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d3.js

Looking for a better way to alter the color of axis components in d3.js v4

I want to change the colour of an axis for a simple d3.js (v4) graph. The y axis in the following image is an example of the finished product;

enter image description here

I suspect that the method I am using to achieve this a bit ugly and I believe that there should be an alternative per the description below that I do not yet understand.

The axis component is a combination of text, path and line elements which require alteration of their respective styles (stroke and fill).

At this point the only method I have found to change the colour of the components is by individually setting styles in the <style> section of the code...

.axisRed line{
  stroke: red;
}

.axisRed path{
  stroke: red;
}

.axisRed text{
  fill: red;
}

...and applying that class to the y axis when appending it later in the JavaScript;

  svg.append("g")
      .attr("class", "axisRed")
      .call(d3.axisLeft(y));

Is there a way that I can apply these styles via .style("<some style>", "<some value>") lines while appending the y axis rather than declaring in the <style> section?

An example with code is here.

I have tried trying to address the individual DOM components such as the 'domain' class, but without success. I suspect that I do not understand the hierarchy of the axis component well enough.

Solution

  • On D3 you have several options to style the elements:

    Option A: Using style tag with your class:

    axisRed line{
  stroke: red;
}

.axisRed path{
  stroke: red;
}

.axisRed text{
  fill: red;
}
// apply applying that class to the y
 svg.append("g")
      .attr("class", "axisRed")
      .call(d3.axisLeft(y));

    Option B: Using style tag with auto-generate class:

    D3 assign domain class for the axis line, and inside a group 'g' for every tick class tick line and text. Without define a particular class:

    <style>
    path.domain  {
    stroke: red;
}
   .tick text {
    fill:blue
}
</style
.
.
 svg.append("g").call(d3.axisLeft(y));

// generate code 
<path class="domain" stroke="#000" d="M-6,450.5H0.5V0.5H-6"></path>
<g class="tick" opacity="1" transform="translate(0,414)">
      <line stroke="#000" x2="-6" y1="0.5" y2="0.5"></line>
      <text fill="#000" x="-9" y="0.5" dy=".32em">50</text>
</g>

    Option C:Inline at appening time

    On D3 V3 you could do a more compact:

    svg.append("line")
   .style({
      fill:"none",
      stroke:"#f00",
      "stroke-width":"10"
    })

    But on D3 V4, doesn't work. So I open a 'Issue': you can check and follow the progress here: https://github.com/d3/d3-selection/issues/82

    ** UPDATE ** On V4 you must include selection-multi:

    <script src="https://d3js.org/d3.v4.min.js"></script>
<script src="https://d3js.org/d3-selection-multi.v0.4.min.js"></script>

    and then use: styles intead style and attrs instead attr:

    svg.append("line")
   .styles({
      fill:"none",
      stroke:"#f00",
      "stroke-width":"10"
    })

    for your example:

    svg.selectAll(".domain")
   .styles({ fill:"none", stroke:"#f00",  "stroke-width":"1" });

    Now you got a compact way to style your elements

    Extra: you could style and attr any elements:

     var svg = d3.select("body").append("svg")
        .attrs({width:600, height:600})
        .styles({
             border:"1px",
            "border-style":"solid",
            "border-color":"#f00"})

    Here's the plunker