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<!DOCTYPE html> |
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<meta charset="utf-8"> |
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<style> |
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svg { |
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font: 10px sans-serif; |
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} |
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.background path { |
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fill: none; |
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stroke: #ddd; |
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shape-rendering: crispEdges; |
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} |
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.foreground path { |
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fill: none; |
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stroke: steelblue; |
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} |
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.brush .extent { |
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fill-opacity: .3; |
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stroke: #fff; |
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shape-rendering: crispEdges; |
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} |
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.axis line, |
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.axis path { |
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fill: none; |
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stroke: #000; |
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shape-rendering: crispEdges; |
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} |
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.axis text { |
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fill:black; |
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text-shadow: 0 1px 0 #fff, 1px 0 0 #fff, 0 -1px 0 #fff, -1px 0 0 #fff; |
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} |
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</style> |
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<body> |
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<script src="//d3js.org/d3.v4.min.js"></script> |
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<script> |
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var margin = {top: 30, right: 10, bottom: 10, left: 10}, |
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width = 960 - margin.left - margin.right, |
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height = 500 - margin.top - margin.bottom; |
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var x = d3.scalePoint().range([0, width]).padding(1), |
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y = {}; |
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var line = d3.line(), |
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axis = d3.axisLeft(), |
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background, |
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foreground; |
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var svg = d3.select("body").append("svg") |
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.attr("width", width + margin.left + margin.right) |
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.attr("height", height + margin.top + margin.bottom) |
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.append("g") |
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.attr("transform", "translate(" + margin.left + "," + margin.top + ")"); |
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d3.csv("cars.csv", function(error, cars) { |
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// Extract the list of dimensions and create a scale for each. |
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x.domain(dimensions = d3.keys(cars[0]).filter(function(d) { |
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return d != "name" && (y[d] = d3.scaleLinear() |
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.domain(d3.extent(cars, function(p) { return +p[d]; })) |
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.range([height, 0])); |
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})); |
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// Add grey background lines for context. |
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background = svg.append("g") |
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.attr("class", "background") |
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.selectAll("path") |
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.data(cars) |
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.enter().append("path") |
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.attr("d", path); |
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// Add blue foreground lines for focus. |
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foreground = svg.append("g") |
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.attr("class", "foreground") |
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.selectAll("path") |
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.data(cars) |
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.enter().append("path") |
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.attr("d", path); |
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// Add a group element for each dimension. |
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var g = svg.selectAll(".dimension") |
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.data(dimensions) |
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.enter().append("g") |
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.attr("class", "dimension") |
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.attr("transform", function(d) { return "translate(" + x(d) + ")"; }); |
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// Add an axis and title. |
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g.append("g") |
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.attr("class", "axis") |
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.each(function(d) { d3.select(this).call(axis.scale(y[d])); }) |
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.append("text") |
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.style("text-anchor", "middle") |
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.attr("y", -9) |
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.text(function(d) { return d; }); |
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// Add and store a brush for each axis. |
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g.append("g") |
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.attr("class", "brush") |
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.each(function(d) { |
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d3.select(this).call(y[d].brush = d3.brushY() |
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.extent([[-10,0], [10,height]]) |
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.on("brush", brush) |
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.on("end", brush) |
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) |
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}) |
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.selectAll("rect") |
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.attr("x", -8) |
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.attr("width", 16); |
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}); |
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// Returns the path for a given data point. |
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function path(d) { |
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return line(dimensions.map(function(p) { return [x(p), y[p](d[p])]; })); |
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} |
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// Handles a brush event, toggling the display of foreground lines. |
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function brush() { |
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var actives = []; |
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svg.selectAll(".brush") |
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.filter(function(d) { |
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y[d].brushSelectionValue = d3.brushSelection(this); |
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return d3.brushSelection(this); |
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}) |
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.each(function(d) { |
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// Get extents of brush along each active selection axis (the Y axes) |
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actives.push({ |
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dimension: d, |
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extent: d3.brushSelection(this).map(y[d].invert) |
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}); |
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}); |
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// Update foreground to only display selected values |
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foreground.style("display", function(d) { |
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return actives.every(function(active) { |
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return active.extent[1] <= d[active.dimension] && d[active.dimension] <= active.extent[0]; |
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}) ? null : "none"; |
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}); |
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} |
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</script> |