grid.raster
Render a raster object
Description
Render a raster object (bitmap image) at the given location, size, and orientation.
Usage
grid.raster(image, x = unit(0.5, "npc"), y = unit(0.5, "npc"), width = NULL, height = NULL, just = "centre", hjust = NULL, vjust = NULL, interpolate = TRUE, default.units = "npc", name = NULL, gp = gpar(), vp = NULL) rasterGrob(image, x = unit(0.5, "npc"), y = unit(0.5, "npc"), width = NULL, height = NULL, just = "centre", hjust = NULL, vjust = NULL, interpolate = TRUE, default.units = "npc", name = NULL, gp = gpar(), vp = NULL)
Arguments
image | Any R object that can be coerced to a raster object. |
x | A numeric vector or unit object specifying x-location. |
y | A numeric vector or unit object specifying y-location. |
width | A numeric vector or unit object specifying width. |
height | A numeric vector or unit object specifying height. |
just | The justification of the rectangle relative to its (x, y) location. If there are two values, the first value specifies horizontal justification and the second value specifies vertical justification. Possible string values are: |
hjust | A numeric vector specifying horizontal justification. If specified, overrides the |
vjust | A numeric vector specifying vertical justification. If specified, overrides the |
default.units | A string indicating the default units to use if |
name | A character identifier. |
gp | An object of class |
vp | A Grid viewport object (or NULL). |
interpolate | A logical value indicating whether to linearly interpolate the image (the alternative is to use nearest-neighbour interpolation, which gives a more blocky result). |
Details
Neither width
nor height
needs to be specified, in which case, the aspect ratio of the image is preserved. If both width
and height
are specified, it is likely that the image will be distorted.
Not all graphics devices are capable of rendering raster images and some may not be able to produce rotated images (i.e., if a raster object is rendered within a rotated viewport). See also the comments under rasterImage
.
All graphical parameter settings in gp
will be ignored, including alpha
.
Value
A rastergrob grob.
Author(s)
Paul Murrell
See Also
dev.capabilities
to see if it is supported.
Examples
redGradient <- matrix(hcl(0, 80, seq(50, 80, 10)), nrow=4, ncol=5) # interpolated grid.newpage() grid.raster(redGradient) # blocky grid.newpage() grid.raster(redGradient, interpolate=FALSE) # blocky and stretched grid.newpage() grid.raster(redGradient, interpolate=FALSE, height=unit(1, "npc")) # The same raster drawn several times grid.newpage() grid.raster(0, x=1:3/4, y=1:3/4, width=.1, interpolate=FALSE)
Copyright (©) 1999–2012 R Foundation for Statistical Computing.
Licensed under the GNU General Public License.