{
const svg = d3.create("svg")
.attr("viewBox", [-padding, 0, width, width]);
svg.append("style")
.text(`circle.hidden { fill: #000; fill-opacity: 1; r: 1px; }`);
svg.append("g")
.call(xAxis);
svg.append("g")
.call(yAxis);
const cell = svg.append("g")
.selectAll("g")
.data(d3.cross(d3.range(columns.length), d3.range(columns.length)))
.join("g")
.attr("transform", ([i, j]) => `translate(${i * size},${j * size})`);
cell.append("rect")
.attr("fill", "none")
.attr("stroke", "#aaa")
.attr("x", padding / 2 + 0.5)
.attr("y", padding / 2 + 0.5)
.attr("width", size - padding)
.attr("height", size - padding);
cell.each(function([i, j]) {
d3.select(this).selectAll("circle")
.data(data)
.join("circle")
.attr("cx", d => x[i](d[columns[i]]))
.attr("cy", d => y[j](d[columns[j]]));
});
const circle = cell.selectAll("circle")
.attr("r", 3.5)
.attr("fill-opacity", 0.7)
.attr("fill", d => z(d.species));
cell.call(brush, circle);
svg.append("g")
.style("font", "bold 10px sans-serif")
.style("pointer-events", "none")
.selectAll("text")
.data(columns)
.join("text")
.attr("transform", (d, i) => `translate(${i * size},${i * size})`)
.attr("x", padding)
.attr("y", padding)
.attr("dy", ".71em")
.text(d => d);
return svg.node();
}
function brush(cell, circle) {
const brush = d3.brush()
.extent([[padding / 2, padding / 2], [size - padding / 2, size - padding / 2]])
.on("start", brushstarted)
.on("brush", brushed)
.on("end", brushended);
cell.call(brush);
let brushCell;
// Clear the previously-active brush, if any.
function brushstarted() {
console.log("brushstarted", brushCell === this);
if (brushCell !== this) {
d3.select(brushCell).call(brush.move, null);
brushCell = this;
}
}
// Highlight the selected circles.
function brushed([i, j]) {
if (d3.event.selection === null) return;
const [[x0, y0], [x1, y1]] = d3.event.selection;
circle.classed("hidden", d => {
return x0 > x[i](d[columns[i]])
|| x1 < x[i](d[columns[i]])
|| y0 > y[j](d[columns[j]])
|| y1 < y[j](d[columns[j]]);
});
}
// If the brush is empty, select all circles.
function brushended() {
if (d3.event.selection !== null) return;
circle.classed("hidden", false);
}
}
md`### Add small buffer around data`
x = columns.map(c => d3.scaleLinear()
// .domain(d3.extent(data, d => d[c])) // original
.domain(d3.extent(data, d => d[c]).map((d,i,a) => i == 0 ? d - .01 * (a[1] - a[0]) : d + .01 * (a[1] - a[0])) ) // capture extremes w/brush
.rangeRound([padding / 2, size - padding / 2]))
y = x.map(x => x.copy().range([size - padding / 2, padding / 2]))
z = d3.scaleOrdinal()
.domain(data.map(d => d.species))
.range(d3.schemeCategory10)
xAxis = {
const axis = d3.axisBottom()
.ticks(6)
.tickSize(size * columns.length);
return g => g.selectAll("g").data(x).join("g")
.attr("transform", (d, i) => `translate(${i * size},0)`)
.each(function(d) { return d3.select(this).call(axis.scale(d)); })
.call(g => g.select(".domain").remove())
.call(g => g.selectAll(".tick line").attr("stroke", "#ddd"));
}
yAxis = {
const axis = d3.axisLeft()
.ticks(6)
.tickSize(-size * columns.length);
return g => g.selectAll("g").data(y).join("g")
.attr("transform", (d, i) => `translate(0,${i * size})`)
.each(function(d) { return d3.select(this).call(axis.scale(d)); })
.call(g => g.select(".domain").remove())
.call(g => g.selectAll(".tick line").attr("stroke", "#ddd"));
}
// data = d3.csvParse(await FileAttachment("iris.csv").text(), d3.autoType)
import { data, columns } from "@pbogden/boston-housing-scatterplot-matrix"
//columns = data.columns.filter(d => d !== "species")
width = 954
size = (width - (columns.length + 1) * padding) / columns.length + padding
padding = 20
d3 = require("d3@5")
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