You can now specify the domain of the quadtree upon construction, such that you
can add points to the quadtree dynamically later. The quadtree example now also
shows how to do a quick rectangular search using the quadtree.
This commit adds a new static function for computing the extent (min and max) of
a scale's domain, simplifying the logic in the ticks functions and ensuring
standard behavior (such as repeated values). Also, the linear ticks function is
extracted for reuse by the pow scale.
I opted not to reverse the tick order for descending domains; this might be nice
but it doesn't seem required, so we might as well keep the code small.
There's already a tension parameter, and it seems reasonable to overload this
parameter (originally intended for cardinal splines) to also apply to bundle
splines. The new "bundle" interpolation is identical to "basis" interpolation;
the only difference is that the tension parameter is used to straighten the
basis spline.
The input to the layout is now an array of edges to bundle, rather than nodes.
This eliminates the need for an `outgoing` accessor, since the links are passed
to the bundle layout directly.
The svg line generator now supports a beta (straightening; bundle strength)
parameter. I haven't decided if this is the right place or the right name for
it, but it seems like a reasonable starting point. I'm not happy with the cos &
sin needed to produce radial lines (both here and for the diagonal projection in
other examples), but I don't have a good alternative yet.
This commit also tries to make the construction of the links from the layout
nodes a bit easier to follow. The previous code was used another intermediate
representation, and I think it's cleaner to construct the default format
expected by the layouts. However, there's still a good chunk of code required to
massage the JSON format into a node hierarchy and array of dependencies, so I'd
like to find a way to simplify that, too.
This way, people can play with superformulas if they want them, but we keep the
core library small. If we want to replace the default symbol implementation with
superformulas in the future, we can do that too. For now, be conservative.
This is useful when other modules want to register interpolators for
d3.interpolate without adding an explicit dependency to d3.core. The
interpolators are applied in reverse order, and the first one that returns
a function is used.
(This commit was authored by @jasondavies and cherry picked.)
If the tween function returns null, then no tween will be applied for the
specified element. The default tween function now returns null if the start and
end value are the same, thus avoiding redundant interpolation.
Mike Bostock
Jason Davies
Tommy Montgomery
vtstarin