Re: [R] Palettes {grDevices} - wrong number of colors returned?
Just for the record: Duncan and Martin (Maechler) improved my proposed patch and Martin committed it to R-devel now. Thank you, Sigbert, for reporting the issue! On Thu, 23 Feb 2023, Achim Zeileis wrote: On Thu, 23 Feb 2023, Duncan Murdoch wrote: On 23/02/2023 6:09 a.m., Achim Zeileis wrote: Duncan, thanks for your feedback. I just received your response after sending out mine. You came to the same conclusion. Should I prepare a patch and send it to you so that you can also have a look? Or view Bugzilla? Copying Sigbert's message to Bugzilla is a good idea so it can be referred to from the NEWS entry. Good point. I've written a new description, though, because the are even more problems with the alpha vector handling than suggested by Sigbert. The bug report is now at: https://bugs.R-project.org/show_bug.cgi?id=18476 If you want to submit a patch along with it, let me know and I'll take a look at it. There is both a patch and a test script in the attachments of the bug report. Let me know if something needs further fixing. Best wishes, Achim __ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Palettes {grDevices} - wrong number of colors returned?
On Thu, 23 Feb 2023, Duncan Murdoch wrote: On 23/02/2023 6:09 a.m., Achim Zeileis wrote: Duncan, thanks for your feedback. I just received your response after sending out mine. You came to the same conclusion. Should I prepare a patch and send it to you so that you can also have a look? Or view Bugzilla? Copying Sigbert's message to Bugzilla is a good idea so it can be referred to from the NEWS entry. Good point. I've written a new description, though, because the are even more problems with the alpha vector handling than suggested by Sigbert. The bug report is now at: https://bugs.R-project.org/show_bug.cgi?id=18476 If you want to submit a patch along with it, let me know and I'll take a look at it. There is both a patch and a test script in the attachments of the bug report. Let me know if something needs further fixing. Best wishes, Achim __ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Palettes {grDevices} - wrong number of colors returned?
On 23/02/2023 6:09 a.m., Achim Zeileis wrote: Duncan, thanks for your feedback. I just received your response after sending out mine. You came to the same conclusion. Should I prepare a patch and send it to you so that you can also have a look? Or view Bugzilla? Copying Sigbert's message to Bugzilla is a good idea so it can be referred to from the NEWS entry. If you want to submit a patch along with it, let me know and I'll take a look at it. Duncan __ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Palettes {grDevices} - wrong number of colors returned?
Thanks, Sigbert, good catch. The reason that this happens is the following: rainbow(), heat.colors(), terrain.colors(), cm.colors(), and topo.colors() are all just front-ends to calls to hsv() for Hue-Saturation-Value colors. (BTW: This is also the main reason why they yield palettes with rather poor perceptual properties.) All of the palette functions just pass on the alpha argument to all hsv(..., alpha=alpha) calls. And in each case if the length of alpha and the number of colors does not match the shorter element is recycled to the length of the longer one. Thus, if n == length(alpha), as in your example, then those functions that can generate all colors with a single call of hsv() do the right thing (rainbow and heat.colors). Those, that need two hsv() calls yield 2 * n colors (cm.colors and terrain.colors). And in topo.colors() where three hsv() calls are used we get 3 * n colors. My suggested solution would be to do something like alpha <- rep_len(alpha, n) early on in the palette functions