PlotTools
Description
"PlotTools" is an R package that allows the legends for continuous variables to be added to plots using the familiar functions of the default 'graphics' package. It also includes utility functions to manipulate irregular polygons and locate their centres.
Details
Full documentation is available online.
Author(s)
Maintainer: Martin R. Smith martin.smith@durham.ac.uk (ORCID) [copyright holder]
See Also
Useful links:
Report bugs at https://github.com/ms609/PlotTools/issues/
Colour to hexadecimal conversion
Description
Convert R colour to hexadecimal representation.
Usage
Col2Hex(col, alpha = FALSE)
Arguments
col
vector of any of the three kinds of R color specifications,
i.e., either a color name (as listed by colors()), a
hexadecimal string (see Details),
or a positive integer i meaning palette()[i].
alpha
logical value indicating whether the alpha channel (opacity) values should be returned.
Author(s)
Martin R. Smith (martin.smith@durham.ac.uk)
Examples
Col2Hex(1:3)
Col2Hex(c("peachpuff", "blue"), TRUE)
Polygon geometry
Description
Geometry functions for irregular polygons.
Usage
PolygonArea(x, y = NULL, positive = TRUE)
PolygonCentre(x, y = NULL)
PolygonCenter(x, y = NULL)
GrowPolygon(x, y = NULL, buffer = 0)
Arguments
x, y
Vectors containing the coordinates of the vertices of the polygon.
positive
If vertices are specified in an anticlockwise direction,
the polygon will be treated as a hole, with a negative area, unless
positive is set to TRUE.
Vertices specified in a clockwise sequence always yield a positive area.
buffer
Numeric specifying distance by which to grow polygon.
Value
PolygonArea() returns the area of the specified polygon.
PolygonCentre() returns a single-row matrix containing the
x and y coordinates of the geometric centre of the polygon.
GrowPolygon() returns coordinates of the vertices of polygon
after moving each vertex buffer away from the polygon's centre.
Functions
-
PolygonArea(): Calculate the area of an irregular polygon -
PolygonCentre(): Locate the centre of a polygon -
GrowPolygon(): Enlarge a polygon in all directions
Author(s)
Martin R. Smith (martin.smith@durham.ac.uk)
Examples
x <- c(-3, -1, 6, 3, -4)
y <- c(-2, 4, 1, 10, 9)
plot(x, y, frame.plot = FALSE)
polygon(x, y)
PolygonArea(x, y)
points(PolygonCentre(x, y), pch = 3, cex = 2)
polygon(GrowPolygon(x, y, 1), border = "darkgreen",
xpd = NA # Allow drawing beyond plot border
)
# Negative values shrink the polygon
polygon(GrowPolygon(x, y, -1), border = "red")
Produce a legend for continuous gradient scales
Description
Prints an annotated vertical bar coloured according to a continuous palette.
Usage
SpectrumLegend(
x = "topright",
...,
palette,
legend,
lty = 1,
lwd = 4,
bty = "o",
adj = if (horiz) c(0.5, 0.5) else c(0, 0.5),
horiz = FALSE,
lend = "butt",
cex = 1,
seg.len = 1
)
SizeLegend(
x = "topright",
...,
legend = character(0),
width = c(0, 1),
palette = par("col"),
scale = c("pch", "lwd"),
lty = 0,
lwd = 4,
bty = "o",
adj = if (horiz) c(0.5, 0.5) else c(0, 0.5),
horiz = FALSE,
lend = "butt",
cex = 1,
seg.len
)
Arguments
palette
Colour palette to depict.
Specify either a vector of colours, or a function such that palette(n)
returns a vector of n colours.
legend
Character vector with which to label points on palette.
Note that, in a vertical legend, values will be printed from top down;
use rev() to reverse the order.
lwd, lty, lend
Additional parameters to segments() ,
controlling line style. Use lend = "butt" (the default) if palette is
semitransparent, to avoid artefacts.
bty
Character specifying the type of box to be drawn around the
legend. The allowed values are "o" (the default) and "n".
cex
Character expansion factor relative to current par("cex").
width
Vector of length two specifying width of legend bar at base and top.
scale
Character string specifying whether width = 1 corresponds to:
"pch", the size of a plotting symbol with pch = 1;
"lwd", the width of a line with lwd = 1.
col
Colour used for the width bar.
Details
This convenience function is not yet very customizable; do file a GitHub issue if you would value additional functionality.
Note that the bg parameter to specify the background colour for the legend
box is not presently supported in vertical legends.
For use in vertical legends, open a GitHub issue.
Value
A list, returned invisibly, with components:
-
rectA list with components:-
w,h: positive numbers giving width and height of the legend's box. -
left,top: x and y coordinates of the upper left corner of the box.
-
-
text: A list with componentsx,y, numeric vectors of lengthlength(legend), giving the x and y coordinates of the legend's text(s).
Author(s)
Martin R. Smith (martin.smith@durham.ac.uk)
Examples
plot(0:1, 0:1, type = "n", frame.plot = FALSE,
xlab = "x", ylab = "y")
SpectrumLegend("bottomright", legend = c("Bright", "Middle", "Dark"),
palette = heat.colors(32L), lwd = 5,
inset = 0.05, # Inset from plot margin
title = "Brightness")
SpectrumLegend("topright", horiz = TRUE,
legend = seq(1, 9, by = 2), palette = 1:8)
SizeLegend(
"topleft", inset = 0.05, width = c(0, 2),
title = "Width",
legend = c("max", ".", ".", "min"),
palette = topo.colors, # Associate with a colour scale
y.intersp = 1.5 # Vertical space between labels (also moves title)
)
SizeLegend(
"bottomleft", horiz = TRUE, width = c(4, 1),
legend = c("Thick", "Thin"), palette = "darkred",
inset = 0.06 # Make space for the bar.
# A future release may calculate this automatically
)