getColorMap.ggobi {Rggobi}R Documentation

Set or query the colormap for a ggobi instance.

Description

These functions allow one to retrieve or set the contents of the color map used by a ggobi instance. The color map is an $n times 3$ matrix of of which each row contains the Red, Green and Blue values defining a color. Some colors have names and others are referenced simply by index in the colormap.

Usage

getColorMap.ggobi(.gobi=getDefaultGGobi())
setColorMap.ggobi(vals, .gobi=getDefaultGGobi(), scale = 65535)

Arguments

vals an $n$ by $3$ matrix giving the entries in the colormap in terms of their Red, Green and Blue components. The columns of the matrix should be in that order.
.gobi an identifier for the ggobi instance whose color map is to be set or retrieved. This is either an integer or an object of class ggobi.
scale a scaling factor by which the elements of the matrix are multiplied to convert them to internal format for use with Gtk.

Details

These functions convert the internal representation in ggobi of a colormap to an R matrix and vice-versa.

Value

getColorMap.ggobi returns a matrix of dimension $n times 3$ containing the Red, Green and Blue values with each element being between $0$ and $1$. The row names are those stored in the ggobi colormap, if supplied when reading the color map, or otherwise the index (starting at $1$).
setColorMap

Note

Currently, when operating on the colormap, one must operate on all of it, rather than operating on individual elements. In other words, one has to copy it all into R, modify the values and then transfer it back to ggobi. Since colormaps are reasonably small, can be specified in files and change infrequently, this is not a large penalty.

Author(s)

Duncan Temple Lang

References

http://www.ggobi.org/RSggobi.html

See Also

getColors.ggobi setColors.ggobi

Examples

  g <- ggobi(system.file("data", "flea.xml", package="Rggobi"), args="-noinit")
  g$getColorMap()
  names(g$getColorMap())
  
    # register a new color map with only 3 entries - Red, Green and Blue.
    # Then convert the colors' of the points to these values.
  cm <- diag(3)
  rownames(cm) <- c("R", "G","B")
  g$setColorMap(cm)

## Not run: 
  m["green", 1] <- .5
  g$setColorMap(m)
  g$setColors(rep("green", 20))
## End(Not run)

## Not run: 
  # Copy a colormap from one ggobi to another
 g1 <- ggobi(system.file("data", "flea.xml", package="Rggobi"), args="-noinit")
 g2 <- ggobi(system.file("data", "sat.xml", package="Rggobi"), args="-noinit")
 g2$setColorMap(g1$getColorMap())
## End(Not run)

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