示例 8-1
function makeScales() {
var scX = d3
.scaleLinear()
.domain([0, 10])
.range([0, 300]);
var sc1 = d3
.scaleLinear()
.domain([0, 3, 10])
.range(["blue", "white", "red"]);
var sc2 = d3
.scaleLinear()
.domain([0, 5, 5, 10])
.range(["white", "blue", "red", "white"]);
var sc3 = d3
.scaleSequential(t => "" + d3.hsl(360 * t, 1, 0.5))
.domain([0, 10]);
// var sc4 = d3.scaleSequential( t => d3.interpolateSinebow(2*(1-t)/3) )
var sc4 = d3
.scaleSequential(t => d3.interpolateSinebow(2 / 3 - (3 * t) / 4))
.domain([0, 10]);
var sc5 = d3
.scaleSequential(
d3.interpolateRgbBasis(["#b2d899", "#ffffbf", "#bf9966", "#ffffff"])
)
.domain([0, 10]);
d3.select("#scale")
.append("g")
.call(colorbox, [300, 30], sc1)
.attr("transform", "translate(50,50)");
d3.select("#scale")
.append("g")
.call(colorbox, [300, 30], sc2)
.attr("transform", "translate(50,100)");
d3.select("#scale")
.append("g")
.call(colorbox, [300, 30], sc3)
.attr("transform", "translate(50,150)");
d3.select("#scale")
.append("g")
.call(colorbox, [300, 30], sc4)
.attr("transform", "translate(50,200)");
d3.select("#scale")
.append("g")
.call(colorbox, [300, 30], sc5, scX)
.attr("transform", "translate(50,250)");
}
function colorbox(sel, size, colors, ticks) {
//<1>
var [x0, x1] = d3.extent(colors.domain()); //<2>
var bars = d3.range(x0, x1, (x1 - x0) / size[0]);
var sc = d3
.scaleLinear()
.domain([x0, x1])
.range([0, size[0]]); //<3>
sel.selectAll("line")
.data(bars)
.enter()
.append("line") //<4>
.attr("x1", sc)
.attr("x2", sc)
.attr("y1", 0)
.attr("y2", size[1])
.attr("stroke", colors);
sel.append("rect")
.attr("width", size[0])
.attr("height", size[1]) //<5>
.attr("fill", "none")
.attr("stroke", "black");
if (ticks) {
//<6>
sel.append("g")
.call(d3.axisBottom(ticks))
.attr("transform", "translate( 0," + size[1] + ")");
}
}
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示例 8-2
function makeMandelbrot() {
var cnv = d3.select("#canvas"); //<1>
var ctx = cnv.node().getContext("2d");
var pxX = 465,
pxY = 250,
maxIter = 2000; //<2>
var scX = d3
.scaleLinear()
.domain([0, pxX])
.range([-1.31, -0.845]); //<3>
var scY = d3
.scaleLinear()
.domain([0, pxY])
.range([0.45, 0.2]);
var scC = d3
.scaleLinear()
.domain([1, 10, 23, 35, 55, 1999, 2000]) //<4>
.range([
"white",
"red",
"orange",
"yellow",
"lightyellow",
"white",
"darkgrey"
])
.clamp(true);
function mandelbrot(x, y) {
//<5>
var u = 0.0,
v = 0.0,
k = 0;
for (k = 0; k < maxIter && u * u + v * v < 4; k++) {
var t = u * u - v * v + x;
v = 2 * u * v + y;
u = t;
}
return k;
}
for (var j = 0; j < pxY; j++) {
//<6>
for (var i = 0; i < pxX; i++) {
var d = mandelbrot(scX(i), scY(j));
ctx.fillStyle = scC(d);
ctx.fillRect(i, j, 1, 1);
}
}
}
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示例 8-3
function makeContours() {
d3.json("/dataBase/haxby.json").then(function(scheme) {
//<1>
// Set up scales, including color
var pxX = 525,
pxY = 300; //<2>
var scX = d3
.scaleLinear()
.domain([-3, 1])
.range([0, pxX]);
var scY = d3
.scaleLinear()
.domain([-1.5, 1.5])
.range([pxY, 0]);
var scC = d3
.scaleSequential(d3.interpolateRgbBasis(scheme["colors"]))
.domain([-1, 1]); //<3>
var scZ = d3
.scaleLinear()
.domain([-1, -0.25, 0.25, 1])
.range(["white", "grey", "grey", "black"]);
// Generate data
var data = []; //<4>
var f = (x, y, b) =>
(y ** 4 + x * y ** 2 + b * y) * Math.exp(-(y ** 2));
for (var j = 0; j < pxY; j++) {
for (var i = 0; i < pxX; i++) {
data.push(f(scX.invert(i), scY.invert(j), 0.3));
}
}
var svg = d3.select("#contours"),
g = svg.append("g"); //<5>
var pathMkr = d3.geoPath(); //<6>
// Generate and draw filled contours (shading)
var conMkr = d3
.contours()
.size([pxX, pxY])
.thresholds(100); //<7>
g.append("g")
.selectAll("path")
.data(conMkr(data))
.enter()
.append("path")
.attr("d", pathMkr) //<8>
.attr("fill", d => scC(d.value))
.attr("stroke", "none");
// Generate and draw contour lines
conMkr = d3
.contours()
.size([pxX, pxY])
.thresholds(10); //<9>
g.append("g")
.selectAll("path")
.data(conMkr(data))
.enter()
.append("path")
.attr("d", pathMkr)
.attr("fill", "none")
.attr("stroke", d => scZ(d.value));
// Generate a single contour
g.select("g")
.append("path") //<10>
.attr("d", pathMkr(conMkr.contour(data, 0.025)))
.attr("fill", "none")
.attr("stroke", "red")
.attr("stroke-width", 2);
// Generate axis
svg.append("g")
.call(d3.axisTop(scX).ticks(10)) //<11>
.attr("transform", "translate(0," + pxY + ")");
svg.append("g").call(d3.axisRight(scY).ticks(5));
// Generate colorbox
svg.append("g")
.call(colorbox, [280, 30], scC) //<12>
.attr("transform", "translate( 540,290 ) rotate(-90)")
.selectAll("text")
.attr("transform", "rotate(90)");
svg.append("g")
.attr("transform", "translate( 570,10 )")
.call(
d3.axisRight(
d3
.scaleLinear()
.domain([-1, 1])
.range([280, 0])
)
);
});
}
function colorbox(sel, size, colors, ticks) {
//<1>
var [x0, x1] = d3.extent(colors.domain()); //<2>
var bars = d3.range(x0, x1, (x1 - x0) / size[0]);
var sc = d3
.scaleLinear()
.domain([x0, x1])
.range([0, size[0]]); //<3>
sel.selectAll("line")
.data(bars)
.enter()
.append("line") //<4>
.attr("x1", sc)
.attr("x2", sc)
.attr("y1", 0)
.attr("y2", size[1])
.attr("stroke", colors);
sel.append("rect")
.attr("width", size[0])
.attr("height", size[1]) //<5>
.attr("fill", "none")
.attr("stroke", "black");
if (ticks) {
//<6>
sel.append("g")
.call(d3.axisBottom(ticks))
.attr("transform", "translate( 0," + size[1] + ")");
}
}
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