Colors and styles

Color and opacity

For color definitions and conversions, you can use Colors.jl.

setcolor() and sethue() will apply a single solid or transparent color to new graphics.

setblend() will apply a smooth transition between two or more colors to new graphics.

setmesh() will apply a color mesh to new graphics.

The difference between the setcolor() and sethue() functions is that sethue() doesn't change alpha opacity (transparency), so you can change the hue without changing the current alpha opacity (transparency) value.

Named colors, such as "gold", or "lavender", can be found in Colors.color_names dictionary.

fontsize(8)
cols = sort(collect(Colors.color_names))
ncols = 15
nrows = convert(Int, ceil(length(cols) / ncols))
table = Table(nrows, ncols, 800/ncols, 800/nrows)
gamma = 2.2
for n in 1:length(cols)
    col = cols[n][1]
    r, g, b = sethue(col)
    box(table[n], table.colwidths[1], table.rowheights[1], :fill)
    luminance = 0.2126 * r^gamma + 0.7152 * g^gamma + 0.0722 * b^gamma
    (luminance > 0.5^gamma) ? sethue("black") : sethue("white")
    text(string(cols[n][1]), table[n], halign=:center, valign=:middle)
end

line endings

(To make the label stand out against the background, the luminance is calculated, then used to choose the label's color.)

Luxor.sethue — Function

sethue("black")
sethue(0.3, 0.7, 0.9)
setcolor(sethue("red")..., .2)

Set the color without changing opacity.

sethue() is like setcolor(), but we sometimes want to change the current color without changing alpha/opacity. Using sethue() rather than setcolor() doesn't change the current alpha opacity.

Line styles

There are set- functions for controlling subsequent lines' width, end shape, join behavior, and dash pattern:

for l in 1:3
    sethue("black")
    setline(20)
    setlinecap(["butt", "square", "round"][l])
    textcentred(["butt", "square", "round"][l], 80l, 80)
    setlinejoin(["round", "miter", "bevel"][l])
    textcentred(["round", "miter", "bevel"][l], 80l, 120)
    poly(ngon(Point(80l, 0), 20, 3, 0, vertices=true), :strokepreserve, close=false)
    sethue("white")
    setline(1)
    strokepath()
end

line endings

patterns = ["solid", "dotted", "dot", "dotdashed", "longdashed",
  "shortdashed", "dash", "dashed", "dotdotdashed", "dotdotdotdashed"]
setline(12)

table = Table(fill(20, length(patterns)), [50, 300])
text.(patterns, table[:, 1], halign=:right, valign=:middle)

for p in 1:length(patterns)
    setdash(patterns[p])
    pt = table[p, 2]
    line(pt - (150, 0), pt + (150, 0), :stroke)
end

dashes

To define more complicated dash patterns in Luxor, pass a vector to setdash().

dashes = [50.0,  # ink
          10.0,  # skip
          10.0,  # ink
          10.0   # skip
          ]
setdash(dashes)

function dashing()
    setline(8)
    setlinecap("butt")
    patterns = [10, 4, 50, 25, 14, 100]
    table = Table(fill(20, length(patterns)), [40, 325])
    for p in 1:length(patterns)
        setdash(patterns)
        pt = table[p, 2]
        text(string(patterns), table[p, 1], halign=:right, valign=:middle)
        line(pt - (150, 0), pt + (200, 0), :stroke)
        patterns = circshift(patterns, 1)
        pop!(patterns)
    end
end

dashing()

more dashes

Notice that odd-numbered patterns flip the ink and skip numbers each time through.

Luxor.setline — Function

setline(n)

Set the line width, in points.