| ### ------ hcl() explorations |
| |
| hcl.wheel <- |
| function(chroma = 35, lums = 0:100, hues = 1:360, asp = 1, |
| p.cex = 0.6, do.label = FALSE, rev.lum = FALSE, |
| fixup = TRUE) |
| { |
| ## Purpose: show chroma "sections" of hcl() color space; see ?hcl |
| ## ---------------------------------------------------------------------- |
| ## Arguments: chroma: can be vector -> multiple plots are done, |
| ## lums, hues, fixup : all corresponding to hcl()'s args |
| ## rev.lum: logical indicating if luminance |
| ## should go from outer to inner |
| ## ---------------------------------------------------------------------- |
| ## Author: Martin Maechler, Date: 24 Jun 2005 |
| |
| require("graphics") |
| stopifnot(is.numeric(lums), lums >= 0, lums <= 100, |
| is.numeric(hues), hues >= 0, hues <= 360, |
| is.numeric(chroma), chroma >= 0, (nch <- length(chroma)) >= 1) |
| if(is.unsorted(hues)) hues <- sort(hues) |
| if(nch > 1) { |
| op <- par(mfrow= n2mfrow(nch), mar = c(0,0,0,0), xpd = TRUE) |
| on.exit(par(op)) |
| } |
| for(i.c in 1:nch) { |
| plot(-1:1,-1:1, type="n", axes = FALSE, xlab="",ylab="", asp = asp) |
| ## main = sprintf("hcl(h = <angle>, c = %g)", chroma[i.c]), |
| text(0.4, 0.99, paste("chroma =", format(chroma[i.c])), |
| adj = 0, font = 4) |
| l.s <- (if(rev.lum) rev(lums) else lums) / max(lums) # <= 1 |
| for(ang in hues) { # could do all this using outer() instead of for()... |
| a. <- ang * pi/180 |
| z.a <- exp(1i * a.) |
| cols <- hcl(ang, c = chroma[i.c], l = lums, fixup = fixup) |
| points(l.s * z.a, pch = 16, col = cols, cex = p.cex) |
| ##if(do."text") : draw the 0,45,90,... angle "lines" |
| if(do.label) |
| text(z.a*1.05, labels = ang, col = cols[length(cols)/2], |
| srt = ang) |
| } |
| if(!fixup) ## show the outline |
| lines(exp(1i * hues * pi/180)) |
| } |
| invisible() |
| } |
| |
| ## and now a few interesting calls : |
| |
| hcl.wheel() # and watch it redraw when you fiddle with the graphic window |
| hcl.wheel(rev.lum= TRUE) # ditto |
| hcl.wheel(do.label = TRUE) # ditto |
| |
| |
| ## Now watch: |
| hcl.wheel(chroma = c(25,35,45,55)) |
| |
| hcl.wheel(chroma = seq(10, 90, by = 10), p.cex = 0.4) |
| hcl.wheel(chroma = seq(10, 90, by = 10), p.cex = 0.3, fixup = FALSE) |
| hcl.wheel(chroma = seq(10, 90, by = 10), p.cex = 0.3, rev.lum = TRUE) |
| if(dev.interactive()) # new "graphics window" -- to compare with previous : |
| dev.new() |
| hcl.wheel(chroma = seq(10, 90, by = 10), p.cex = 0.3, rev.lum = TRUE, fixup=FALSE) |
