d3js.org是如何在主页上创建六边形网格的？

Question

在d3js.org上，他们拥有完全互动的六边形海洋，但是没有d3文档显示人们甚至会开始制作这样的东西。

从检查来源，您可以看到它是由一个名为hexbin和d3js本身的东西制成的，但是没有其他源代码可以帮助理解它是如何制作的。

有人能说明他们是如何实现这一目标的吗？

Answer 1

感谢Lars Kotthoff，假设你有一个名为data的结构，他们就这样做了：

data.forEach(function(d, i) {
  d.i = i % 10;
  d.j = i / 10 | 0;
});

Math.seedrandom(+d3.time.hour(new Date));

d3.shuffle(data);

var height = 460,
    imageWidth = 132,
    imageHeight = 152,
    radius = 75,
    depth = 4;

var currentFocus = [innerWidth / 2, height / 2],
    desiredFocus,
    idle = true;

var style = document.body.style,
    transform = ("webkitTransform" in style ? "-webkit-"
        : "MozTransform" in style ? "-moz-"
        : "msTransform" in style ? "-ms-"
        : "OTransform" in style ? "-o-"
        : "") + "transform";

var hexbin = d3.hexbin()
    .radius(radius);

if (!("ontouchstart" in document)) d3.select("#examples")
    .on("mousemove", mousemoved);

var deep = d3.select("#examples-deep");

var canvas = deep.append("canvas")
    .attr("height", height);

var context = canvas.node().getContext("2d");

var svg = deep.append("svg")
    .attr("height", height);

var mesh = svg.append("path")
    .attr("class", "example-mesh");

var anchor = svg.append("g")
      .attr("class", "example-anchor")
    .selectAll("a");

var graphic = deep.selectAll("svg,canvas");

var image = new Image;
image.src = "ex.jpg?3f2d00ffdba6ced9c50f02ed42f12f6156368bd2";
image.onload = resized;

d3.select(window)
    .on("resize", resized)
    .each(resized);

function drawImage(d) {
  context.save();
  context.beginPath();
  context.moveTo(0, -radius);

  for (var i = 1; i < 6; ++i) {
    var angle = i * Math.PI / 3,
        x = Math.sin(angle) * radius,
        y = -Math.cos(angle) * radius;
    context.lineTo(x, y);
  }

  context.clip();
  context.drawImage(image,
      imageWidth * d.i, imageHeight * d.j,
      imageWidth, imageHeight,
      -imageWidth / 2, -imageHeight / 2,
      imageWidth, imageHeight);
  context.restore();
}

function resized() {
  var deepWidth = innerWidth * (depth + 1) / depth,
      deepHeight = height * (depth + 1) / depth,
      centers = hexbin.size([deepWidth, deepHeight]).centers();

  desiredFocus = [innerWidth / 2, height / 2];
  moved();

  graphic
      .style("left", Math.round((innerWidth - deepWidth) / 2) + "px")
      .style("top", Math.round((height - deepHeight) / 2) + "px")
      .attr("width", deepWidth)
      .attr("height", deepHeight);

  centers.forEach(function(center, i) {
    center.j = Math.round(center[1] / (radius * 1.5));
    center.i = Math.round((center[0] - (center.j & 1) * radius * Math.sin(Math.PI / 3)) / (radius * 2 * Math.sin(Math.PI / 3)));
    context.save();
    context.translate(Math.round(center[0]), Math.round(center[1]));
    drawImage(center.example = data[(center.i % 10) + ((center.j + (center.i / 10 & 1) * 5) % 10) * 10]);
    context.restore();
  });

  mesh.attr("d", hexbin.mesh);

  anchor = anchor.data(centers, function(d) { return d.i + "," + d.j; });

  anchor.exit().remove();

  anchor.enter().append("a")
      .attr("xlink:href", function(d) { return d.example.url; })
      .attr("xlink:title", function(d) { return d.example.title; })
    .append("path")
      .attr("d", hexbin.hexagon());

  anchor
      .attr("transform", function(d) { return "translate(" + d + ")"; });
}

function mousemoved() {
  var m = d3.mouse(this);

  desiredFocus = [
    Math.round((m[0] - innerWidth / 2) / depth) * depth + innerWidth / 2,
    Math.round((m[1] - height / 2) / depth) * depth + height / 2
  ];

  moved();
}

function moved() {
  if (idle) d3.timer(function() {
    if (idle = Math.abs(desiredFocus[0] - currentFocus[0]) < .5 && Math.abs(desiredFocus[1] - currentFocus[1]) < .5) currentFocus = desiredFocus;
    else currentFocus[0] += (desiredFocus[0] - currentFocus[0]) * .14, currentFocus[1] += (desiredFocus[1] - currentFocus[1]) * .14;
    deep.style(transform, "translate(" + (innerWidth / 2 - currentFocus[0]) / depth + "px," + (height / 2 - currentFocus[1]) / depth + "px)");
    return idle;
  });
}