifying names, colours and shapes.

# Use unlabeled vertices, as red, green and blue diamonds.
v4 = rViewGraph(cbind(f,t), names = "  ", cols = c(2,3,4), shapes=2)

# Use yellow vertices with random shapes, labeled with capital letters.
y = matrix(sample(1:26,100,TRUE),ncol=2)
v5 = rViewGraph(y,names=LETTERS,cols="cyan",shapes=sample(0:2,26,TRUE))


# Controlling a currently active GUI.
if (!is.null(v5))
{
	# Shift the coordinates, although this is more 
# easily done with mouse controls.
	v5$setLayout(100 + v5$getLayout())

# Reset the coordinates to random values.
v5$setLayout()

	# Pepare a plot for printing, fix it, and start a PostScript print job.
	v5$hideAxes()
	v5$showPaper("A3",F)
	v5$stop()
	v5$writePostScript()
}