Copyright 2016 Dean Attali. Licensed under the MIT license.
colourpicker gives you a colour picker widget that can be used in
different contexts in R.
The most common uses of colourpicker are to use the colourInput()
function to create a colour input, or to use the plotHelper()
function/RStudio Addin to easily select colours to use in a plot.
- Demos
- Installation
- Colour input for Shiny apps (or R markdown):
colourInput() - Select colours to use in your plot:
plotHelper() - Select colours to use in your R code:
colourPicker() - Features of
colourInput() - Features of
plotHelper()
- Click here to view a live interactive demo the colour input.
- The GIF below shows what the Plot Colour Helper looks like.
To install the stable CRAN version:
install.packages("colourpicker")
To install the latest development version from GitHub:
install.packages("devtools")
devtools::install_github("daattali/colourpicker")
library(shiny)
shinyApp(
ui = fluidPage(
colourInput("col", "Select colour", "purple"),
plotOutput("plot")
),
server = function(input, output) {
output$plot <- renderPlot({
set.seed(1)
plot(rnorm(50), bg = input$col, col = input$col, pch = 21)
})
}
)
To use this tool, either highlight code for a plot and select the addin
through the RStudio Addins menu, or call the plotHelper() function.
The colours selected will be available as a variable named CPCOLS.
The colour picker input is also available as an 'htmlwidgets' widget
using the colourWidget() function. This may not be terribly useful
right now since you can use the more powerful colourInput in Shiny
apps and Rmarkdown documents, but it may come in handy if you need a
widget.
Using colourInput is extremely trivial if you've used Shiny, and it's
as easy to use as any other input control. It was implemented to very
closely mimic all other Shiny inputs so that using it will feel very
familiar. You can add a simple colour input to your Shiny app with
colourInput("col", "Select colour", value = "red"). The return value
from a colourInput is an uppercase HEX colour, so in the previous
example the value of input$col would be #FF0000 (#FF0000 is the HEX
value of the colour red). The default value at initialization is white
(#FFFFFF).
Since most functions in R that accept colours can also accept the value
"transparent", colourInput has an option to allow selecting the
"transparent" colour. By default, only real colours can be selected, so
you need to use the allowTransparent = TRUE parameter. When this
feature is turned on, a checkbox appears inside the input box.
If the user checks the checkbox for "transparent", then the colour input
is grayed out and the returned value of the input is transparent. This
is the only case when the value returned from a colourInput is not a
HEX value. When the checkbox is unchecked, the value of the input will
be the last selected colour prior to selecting "transparent".
By default, the text of the checkbox reads "Transparent", but you can
change that with the transparentText parameter. For example, it might
be more clear to a user to use the word "None" instead of "Transparent".
Note that even if you change the checkbox text, the return value will
still be transparent since that's the actual colour name in R.
This is what a colour input with transparency enabled looks like
By default, the colour input's background will match the selected colour
and the text inside the input field will be the colour's HEX value. If
that's too much for you, you can customize the input with the
showColour parameter to either only show the text or only show the
background colour.
Here is what a colour input with each of the possible values for
showColour looks like
As with all other Shiny inputs, colourInput can be updated with the
updateColourInput function. Any parameter that can be used in
colourInput can be used in updateColourInput. This means that you
can start with a basic colour input such as
colourInput("col", "Select colour") and completely redesign it with
updateColourInput(session, "col", label = "COLOUR:", value = "orange",
showColour = "background", allowTransparent = TRUE, transparentText = "None")
This feature is available in shinyjs v0.0.8.0, which is currently only
on GitHub and not on CRAN.
If you want to only allow the user to select a colour from a specific
list of colours, rather than any possible HEX colour, you can use the
palette = "limited" parameter. By default, the limited palette will
contain 40 common colours, but you can supply your own list of colours
using the allowedCols parameter. Here is an image of the default
limited colour palette.
