anyplotlib.CircleWidget#

class anyplotlib.CircleWidget(push_fn, *, cx, cy, r, color='#00e5ff', linewidth=2, show_handles=True, lock_center=False)[source]#

Bases: Widget

Draggable circle overlay widget for 2-D plots.

Parameters:

  • push_fn (Callable) – Update callback.

  • cx (float) – Center position in pixel/data coordinates.

  • cy (float) – Center position in pixel/data coordinates.

  • r (float) – Radius in pixel/data coordinates.

  • color (str, optional) – CSS colour for the circle outline. Default "#00e5ff".

  • linewidth (float, optional) – Outline stroke width in px. Default 2.

  • show_handles (bool, optional) – Draw the radius grab handle. Default True.

  • lock_center (bool, optional) –

    Pin cx, cy and let only the radius change. Default False.

    The centre is refused at HIT-TEST time, not corrected afterwards: a grab on the ring body is simply not a widget grab, so it falls through to the plot’s own pan and the hover cursor never promises a move. Enforcing it from Python instead — snapping the centre back when the drag settles — cannot work, because the JS drag recomputes the position from its own grab-time snapshot on every frame; the ring tracks the cursor for the whole drag and only jumps back on release.

    Use it when the centre is not a free parameter — a ring on a power spectrum is centred on the DC term, so a draggable centre is a control that can only ever be wrong, and one nudged off-centre silently corrupts every radius measured from it.