Display color raster with plet()

[aloboa]

Given

s <- rast(system.file("ex/logo.tif", package="terra"))   
s
plot(s)

Is it possible to get plet() to display the same colors?

plet(s)

Same result with

ss <- colorize(s, "col")
plet(ss)

[aloboa]

With terra 1.7.83 I get now:

s <- rast(system.file("ex/logo.tif", package="terra"))  
plet(s)

which is better but still not the same as
plot(s)

[rhijmans]

Thanks. This now works as expected.

[aloboa]

Yes!
But:

s <- rast(system.file("ex/logo.tif", package="terra"))/100
plotRGB(s,1,2,3)
plotRGB(s,1,2,3,stretch="lin")
plet(s)

The stretch="lin" option for plet() would be most useful.

[rhijmans]

You can now do

library(terra)
s <- rast(system.file("ex/logo.tif", package="terra"))
plet(s, stretch="hist")

[aloboa]

Not with last version 1.8.3:

> library(terra)
terra 1.8.3
s <- rast(system.file("ex/logo.tif", package="terra"))/100
plotRGB(s,1,2,3)
plotRGB(s,1,2,3,stretch="lin")

plet(s)

Same with:

plet(s, stretch="hist")
plet(s, stretch="lin")

[rhijmans]

By my example works (at least for me). You divide the raster by 100 and then it is no longer an RGB image.

[aloboa]

You divide the raster by 100 and then it is no longer an RGB image.

stretch="lin" is not supposed to take care of that, as it does in plotRGB()?

[rhijmans]

With plotRGB there is no doubt that we are dealing with an RGB raster. With plot and plet that needs to be explicit.

[rhijmans]

For example compare the two plots

library(terra)
s <- rast(system.file("ex/logo.tif", package="terra"))
plot(s)
plot(s/100)

[aloboa]

I see, but

> class(s)
[1] "SpatRaster"
attr(,"package")
[1] "terra"
> class(s/100)
[1] "SpatRaster"
attr(,"package")
[1] "terra"

still think that stretch="lin" should transform the object to the (0,255) range, and thus I would expect
plot(r/100, stretch="lin)
to be the same colors as
plot(r, stretch="lin")

But you must have your reasons.
What I would like to know is, how should we display r/100 to have the same colors as plot(r) ?
Just plotRGB(r/100, stretch="lin) ?

What about plet()? there is no pleRGB()

[rhijmans]

A SpatRaster looses its RGB channels if you do an arithmetic operation

library(terra)
s <- rast(system.file("ex/logo.tif", package="terra"))
RGB(s)
RGB(s/100)

You can set the channels when needed

r <- s/100
RGB(r) <- 1:3
# or set.RGB(r, 1:3)
plot(r, stretch="lin")

To make that more compact, you can now also do

r <- s/100
plot(RGB(r, 1:3), stretch="lin")

There is no pletRGB because my thinking is that you can accomplish the same with the above at the expense of a pair of parentheses. In stead of pletRGB() you now have plet(RGB())

[aloboa]

Excellent!