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rasterImage: Draw One or More Raster Images

rasterImage

R Documentation

Draw One or More Raster Images

Description

rasterImage draws a raster image at the given locations and sizes.

Usage

rasterImage(image,
            xleft, ybottom, xright, ytop,
            angle = 0, interpolate = TRUE, ...)

Arguments

`image`	a `raster` object, or an object that can be coerced to one by `as.raster`.
`xleft`	a vector (or scalar) of left x positions.
`ybottom`	a vector (or scalar) of bottom y positions.
`xright`	a vector (or scalar) of right x positions.
`ytop`	a vector (or scalar) of top y positions.
`angle`	angle of rotation (in degrees, anti-clockwise from positive x-axis, about the bottom-left corner).
`interpolate`	a logical vector (or scalar) indicating whether to apply linear interpolation to the image when drawing.
`...`	graphical parameters.

Details

The positions supplied, i.e., xleft, ..., are relative to the current plotting region. If the x-axis goes from 100 to 200 then xleft should be larger than 100 and xright should be less than 200. The position vectors will be recycled to the length of the longest.

Plotting raster images is not supported on all devices and may have limitations where supported, for example (e.g., for postscript and X11(type = "Xlib") is restricted to opaque colors). Problems with the rendering of raster images have been reported by users of windows() devices under Remote Desktop, at least under its default settings.

You should not expect a raster image to be re-sized when an on-screen device is re-sized: whether it is is device-dependent.

Examples

require(grDevices)
## set up the plot region:
op <- par(bg = "thistle")
plot(c(100, 250), c(300, 450), type = "n", xlab = "", ylab = "")
image <- as.raster(matrix(0:1, ncol = 5, nrow = 3))
rasterImage(image, 100, 300, 150, 350, interpolate = FALSE)
rasterImage(image, 100, 400, 150, 450)
rasterImage(image, 200, 300, 200 + xinch(.5), 300 + yinch(.3),
            interpolate = FALSE)
rasterImage(image, 200, 400, 250, 450, angle = 15, interpolate = FALSE)
par(op)