我们正在使用的平行坐标图以及该图的数据可在here中找到。此平行坐标图不适用于d3的版本4。我们已根据API从v3到v4进行了更改。我认为主要问题在于下面显示的画笔功能。
function brush() {
let actives = dimensions.filter(function (p) {
return d3.brushSelection(y[p]) !== null;
});
console.log(actives);
let extents = actives.map(function (p) {
return d3.brushSelection(y[p]);
});
foreground.style("display", function (d) {
return actives.every(function (p, i) {
return extents[i][0] <= d[p] && d[p] <= extents[i][1];
}) ? null : "none";
});
}
日志显示“ Array []”以显示活动内容。当前，我们将每个尺寸笔刷范围设置为[[-8,0]，[8，height]]，这可能也是一个问题。完整的代码在下面提供。
<!DOCTYPE html>
<meta charset="utf-8">
<style>
svg {
font: 10px sans-serif;
}
.background path {
fill: none;
stroke: #ddd;
shape-rendering: crispEdges;
}
.foreground path {
fill: none;
stroke: steelblue;
}
.brush .extent {
fill-opacity: .3;
stroke: #fff;
shape-rendering: crispEdges;
}
.axis line,
.axis path {
fill: none;
stroke: #000;
shape-rendering: crispEdges;
}
.axis text {
text-shadow: 0 1px 0 #fff, 1px 0 0 #fff, 0 -1px 0 #fff, -1px 0 0 #fff;
cursor: move;
}
</style>
<body>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
let margin = {top: 30, right: 10, bottom: 10, left: 10},
width = 960 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;
let x = d3.scalePoint().range([0, width]).padding(1),
y = {},
dragging = {};
let line = d3.line(),
axis = d3.axisLeft(), //Argument for axisLeft? Compare to code on original plot
background,
foreground;
let svg = d3.select("body").append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
d3.csv("cars.csv", function (error, cars) {
// Extract the list of dimensions and create a scale for each.
x.domain(dimensions = d3.keys(cars[0]).filter(function (d) {
return d !== "name" && (y[d] = d3.scaleLinear()
.domain(d3.extent(cars, function (p) {
return +p[d];
}))
.range([height, 0]));
}));
// Add grey background lines for context.
background = svg.append("g")
.attr("class", "background")
.selectAll("path")
.data(cars)
.enter().append("path")
.attr("d", path);
// Add blue foreground lines for focus.
foreground = svg.append("g")
.attr("class", "foreground")
.selectAll("path")
.data(cars)
.enter().append("path")
.attr("d", path);
// Add a group element for each dimension.
let g = svg.selectAll(".dimension")
.data(dimensions)
.enter().append("g")
.attr("class", "dimension")
.attr("transform", function (d) {
return "translate(" + x(d) + ")";
})
.call(d3.drag()
.subject(function (d) {
return {x: x(d)};
})
.on("start", function (d) {
dragging[d] = x(d);
background.attr("visibility", "hidden");
})
.on("drag", function (d) {
dragging[d] = Math.min(width, Math.max(0, d3.event.x));
foreground.attr("d", path);
dimensions.sort(function (a, b) {
return position(a) - position(b);
});
x.domain(dimensions);
g.attr("transform", function (d) {
return "translate(" + position(d) + ")";
})
})
.on("end", function (d) {
delete dragging[d];
transition(d3.select(this)).attr("transform", "translate(" + x(d) + ")");
transition(foreground).attr("d", path);
background
.attr("d", path)
.transition()
.delay(500)
.duration(0)
.attr("visibility", null);
}));
// Add an axis and title.
g.append("g")
.attr("class", "axis")
.each(function (d) {
d3.select(this).call(axis.scale(y[d]));
})
.append("text")
.style("text-anchor", "middle")
.attr("y", -9)
.text(function (d) {
return d;
});
// Add and store a brush for each axis.
g.append("g")
.attr("class", "brush")
.each(function (d) {
d3.select(this).call(y[d].brush = d3.brushY().extent([[-8,0],[8,height]]).on("start", brushstart).on("brush", brush));
})
.selectAll("rect")
.attr("x", -8)
.attr("width", 16);
});
function position(d) {
let v = dragging[d];
return v == null ? x(d) : v;
}
function transition(g) {
return g.transition().duration(500);
}
// Returns the path for a given data point.
function path(d) {
return line(dimensions.map(function (p) {
return [position(p), y[p](d[p])];
}));
}
function brushstart() {
d3.event.sourceEvent.stopPropagation();
}
// Handles a brush event, toggling the display of foreground lines.
function brush() {
//return !y[p].brush.empty was the original return value.
let actives = dimensions.filter(function (p) {
return d3.brushSelection(y[p]) !== null;
});
console.log(actives);
let extents = actives.map(function (p) {
return d3.brushSelection(y[p]);
});
foreground.style("display", function (d) {
return actives.every(function (p, i) {
return extents[i][0] <= d[p] && d[p] <= extents[i][1];
}) ? null : "none";
});
}
</script>
如果有人熟悉d3并可以提供任何指导，将不胜感激。我们还尝试在brush函数中使用d3.event.selection和y [p] .brush.selection。
最佳答案
我偶然发现了完全相同的问题，但在进行以下更改后设法解决了该问题。
通过以下方式为每个轴添加画笔：
y[d] = d3.scaleLinear().domain(d3.extent(data, function(p) {
return +p[d];
})).range([height, 0]);
y[d].brush = d3.brushY()
.extent([[-8, y[d].range()[1]], [8, y[d].range()[0]]])
.on('brush', brush);
随后，在添加画笔组时，将上面的内容作为画笔回调：
g.append('g')
.attr('class', 'brush')
.each(function(d) {
d3.select(this).call(y[d].brush);
})
.selectAll('rect')
.attr('x', -8)
.attr('width', 16);
最后，将画笔处理程序更改为：
function brush() {
const actives = [];
// filter brushed extents
svg.selectAll('.brush')
.filter(function(d): any {
return d3.brushSelection(this as any);
})
.each(function(d) {
actives.push({
dimension: d,
extent: d3.brushSelection(this as any)
});
});
// set un-brushed foreground line disappear
foreground.style('display', function(d) {
return actives.every(function(active) {
const dim = active.dimension;
return active.extent[0] <= y[dim](d[dim]) && y[dim](d[dim]) <= active.extent[1];
}) ? null : 'none';
});
}
如果上述方法令人困惑，请参阅以下独立示例，该示例帮助我正确地使用d3 v4刷了平行坐标：https://gist.github.com/kotomiDu/d1fd0fe9397db41f5f8ce1bfb92ad20d
关于javascript - D3 v4平行坐标图画笔选择，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/46591962/