#!/usr/bin/awk -f

This program is a copy of guff, a plot device. https://github.com/silentbicycle/guff

My copy here is written in awk instead of C, has no compelling benefit.

Public domain. @thingskatedid

Run as awk -v x=xyz ... or env variables for stuff?

Assumptions: the data is evenly spaced along the x-axis

TODO: moving average

TODO: trend lines, or guess at complexities

TODO: points vs. lines

TODO: colourblind safe scheme

TODO: center data around the 0 axis

TODO: scanning for all float formats input, including -inf, NaN etc

TODO: guess at whether to use lines or circles, based on delta within a window?

function hastitle() { for (i = 1; i <= NF; i++) { if ($i ~ /[^-0-9.]/) { return 1 } }

return 0

}

function amax(a, i, max) { max = -1

for (i in a) {
	if (max == -1 || a[i] > a[max]) {
		max = i
	}
}

return max

}

function normalise( delta) { for (i = 1; i <= NF; i++) { max[i] = 0 min[i] = 0

	for (j = 1; j <= NR; j++) {
		if (a[i, j] > max[i]) {
			max[i] = a[i, j]
		} else
		if (a[i, j] < min[i]) {
			min[i] = a[i, j]
		}
	}

	delta[i] = max[i] - min[i]

	for (j = 1; j <= NR; j++) {
		a[i, j] -= min[i]
		if (delta[i] > 0) {
			a[i, j] /= delta[i]
		}
	}
}

# TODO: rescale to center around 0

# Here the data is squished slightly in descending order of deltas.
# Each column is scaled independently anyway, so they're never to scale.
# The idea here is to help show intutively which are smaller, but without
# actually drawing them to size (since then very small deltas would not be
# visible at all).

k = 0
prev = -1

while (length(delta) > 0) {
	i = amax(delta)

	# Several columns can share the same delta
	# Formatting to %.3f here is just for sake of rounding
	if (prev != -1 && sprintf("%.3f", prev) != sprintf("%.3f", delta[i])) {
		k++
	}

	# +2 to squish things upwards a bit
	scale = (NF + 2 - k) / (NF + 2)

	# there's no need to scale by 1
	if (scale != 1) {
		for (j = 1; j <= NR; j++) {
			a[i, j] *= scale
		}
	}

	prev = delta[i]
	delete delta[i]
}

}

internal coordinates to svg coordinates

function point(x, y) { x = x * (chart_width - 2 * xmargin) + xmargin y = (height - 2 * ymargin) - y * (height - 2 * ymargin) + ymargin

return sprintf("%u,%u", x, y)

}

function line(i) { printf " <polyline stroke='%s%s' stroke-width='1.5' fill='none'", color[i], alpha printf " points='"

for (j = 1; j <= NR; j++) {
	printf "%s ", point((j - 1) / NR, a[i, j])
}

printf "'/>\n"

}

function circles(i) { for (j = 1; j <= NR; j++) { p = point((j - 1) / NR, a[i, j]) split(p, q, ",") printf " \n", q[1], q[2], color[i], alpha, color[i], alpha } }

function legend_text(i, title) { printf " \n", chart_width + gutter, i * line_height printf " \n", -10, -line_height / 2 + 5, color[i], color[i] printf " %-*s[%.3g, %.3g]\n", sprintf("fill: %s; font-size: %upx; font-family: mono", fg, font_size), (title_width > 0) ? title_width + 1 : 0, title, min[i], max[i] printf " \n" }

function display() { print "" printf "

title_width = 0
for (i = 1; i <= NF; i++) {
	if (length(title[i]) > title_width) {
		title_width = length(title[i])
	}
}

for (i = 1; i <= NF; i++) {

line(i)

	circles(i)
}

if (length(title)) {
	for (i = 1; i <= NF; i++) {
		legend_text(i, title[i])
	}
}

print "</svg>"

}

NR == 1 { if (hastitle()) { for (i = 1; i <= NF; i++) { title[i] = $i }

	NR--
	next
}

}

{ for (i = 1; i <= NF; i++) { a[i, NR] = $i } }

END { fg = "#eeeeee" alpha = "ff"

# Bang Wong's colour-safe palette, https://www.nature.com/articles/nmeth.1618
# (using just the last five colours)
color[3] = "#009E73"
color[2] = "#F0E442"
color[1] = "#0072B2"
color[4] = "#CC79A7"
color[5] = "#D55E00"

color[6] = fg

if (NF == 1) {
	color[1] = fg
}

if (NF > length(color)) {
	print "too many fields" >> "/dev/stderr"
	exit 1
}

chart_width=320
legend_width=300
height=120
xmargin=0
ymargin=5
gutter=30
font_size=15
line_height=20

# the data is scaled 0..1 for our internal coordinate space
normalise()

display()

}