rasterImage
Draw One or More Raster Images
rasterImage draws a raster image at the given locations and sizes.
- Keywords
- aplot
Usage
rasterImage(image,
xleft, ybottom, xright, ytop,
angle = 0, interpolate = TRUE, …)Arguments
- image
a
rasterobject, or an object that can be coerced to one byas.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.
- …
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.
See Also
rect,
polygon, and segments and others
for flexible ways to draw shapes.
dev.capabilities to see if it is supported.
Examples
library(graphics)
# NOT RUN {
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)
# }