Published
Edited
Apr 29, 2021
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showToolTip = (text, coords) => {
d3.select(".tooltip")
.text(text)
.style("top", coords[1] + "px")
.style("left", coords[0] + "px")
.style("visibility", "visible");
}
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//import {legend} from "@d3/legend-color"
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function legend({
color,
title,
tickSize = 6,
width = 320,
height = 44 + tickSize,
marginTop = 18,
marginRight = 0,
marginBottom = 16 + tickSize,
marginLeft = 0,
ticks = width / 64,
tickFormat,
tickValues,
legendfont,
titlefont
} = {}) {

const svg = d3.create("svg")
.attr("width", width)
.attr("height", height)
.attr("viewBox", [0, 0, width, height])
.style("overflow", "visible")
.style("display", "block");

let tickAdjust = g => g.selectAll(".tick line").attr("y1", marginTop + marginBottom - height);
let x;

// Continuous
if (color.interpolate) {
const n = Math.min(color.domain().length, color.range().length);

x = color.copy().rangeRound(d3.quantize(d3.interpolate(marginLeft, width - marginRight), n));

svg.append("image")
.attr("x", marginLeft)
.attr("y", marginTop)
.attr("width", width - marginLeft - marginRight)
.attr("height", height - marginTop - marginBottom)
.attr("preserveAspectRatio", "none")
.attr("xlink:href", ramp(color.copy().domain(d3.quantize(d3.interpolate(0, 1), n))).toDataURL());
}

// Sequential
else if (color.interpolator) {
x = Object.assign(color.copy()
.interpolator(d3.interpolateRound(marginLeft, width - marginRight)),
{range() { return [marginLeft, width - marginRight]; }});

svg.append("image")
.attr("x", marginLeft)
.attr("y", marginTop)
.attr("width", width - marginLeft - marginRight)
.attr("height", height - marginTop - marginBottom)
.attr("preserveAspectRatio", "none")
.attr("xlink:href", ramp(color.interpolator()).toDataURL());

// scaleSequentialQuantile doesn’t implement ticks or tickFormat.
if (!x.ticks) {
if (tickValues === undefined) {
const n = Math.round(ticks + 1);
tickValues = d3.range(n).map(i => d3.quantile(color.domain(), i / (n - 1)));
}
if (typeof tickFormat !== "function") {
tickFormat = d3.format(tickFormat === undefined ? ",f" : tickFormat);
}
}
}

// Threshold
else if (color.invertExtent) {
const thresholds
= color.thresholds ? color.thresholds() // scaleQuantize
: color.quantiles ? color.quantiles() // scaleQuantile
: color.domain(); // scaleThreshold

const thresholdFormat
= tickFormat === undefined ? d => d
: typeof tickFormat === "string" ? d3.format(tickFormat)
: tickFormat;

x = d3.scaleLinear()
.domain([-1, color.range().length - 1])
.rangeRound([marginLeft, width - marginRight]);

svg.append("g")
.selectAll("rect")
.data(color.range())
.join("rect")
.attr("x", (d, i) => x(i - 1))
.attr("y", marginTop)
.attr("width", (d, i) => x(i) - x(i - 1))
.attr("height", height - marginTop - marginBottom)
.attr("fill", d => d);

tickValues = d3.range(thresholds.length);
tickFormat = i => thresholdFormat(thresholds[i], i);
}

// Ordinal
else {
x = d3.scaleBand()
.domain(color.domain())
.rangeRound([marginLeft, width - marginRight]);

svg.append("g")
.selectAll("rect")
.data(color.domain())
.join("rect")
.attr("x", x)
.attr("y", marginTop)
.attr("width", Math.max(0, x.bandwidth() - 1))
.attr("height", height - marginTop - marginBottom)
.attr("fill", color);

tickAdjust = () => {};
}

svg.append("g")
.attr("transform", `translate(0,${height - marginBottom})`)
.call(d3.axisBottom(x)
.ticks(ticks, typeof tickFormat === "string" ? tickFormat : undefined)
.tickFormat(typeof tickFormat === "function" ? tickFormat : undefined)
.tickSize(tickSize)
.tickValues(tickValues))
.style("font-size",legendfont)
.call(tickAdjust)
.call(g => g.select(".domain").remove())
.call(g => g.append("text")
.attr("x", marginLeft)
.attr("y", marginTop + marginBottom - height - 6)
.attr("fill", "currentColor")
.attr("text-anchor", "start")
.attr("font-weight", "bold")
.style("font-size",titlefont)
.attr("class", "title")
.text(title));

return svg.node();
}
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function entity(character) {
return `&#${character.charCodeAt(0).toString()};`;
}
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function ramp(color, n = 256) {
const canvas = DOM.canvas(n, 1);
const context = canvas.getContext("2d");
for (let i = 0; i < n; ++i) {
context.fillStyle = color(i / (n - 1));
context.fillRect(i, 0, 1, 1);
}
return canvas;
}
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