Axis linking

Axes on different plots can be linked so that zooming or panning one automatically updates the other. Links live entirely in the browser — no Python round-trip occurs on zoom/pan.

`plot.axis`

plot.axis is an accessor object. Attribute access on it returns a cached Axis proxy for the named Gladly axis.

x = plot.axis.xaxis_bottom   # bottom x axis
x = plot.axis.xaxis_top      # top x axis
y = plot.axis.yaxis_left     # left y axis
y = plot.axis.yaxis_right    # right y axis
c = plot.axis.amplitude      # color or filter axis (use the quantity kind name)

The same object is returned on every access for a given name:

plot.axis.xaxis_bottom is plot.axis.xaxis_bottom   # True

This identity stability is required for link_axes to store and track links correctly.

Available spatial axis names

Name	Position
`xaxis_bottom`	Bottom horizontal axis
`xaxis_top`	Top horizontal axis
`yaxis_left`	Left vertical axis
`yaxis_right`	Right vertical axis

Color and filter axes use the quantity kind string as the axis name (e.g. plot.axis.frequency).

`gl.link_axes(axis1, axis2)` → `Link`

Link two axes bidirectionally. Both must be Axis proxy objects obtained from plot.axis.*.

link = gl.link_axes(plot1.axis.xaxis_bottom, plot2.axis.xaxis_bottom)

The two plots may be:

In the same PlotGroup
Displayed in different cells (independent widgets)
Displayed in any order — linking is resolved as soon as both plots have rendered

Linking is established purely in JS via Gladly’s linkAxes(). After the link is active, domain changes (zoom, pan) propagate directly between the two plot instances in the browser with no Python involvement.

Multiple links

link1 = gl.link_axes(p1.axis.xaxis_bottom, p2.axis.xaxis_bottom)
link2 = gl.link_axes(p2.axis.yaxis_left,   p3.axis.yaxis_left)

`link.unlink()`

Tear down a previously created link.

link = gl.link_axes(p1.axis.xaxis_bottom, p2.axis.xaxis_bottom)

# ... later:
link.unlink()

After unlink() is called, the Link object is spent and should not be used again.

Render-order independence

Links are registered in the browser via a module-level plot registry keyed by widget ID. When gl.link_axes(a, b) is called in Python, link records are written to both plots’ _links traits. In JS:

If both plots have already rendered → link established immediately.
If one has not rendered yet → the link is held as pending and resolved the moment the second plot registers itself.

You can call gl.link_axes() before or after display(), in any order.

Relationship to PlotGroup auto-linking

gl.link_axes() and PlotGroup(auto_link=True) are independent mechanisms:

auto_link links axes with matching quantity kinds automatically when a PlotGroup is created.
gl.link_axes() links any two specific axes explicitly, regardless of quantity kind, and does not require a PlotGroup.

Both can be used together.

`Axis` object

Axis objects are lightweight Python proxies. They carry:

Attribute	Description
`axis._plot`	The owning `Plot` widget
`axis._name`	The Gladly axis ID string
`axis._links`	List of active `Link` objects involving this axis

These are internal attributes; the public interface is plot.axis.<name> and gl.link_axes().

Axis linking

plot.axis