D3时间尺度问题，计算项目位置

Question

I am working on a bars chart that has uses a time scale on the x axis.

Each bar represents a month so all the dates are setted as YYYY-MM and when I load the data i parse it with:

var parseDate = d3.time.format("%Y-%m").parse;

The issue is that how each month has a different amount of days, the some bars are closer that others instead of having all the same margin, as you can see on this screenshot:

Here you can find the code, http://tributary.io/inlet/8700564

Thanks

Answer 1

You have two options: either use an ordinal (category) scale for the x-axis, which will give all the bars the same width, or set the width of each bar individually based on the length of the month.

To figure out the length of the month, you can use d3 time intervals to do get the date of the start of the next month. Then the width is just the difference between the two dates' positions on the xScale, possibly adjusted by padding to give some space between the bars.

rect.attr("x", function(d){return xScale(d.date) + padding;})
    .attr("width", function(d){
              return xScale( d3.time.month.offset(d.date, 1) )
                   - xScale(d.date)
                   - 2*padding;
        });