In this section, we're going to explore the functions provided by the d3.path function to directly define a path that can be drawn with D3.
Using d3.path to draw paths
Drawing using the path API
Creating paths directly with SVG is rather complex, and it involves writing statements like this:
<path d="
M 213.1,6.7
c -32.4-14.4-73.7,0-88.1,30.6
C 110.6,4.9,67.5-9.5,36.9,6.7
C 2.8,22.9-13.4,62.4,13.5,110.9
C 33.3,145.1,67.5,170.3,125,217
c 59.3-46.7,93.5-71.9,111.5-106.1
C 263.4,64.2,247.2,22.9,213.1,6.7
z" />
As we've already seen in earlier chapters, D3 hides most of this complexity behind path generators. Sometimes, though, you might need to create a path generator yourself, or you might want to be able to draw a path yourself...