ursa (version 3.10.4)

panel_raster: Add raster to the image panel

Description

If specified image has 3 or 4 bands, then color composite is plotted on image panel, else the image is plotted regarding to its color table.

Usage

panel_raster(...)

Value

If argument obj has strictly one band, then function returns color table - object of class ursaColorTable, which can be used as an input argument for the colorbar legend (function legend_colorbar). Otherwise function returns NULL value.

Arguments

...

Set of arguments, which are recognized via their names (using regular expressions) and classes.
1. Passed to colorize.
2. interpreted in this function:

"(^$|obj)" as obj

Object of class ursaRaster. Raster band for plotting. Multiple bands are allowed if then can be interpreted as RGB or RGBA.

"useRaster" as useRaster

Logical. If TRUE then a bitmap raster is used to plot the image instead of polygons. See argument useRaster in function image. Default depends on PNG device (getOption("ursaPngDevice"), which is set up in compose_open); it is TRUE for "cairo" device, and FALSE for "windows" device.

"interp(olate)*" as interpolate

Logical. Passed as argument interpolate to function rasterImage.

"(alpha|transp(aren(cy)*)*)" as alpha

Numeric or character. Level of transparency. If numeric, the either 0 <= alpha <= 1 or 0 <= alpha <= 255. If character, then one byte of hexadecimal value "00" <= alpha <= "FF". If NA, then transparency is used from colortable, else transparency of colortable is overwritten by alpha. Default is NA.

"verb(ose)*" as verbose

Logical. Value TRUE may provide some additional information on console. Default is FALSE.

Author

Nikita Platonov

Details

If obj is list of raster images, then panel_raster is applied to each item of list, and colortable of last item is returned.

If obj has 3 or 4 bands then obj is interpreted as RGB(A) image.

Function attempts to speed up plotting by reduce image matrix for big rasters.

Examples

session_grid(NULL)
# example no.1 -- direct use
session_grid(regrid(mul=1/32))
dima <- with(session_grid(),c(columns,rows,3))
a <- ursa_new(value=array(runif(prod(dima),min=127,max=255),dim=dima))
p <- colorize(a,pal=c("black","white"),ramp=TRUE,value=0:256)
compose_open(layout=c(2,3),skip=4,legend=list(list("top","full"),list("bottom",2:3)))
for (i in seq(6)) {
   panel_new()
   if (i<4)
      panel_raster(p[i])
   else
      panel_raster(a,interpolate=i==5)
   panel_decor(col="black",coast=FALSE)
   panel_annotation(c("red","green","blue"
                    ,"interpolate=FALSE","interpolate=TRUE"))
}
legend_colorbar(p,label=seq(0,256,by=16),units="channels")
legend_mtext("color composite")
compose_close()

# example no.2 -- indirect use
ps <- pixelsize(NULL)
display(ps,raster.verb=TRUE)

# example no.3 -- color table for legend
session_grid(NULL)
compose_open()
panel_new()
ct <- panel_raster(ps,pal=terrain.colors)
panel_decor()
compose_legend(ct)
compose_close()