Updating tickValues after axis scaling

[Janne Kurkinen]

I've done an Y axis scaling slider. It worked fine with ticks(50) and my custom implementation minor tick hiding... But even though Y axis range had equal amounts of positive and negative, sometimes zero was not drawn as a major tick.

After doing custom calculation of tick values, I noticed that when 'tickValues' is called again it does not replace the previous ticks but rather draws an another set of ticks.

How about an improvement that when tickValues() is called with new data, it would replace the previously drawn ticks?

If I'd just remove those ticks like so:

d3.selectAll('.focus .axis--y1 .tick').remove();
yAxis.tickValues(yTickValues);
d3.selectAll('.focus .axis--y1 .tick')
    .filter(function (d, i) { return !isMajorTick(i); })
    .classed("minor", true);

It doesn't work as the removal operation takes time...and implementing an event listener callback for chaining this these further operations would seem a too cumbersome solution.

[Mike Bostock]

Calling axis.tickValues does set the axis’ tick values, but this does not have an effect until you re-render the axis (or render a new axis). This behavior is true of any axis property. An axis doesn’t maintain a relationship with it’s rendered elements. Think of it more like a rubber stamp that you can apply (or re-apply) to an SVG G element.

So, if you want to set new tick values, you’d say:

yAxis.tickValues(yTickValues);
d3.select(".axis--y1").call(yAxis);

Or all in one go:

d3.select(".axis--y1").call(yAxis.tickValues(yTickValues));

This will exit old ticks and enter or update new ticks as appropriate. If you want to customize the tick appearance, you can do that after re-rendering the axis.

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