Specifying a colour to the colour input is made very flexible to allow
for easier use. When giving a colour as the value parameter of either
colourInput or updateColourInput, there are a few ways to specify a
colour:
- Using a name of an R colour, such as
red,gold,blue3, or any other name that R supports (for a full list of R colours, typecolours()) - If transparency is allowed in the
colourInput, the valuetransparent(lowercase) can be used. This will update the UI to check the checkbox. - Using a 6-character HEX value, either with or without the leading
#. For example, initializing acolourInputwith any of the following values will all result in the colour red:ff0000,FF0000,#ff0000. - Using a 3-character HEX value, either with or without the leading
#. These values will be converted to full HEX values by automatically doubling every character. For example, all the following values would result in the same colour:1ac,#1Ac,11aacc.
If you're worried that maybe someone viewing your Shiny app on a phone
won't be able to use this input properly - don't you worry. I haven't
quite checked every single device out there, but I did spend extra time
making sure the colour selection JavaScript works in most devices I
could think of. colourInput will work fine in Shiny apps that are
viewed on Android cell phones, iPhones, iPads, and even Internet
Explorer 8+.
The Plot Colour Helper is available as both a gadget and an RStudio addin. This means that it can be invoked in one of two ways:
- Highlight code for a plot and select the addin through the Addins menu, or
- Call the
plotHelper(code)function with plot code as the first parameter.
There is a small difference between the two: invoking the addin via
plotHelper() will merely return the final colour list as a vector,
while using the Addins menu will result in the entire plot code and
colour list getting inserted into the document.
The Plot Colour Helper lets you run code for a plot, and select a list
of colours. But how does the list of colours get linked to the plot? The
colour list is available as a variable called CPCOLS. This means that
in order to refer to the colour list, you need to use that variable in
your plot code. You can even refer to it more than once if you want to
select colours for multiple purposes in the plot:
plotHelper(ggplot(iris, aes(Sepal.Length, Petal.Length)) +
geom_point(aes(col = Species)) +
scale_colour_manual(values = CPCOLS[1:3]) +
theme(panel.background = element_rect(CPCOLS[4])),
colours = 4)
To more easily access the tool, you can call plotHelper() with no
parameters or select the addin without highlighting any code. In that
case, the default code in the tool will be initialized as
ggplot(iris, aes(Sepal.Length, Petal.Length)) +
geom_point(aes(col = Species)) +
scale_colour_manual(values = CPCOLS)
You can always change the plot code from within the tool.
You can set the initial colour list by providing a vector of colours as
the colours parameter to plotHelper() (eg.
plotHelper(colours = c("red", "#123ABC"))).
Alternatively, if you don't want to initialize to any particular set of
colours, but you want to initialize with a specific number of colours in
the list, you can provide an integer as the colours parameter (eg.
plotHelper(colours = 2)).
If the colour values are not provided, then a default palette of colours will be used for the initial colours. This palette has 12 colours, and if there are more than 12 colours to support then they will get recycled.
If you don't provide the colours parameter, or if you invoke the tool
as an addin, it will attempt to guess how many colours are needed. For
example, using the following plot code
ggplot(mtcars, aes(wt, mpg)) +
geom_point(aes(col = as.factor(am))) +
scale_colour_manual(values = CPCOLS)
will initialize the tool with 2 colours (because there are 2 am
levels), while the following code
ggplot(mtcars, aes(wt, mpg)) +
geom_point(aes(col = as.factor(cyl))) +
scale_colour_manual(values = CPCOLS)
will use 3 colours.
There are several keyboard shortcuts available, to make the selection process even simpler. Spacebar to add another colour, Delete to remove the currently selected colour, Left/Right to navigate the colours, and more. You can view the full list of shortcuts by clicking on Show keyboard shortcuts.
When the tool is run as an addin, the final colour list and the code get inserted into the currently selected RStudio document (either the Source panel or the Console panel).
If the tool is called with plotHelper(), then the return value is
simply the vector of selected colours. You can assign it into a variable
directly - running cols <- plotHelper() will assign the selected
colours into cols.
Since the plot code requires you to use the variable name CPCOLS,
after closing the plot helper tool, a variable named CPCOLS will be
available in the global environment.
The colours returned can either be in HEX format (eg. "#0000FF") or be named (eg. "blue") - you can choose this option inside the tool.
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