rasters {baffle}

Plot raster image

Description

Plot raster image centered at 'x' and 'y' coordinates scaled to diameter 'd'.

Usage

rasters(x, y, image, d = 0.9, dx = NA, dy = NA, rotate = 0, ...)

Arguments

x, y

coordinates

image

raster image

d

**optional** diameter, see details

dx, dy

**optional** diameter in either coordinate direction

rotate

**optional** clockwise rotation in degrees (0-360°)

...

**optional** other parameters passed to [graphics::rasterImage()], such as 'interpolate'

Details

The 'rasters()' function is a convenient wrapper around [graphics::rasterImage()] with similar interface to the [Shapes] functions available in this package (such as [square()], [circle()] and [rcpoly()]).

The raster image is plotted centered at the 'x' and 'y' coordinates and scaled to the diameter size 'd'. When 'dx' and 'dy' are 'NA', the proportions of the raster are kept unchanged, otherwise they are scaled to the specified size in either direction. This scaling is done before rotation.

Unlike in 'rasterImage', the rotation is performed clockwise and the rotation axis is the center of the raster (i.e., the provided x and y coordinates), rather than the bottom left coordinate 'x0'. This rotation is performed after scaling.

As of yet, the rotation is accurate only when the aspect ratio is set to 1 ('asp=1') through the 'graphics::plot.window()' call.

The 'rasters()' function is fully vectorized.

Value

No return value, called for side effects

See Also

[grDevices::as.raster()] and [graphics::rasterImage()]

Examples

# create plotting window
plot.new(); plot.window(c(-1,1), c(-1,1), asp=1); axis(1); axis(2)

# create raster image, alpha is convenient when overplotting
img = matrix(adjustcolor("black", alpha.f=0.3), 3, 3)
img[2, 2] = adjustcolor("white", alpha.f=0.3)
img = as.raster(img)

rasters(0, 0, img)

# interpolate=FALSE makes quite a difference
rasters(0, 0, img, interpolate=FALSE)

# arguments are vectorized, standard recycling rules apply
rasters(0, 0, img, interpolate=FALSE, rotate=c(30, 60, 90))
rasters(c(-1, -0.5,  0.5, 1), c(1, 0.5, -0.5, -1), img, interpolate=FALSE)