and then assure that the correct elements of alpha are passed to hsv(). The same should be done in those functions that work correctly for n = length(alpha) because it will assure that we always get n colors and not more. For example, the case with n < length(alpha) is also unexpected: hcl.colors(2, alpha = c(0, 0.25, 0.5, 0.75, 1)) ## [1] "#4B005500" "#FDE33340" "#4B005580" "#FDE333BF" "#4B0055FF" Or even worse: gray.colors(2, alpha = c(0, 0.25, 0.5, 0.75, 1)) ## Error in gray(seq.int(from = start^gamma, to = end^gamma, length.out = n)^(1/gamma), : ## attempt to set index 2/2 in SET_STRING_ELT If someone from R Core thinks that my proposed strategy is a good way forward, I'm happy to work on a patch. Sigbert, if you are looking for a solution: (1) Don't use heat.colors, terrain.colors, topo.colors, cm.colors, they are all quite terribel ;-) (2) If you really want to use them, put on the alpha afterwards, e.g., using colorspace::adjust_transparency: colorspace::adjust_transparency(topo.colors(3), alpha = c(0, 0.5, 1)) ## [1] "#4C00FF00" "#00FF4D80" "#00FF" hth, Achim On Thu, 23 Feb 2023, Sigbert Klinke wrote: Hi, I would have expected that I get always 3 colors as result which is not true: hcl.colors(3, alpha=c(0, 0.5, 1)) # 3 colors rainbow(3, alpha=c(0, 0.5, 1))# 3 colors heat.colors(3, alpha=c(0, 0.5, 1))# 3 colors terrain.colors(3, alpha=c(0, 0.5, 1)) # 6 colors cm.colors(3, alpha=c(0, 0.5, 1)) # 6 colors topo.colors(3, alpha=c(0, 0.5, 1))# 9 colors R-Version and platform: R version 4.2.2 Patched (2022-11-10 r83330) -- "Innocent and Trusting" Copyright (C) 2022 The R Foundation for Statistical Computing Platform: x86_64-pc-linux-gnu (64-bit) Bug or feature? Sigbert -- https://hu.berlin/sk https://www.stat.de/faqs https://hu.berlin/mmstat https://hu.berlin/mmstat-ar __ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. __ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Palettes {grDevices} - wrong number of colors returned?
Duncan,
thanks for your feedback. I just received your response after sending out
mine. You came to the same conclusion. Should I prepare a patch and send
it to you so that you can also have a look? Or view Bugzilla?
Best wishes,
Achim
On Thu, 23 Feb 2023, Duncan Murdoch wrote:
On 23/02/2023 4:36 a.m., Sigbert Klinke wrote:
Hi,
I would have expected that I get always 3 colors as result which is not
true:
hcl.colors(3, alpha=c(0, 0.5, 1)) # 3 colors
rainbow(3, alpha=c(0, 0.5, 1))# 3 colors
heat.colors(3, alpha=c(0, 0.5, 1))# 3 colors
terrain.colors(3, alpha=c(0, 0.5, 1)) # 6 colors
cm.colors(3, alpha=c(0, 0.5, 1)) # 6 colors
topo.colors(3, alpha=c(0, 0.5, 1))# 9 colors
R-Version and platform:
R version 4.2.2 Patched (2022-11-10 r83330) -- "Innocent and Trusting"
Copyright (C) 2022 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)
Bug or feature?
Looks like a bug to me, they should all be length 3. The reason it happens
in terrain.colors (I didn't look at the others) is that it breaks the range
into two parts, and relies on the number of values of the parameters in each
part to get the length, but passes the full alpha vector in:
terrain.colors <- function (n, alpha, rev = FALSE)
{
if ((n <- as.integer(n[1L])) > 0) {
k <- n%/%2
h <- c(4/12, 2/12, 0/12)
s <- c(1, 1, 0)
v <- c(0.65, 0.9, 0.95)
cols <- c(hsv(h = seq.int(h[1L], h[2L], length.out = k),
s = seq.int(s[1L], s[2L], length.out = k),
v = seq.int(v[1L], v[2L], length.out = k), alpha =
alpha),
hsv(h = seq.int(h[2L], h[3L], length.out = n - k + 1)[-1L],
s = seq.int(s[2L], s[3L], length.out = n - k + 1)[-1L],
v = seq.int(v[2L], v[3L], length.out = n - k + 1)[-1L],
alpha = alpha))
if(rev) rev(cols) else cols
} else character()
}
A bug fix would be to recycle alpha to the right length and only pass in
portions of it, e.g.
