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Last data update: 2014.03.03

R: Draw a curve representing a function

grid.function

R Documentation

Draw a curve representing a function

Description

Draw a curve representing a function.

Usage

grid.function(...)
functionGrob(f, n = 101, range = "x", units = "native",
             name = NULL, gp=gpar(), vp = NULL)

grid.abline(intercept, slope, ...)

Arguments

`f`	A function that must take a single argument and return a list with two numeric components named `x` and `y`.
`n`	The number values that will be generated as input to the function `f`.
`range`	Either `"x"`, `"y"`, or a numeric vector. See the ‘Details’ section.
`units`	A string indicating the units to use for the `x` and `y` values generated by the function.
`intercept`	Numeric.
`slope`	Numeric.
`...`	Arguments passed to `grid.function()`
`name`	A character identifier.
`gp`	An object of class `gpar`, typically the output from a call to the function `gpar`. This is basically a list of graphical parameter settings.
`vp`	A Grid viewport object (or NULL).

Details

n values are generated and passed to the function f and a series of lines are drawn through the resulting x and y values.

The generation of the n values depends on the value of range. In the default case, dim is "x", which means that a set of x values are generated covering the range of the current viewport scale in the x-dimension. If dim is "y" then values are generated from the current y-scale instead. If range is a numeric vector, then values are generated from that range.

grid.abline() provides a simple front-end for a straight line parameterized by intercept and slope.

Value

A functiongrob grob.

Author(s)

Paul Murrell

Examples

    # abline
    # NOTE: in ROOT viewport on screen, (0, 0) at top-left
    #       and "native" is pixels!
    grid.function(function(x) list(x=x, y=0 + 1*x))
    # a more "normal" viewport with default normalized "native" coords
    grid.newpage()
    pushViewport(viewport())
    grid.function(function(x) list(x=x, y=0 + 1*x))
    # slightly simpler
    grid.newpage()
    pushViewport(viewport())
    grid.abline()
    # sine curve
    grid.newpage()
    pushViewport(viewport(xscale=c(0, 2*pi), yscale=c(-1, 1)))
    grid.function(function(x) list(x=x, y=sin(x)))
    # constrained sine curve
    grid.newpage()
    pushViewport(viewport(xscale=c(0, 2*pi), yscale=c(-1, 1)))
    grid.function(function(x) list(x=x, y=sin(x)),
                  range=0:1)
    # inverse sine curve
    grid.newpage()
    pushViewport(viewport(xscale=c(-1, 1), yscale=c(0, 2*pi)))
    grid.function(function(y) list(x=sin(y), y=y),
                  range="y")
    # parametric function
    grid.newpage()
    pushViewport(viewport(xscale=c(-1, 1), yscale=c(-1, 1)))
    grid.function(function(t) list(x=cos(t), y=sin(t)),
                  range=c(0, 9*pi/5))
    # physical abline
    grid.newpage()
    grid.function(function(x) list(x=x, y=0 + 1*x),
                  units="in")

Results


R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

R is free software and comes with ABSOLUTELY NO WARRANTY.
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Type 'license()' or 'licence()' for distribution details.

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Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> library(grid)
> png(filename="/home/ddbj/snapshot/RGM3/R_rel/result/grid/grid.function.Rd_%03d_medium.png", width=480, height=480)
> ### Name: grid.function
> ### Title: Draw a curve representing a function
> ### Aliases: grid.function functionGrob grid.abline
> ### Keywords: dplot
> 
> ### ** Examples
> 
>     # abline
>     # NOTE: in ROOT viewport on screen, (0, 0) at top-left
>     #       and "native" is pixels!
>     grid.function(function(x) list(x=x, y=0 + 1*x))
>     # a more "normal" viewport with default normalized "native" coords
>     grid.newpage()
>     pushViewport(viewport())
>     grid.function(function(x) list(x=x, y=0 + 1*x))
>     # slightly simpler
>     grid.newpage()
>     pushViewport(viewport())
>     grid.abline()
>     # sine curve
>     grid.newpage()
>     pushViewport(viewport(xscale=c(0, 2*pi), yscale=c(-1, 1)))
>     grid.function(function(x) list(x=x, y=sin(x)))
>     # constrained sine curve
>     grid.newpage()
>     pushViewport(viewport(xscale=c(0, 2*pi), yscale=c(-1, 1)))
>     grid.function(function(x) list(x=x, y=sin(x)),
+                   range=0:1)
>     # inverse sine curve
>     grid.newpage()
>     pushViewport(viewport(xscale=c(-1, 1), yscale=c(0, 2*pi)))
>     grid.function(function(y) list(x=sin(y), y=y),
+                   range="y")
>     # parametric function
>     grid.newpage()
>     pushViewport(viewport(xscale=c(-1, 1), yscale=c(-1, 1)))
>     grid.function(function(t) list(x=cos(t), y=sin(t)),
+                   range=c(0, 9*pi/5))
>     # physical abline
>     grid.newpage()
>     grid.function(function(x) list(x=x, y=0 + 1*x),
+                   units="in")
> 
> 
> 
> 
> 
> dev.off()
null device 
          1 
>