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qu_line_styles

Every line style Qu draws.

catalog/qu_line_styles.qu

Five shapes and two adjectives, rather than a list of fifteen names to memorise: `dashed`, and `loose dashed` and `dense dashed` beside it. That composes the way the rest of Qu's word commands already do (`legend outside right`, `axis scale x log`), and density scales the GAPS only -- keeping the marks the same size is what makes `dense dashed` read as dashed packed tighter rather than as a fourth unrelated style.

Marks are defined in MILLIMETRES, not in multiples of the line width. A dash on a printed page is measured with a ruler, and Qu's canvas unit already is one (1/10 mm), so these lengths can be checked against the output directly. Width still has a say -- the pattern grows for a heavy stroke -- it just never shrinks into nothing for a hairline.

Run: qu run catalog/qu_line_styles.qu

Results

printed
wrote qu_line_styles.svg and .pdf
-14 -12 -10 -8 -6 -4 -2 0 0 2 4 6 8 10 12 14 loose solid solid dense solid loose dotted dotted dense dotted loose dashed dashed dense dashed loose dashdot dashdot dense dashdot loose dashdotdot dashdotdot dense dashdotdot Five shapes, three densities -5.0 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0 0.5 0 2 4 6 8 10 12 14 dashes = (20, 6) dashes = (2, 3, 2, 3, 12, 6) same pattern, dash_offset 0 and 9 dashed at width 0.6 dashed at width 3.0 (pattern grows) Custom patterns, offset, and weight
Drawn by running the program above.

The whole program

Runnable as it stands: qu run catalog/qu_line_styles.qu

# Every line style Qu draws.

#

# Five shapes and two adjectives, rather than a list of fifteen names to

# memorise: `dashed`, and `loose dashed` and `dense dashed` beside it. That

# composes the way the rest of Qu's word commands already do (`legend

# outside right`, `axis scale x log`), and density scales the GAPS only --

# keeping the marks the same size is what makes `dense dashed` read as

# dashed packed tighter rather than as a fourth unrelated style.

#

# Marks are defined in MILLIMETRES, not in multiples of the line width.

# A dash on a printed page is measured with a ruler, and Qu's canvas unit

# already is one (1/10 mm), so these lengths can be checked against the

# output directly. Width still has a say -- the pattern grows for a heavy

# stroke -- it just never shrinks into nothing for a hairline.

#

# Run:  qu run catalog/qu_line_styles.qu


theme("publication")
figure_size(4.6, 7.4, unit = "in")

x = linspace(0, 10, 400)

shapes    = ("solid", "dotted", "dashed", "dashdot", "dashdotdot")
densities = ("loose", "", "dense")

# ---- 1. the grammar: five shapes x three densities ----------------------

subplot(2, 1, 1)
row = 0
for si in 1 to 5 do
  for di in 1 to 3 do
    name = densities[di - 1] + " " + shapes[si - 1]
    plot(x, 0*x + row, style = name, color = "#222222")
    text(10.15, row, name)
    row = row - 1
  end for
end for
xlim(0, 14)
ylim(row + 0.5, 0.5)
title("Five shapes, three densities")
grid off

# ---- 2. custom patterns, and offset -------------------------------------

# `dashes = (...)` is the escape hatch: alternating on/off lengths in

# canvas units (1/10 mm), for anything the names do not cover.

subplot(2, 1, 2)
plot(x, 0*x + 0,  dashes = (20, 6),                 color = "#222222")
text(10.15, 0,  "dashes = (20, 6)")
plot(x, 0*x - 1,  dashes = (2, 3, 2, 3, 12, 6),     color = "#222222")
text(10.15, -1, "dashes = (2, 3, 2, 3, 12, 6)")
plot(x, 0*x - 2,  dashes = (14, 4), dash_offset = 0,  color = "#4477AA")
plot(x, 0*x - 2.3, dashes = (14, 4), dash_offset = 9, color = "#C0392B")
text(10.15, -2.15, "same pattern, dash_offset 0 and 9")
plot(x, 0*x - 3.3, style = "dashed", width = 0.6, color = "#222222")
text(10.15, -3.3, "dashed at width 0.6")
plot(x, 0*x - 4.3, style = "dashed", width = 3.0, color = "#222222")
text(10.15, -4.3, "dashed at width 3.0 (pattern grows)")
xlim(0, 14)
ylim(-5, 0.6)
title("Custom patterns, offset, and weight")
grid off

savefig("qu_line_styles.svg")
savefig("qu_line_styles.pdf")
print("wrote qu_line_styles.svg and .pdf")