| Type: | Package |
| Title: | Fast Conversion of R Colors to Color Component Values and Native Packed Integer Format |
| Version: | 1.0.1 |
| Maintainer: | Mike Cheng <mikefc@coolbutuseless.com> |
| Description: | Color values in R are often represented as strings of hexadecimal colors or named colors. This package offers fast conversion of these color representations to either an array of red/green/blue/alpha values or to the packed integer format used in native raster objects. Functions for conversion are also exported at the 'C' level for use in other packages. This fast conversion of colors is implemented using an order-preserving minimal perfect hash derived from Majewski et al (1996) "A Family of Perfect Hashing Methods" <doi:10.1093/comjnl/39.6.547>. |
| License: | MIT + file LICENSE |
| URL: | https://github.com/coolbutuseless/colorfast |
| BugReports: | https://github.com/coolbutuseless/colorfast/issues |
| Encoding: | UTF-8 |
| RoxygenNote: | 7.3.2 |
| Suggests: | knitr, rmarkdown, testthat (≥ 3.0.0) |
| Config/testthat/edition: | 3 |
| VignetteBuilder: | knitr |
| NeedsCompilation: | yes |
| Packaged: | 2025-01-13 11:20:53 UTC; mike |
| Author: | Mike Cheng [aut, cre, cph] |
| Repository: | CRAN |
| Date/Publication: | 2025-01-13 11:50:02 UTC |
Fast conversion of colors-as-strings to an integer vector of packed RGBA values.
Description
Packed RGBA values are used in R's native raster objects.
Usage
col_to_int(col)
Arguments
col |
Character vector of color names. Supports all R color names (e.g. "red", "hotpink") and hex colors of the form: "#RRGGBBAA", "#RRGGBB", "#RGBA" and "#RGB". |
Value
Integer vector where the 4 bytes making up each integer represent the RGBA values of the color
Examples
col_to_int(c("hotpink", "#abc", "#abcd", "#aabb99", "#aabb9980"))
Fast conversion of colors-as-strings to a matrix of RGBA integers
Description
This is a faster replacement for grDevices::col2rgb() which uses
a hash lookup of R color names (rather than a linear search).
Usage
col_to_rgb(col)
Arguments
col |
Character vector of color names. Supports all R color names (e.g. "red", "hotpink") and hex colors of the form: "#RRGGBBAA", "#RRGGBB", "#RGBA" and "#RGB". |
Value
An integer matrix with four rows and number of columns the length of the input.
Examples
col_to_rgb(c("hotpink", "#abc", "#abcd", "#aabb99", "#aabb9980"))
Fast conversion of colors-as-packed-RGBA-integers to hexadecimal
Description
Packed RGBA values are used in R's native raster objects.
Usage
int_to_col(icol)
Arguments
icol |
Integer vector (where the 4 bytes making up each integer represent the RGBA values of the color) |
Value
Character vector
Examples
icols <- col_to_int(c("hotpink", "#abc", "#abcd", "#aabb99", "#aabb9980"))
int_to_col(icols)
Set alpha value of integer colors
Description
Set alpha value of integer colors
Usage
set_alpha(icol, alpha)
Arguments
icol |
Integer vector (where the 4 bytes making up each integer represent the RGBA values of the color) |
alpha |
numeric alpha value in range [0, 1]. Length of 1, or same length as 'col' |
Value
integer vector of colors with adjusted alpha channel
Examples
icol <- col_to_int('red')
icol
int_to_col(icol)
icol2 <- set_alpha(icol, 0.5)
int_to_col(icol2)