terrain.colors <- function (n, alpha, rev = FALSE)
{
if ((n <- as.integer(n[1L])) > 0) {
alpha <- rep_len(alpha, length.out = n)
k <- n%/%2
h <- c(4/12, 2/12, 0/12)
s <- c(1, 1, 0)
v <- c(0.65, 0.9, 0.95)
cols <- c(hsv(h = seq.int(h[1L], h[2L], length.out = k),
s = seq.int(s[1L], s[2L], length.out = k),
v = seq.int(v[1L], v[2L], length.out = k), alpha =
alpha[seq_len(k)]),
hsv(h = seq.int(h[2L], h[3L], length.out = n - k + 1)[-1L],
s = seq.int(s[2L], s[3L], length.out = n - k + 1)[-1L],
v = seq.int(v[2L], v[3L], length.out = n - k + 1)[-1L],
alpha = alpha[seq_len(n - k) + k]))
if(rev) rev(cols) else cols
} else character()
}
I'd guess the same sort of approach would fix cm.colors and topo.colors.
Duncan Murdoch
__
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__
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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Re: [R] Palettes {grDevices} - wrong number of colors returned?
On 23/02/2023 4:36 a.m., Sigbert Klinke wrote:
Hi,
I would have expected that I get always 3 colors as result which is not
true:
hcl.colors(3, alpha=c(0, 0.5, 1)) # 3 colors
rainbow(3, alpha=c(0, 0.5, 1))# 3 colors
heat.colors(3, alpha=c(0, 0.5, 1))# 3 colors
terrain.colors(3, alpha=c(0, 0.5, 1)) # 6 colors
cm.colors(3, alpha=c(0, 0.5, 1)) # 6 colors
topo.colors(3, alpha=c(0, 0.5, 1))# 9 colors
R-Version and platform:
R version 4.2.2 Patched (2022-11-10 r83330) -- "Innocent and Trusting"
Copyright (C) 2022 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)
Bug or feature?
Looks like a bug to me, they should all be length 3. The reason it
happens in terrain.colors (I didn't look at the others) is that it
breaks the range into two parts, and relies on the number of values of
the parameters in each part to get the length, but passes the full alpha
vector in:
terrain.colors <- function (n, alpha, rev = FALSE)
{
if ((n <- as.integer(n[1L])) > 0) {
k <- n%/%2
h <- c(4/12, 2/12, 0/12)
s <- c(1, 1, 0)
v <- c(0.65, 0.9, 0.95)
cols <- c(hsv(h = seq.int(h[1L], h[2L], length.out = k),
s = seq.int(s[1L], s[2L], length.out = k),
v = seq.int(v[1L], v[2L], length.out = k), alpha
= alpha),
hsv(h = seq.int(h[2L], h[3L], length.out = n - k +
1)[-1L],
s = seq.int(s[2L], s[3L], length.out = n - k +
1)[-1L],
v = seq.int(v[2L], v[3L], length.out = n - k +
1)[-1L],
alpha = alpha))
if(rev) rev(cols) else cols
} else character()
}
A bug fix would be to recycle alpha to the right length and only pass in
portions of it, e.g.
terrain.colors <- function (n, alpha, rev = FALSE)
{
if ((n <- as.integer(n[1L])) > 0) {
alpha <- rep_len(alpha, length.out = n)
k <- n%/%2
h <- c(4/12, 2/12, 0/12)
s <- c(1, 1, 0)
v <- c(0.65, 0.9, 0.95)
cols <- c(hsv(h = seq.int(h[1L], h[2L], length.out = k),
s = seq.int(s[1L], s[2L], length.out = k),
v = seq.int(v[1L], v[2L], length.out = k), alpha
= alpha[seq_len(k)]),
hsv(h = seq.int(h[2L], h[3L], length.out = n - k +
1)[-1L],
s = seq.int(s[2L], s[3L], length.out = n - k +
1)[-1L],
v = seq.int(v[2L], v[3L], length.out = n - k +
1)[-1L],
alpha = alpha[seq_len(n - k) + k]))
if(rev) rev(cols) else cols
} else character()
}
I'd guess the same sort of approach would fix cm.colors and topo.colors.
Duncan Murdoch
__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
