Creates a new ridgeline trace.
The MAIDR layer carrying one curve per group
Protected ReadonlyobserversProtectedisProtectedisTrue while AbstractTrace.getStateAt computes state at a temporarily moved cursor. Enforces (structurally, not just by documentation) that state getters never notify observers.
Protected ReadonlyidProtected ReadonlytypeProtected ReadonlytitleProtected ReadonlynameWhat this layer is, when the producer named it. See MaidrLayer.name.
Protected ReadonlyxProtected ReadonlyyProtected ReadonlyzProtected ReadonlynavigationProtected ReadonlylayerProtected ReadonlysupportsAbstract property that subclasses must implement to indicate extrema support
Protected ReadonlymovableProtected ReadonlyhighlightProtectedisWhether the cursor has no point to report.
Read from dimension rather than from any one trace's data,
because that is the one shape every trace already answers in. It is also
evaluated at the cursor — LineTrace returns the current series'
length as cols — so this covers a ragged layer, where one series has
points and another has none, and not only a layer that is empty
throughout.
True when there is nothing at (row, col) to describe
Gets the current state of the trace including audio, braille, text, and highlight information.
The current TraceState
ProtectedoutThe state pushed to observers when navigation leaves the data.
Declared as TraceEmptyState rather than the whole TraceState union
because that is what every implementation actually returns — the accessor
exists so AbstractPlot.notifyOutOfBounds has an empty state to
push. Narrowing it here is what lets the braille and highlight callers
hand the value straight on: those states accept the empty trace shape but
not a populated one, so a wider declaration would force each of them to
cast, and a cast is exactly what stops the compiler from noticing if an
override ever starts returning a populated state.
The empty trace state, positioned for out-of-bounds audio panning.
ProtectedhighlightProtectedautoplayProtectedhasThe trace's chart type. Lightweight alternative to reading
state.traceType, which eagerly computes the full audio/braille/text/
highlight state just to expose this one string.
ProtectedvaluesProtecteddimensionProtectedaudioProtectedbrailleProtectedtextProtectedgetGets safe row and column indices to prevent accessing undefined values
Object with safe row and column indices
Registers an observer to receive state updates.
The observer to add
Removes an observer from receiving state updates.
The observer to remove
Notifies all registered observers with the current state.
Notifies observers that an out-of-bounds condition occurred.
Base implementation of navigation in HIGHER and LOWER modes of ROTOR, default is no-op Needs to be implemented in Line, Bar, Heatmap, Candlestick
Utility function to compare point values for rotor functionality
boolean value
Returns true if this trace supports compare (lower/higher value) navigation. Override to false for trace types that don't use compare modes (e.g., scatter, which is all we currently have).
Returns the display name for the default data navigation mode. Override to provide a trace-specific name (e.g., "ROW AND COLUMN NAVIGATION" for scatter).
Returns the rotor's compare-mode labels and boundary-message nouns. Override to rename the two compare units for a trace-specific semantic (e.g., the candlestick delta layer uses "above line" / "below line").
Cleans up trace resources including values and highlighted SVG elements.
Only removes elements MAIDR created (hidden clones, synthetic markers); traces that highlight the chart's original live elements in place (e.g. heatmap cells, line dots) merely drop their references so the visible chart geometry survives focusout and live-data rebuilds.
Get all highlight SVG elements for this trace Used by HighlightService for high contrast mode
Array of all SVG elements, or empty array if none
Get all original (visible) SVG elements for this trace. These are the actual rendered elements, not the hidden clones used for highlighting. Used by HighlightService for high contrast mode color changes.
Array of all original SVG elements, or empty array if none
ProtectedgetComputes the trace state at an arbitrary position without moving the user's cursor or notifying observers. Used by monitor mode to sonify and announce a newly appended point while the user stays put.
The state getters read this.row/this.col internally, so the cursor
is moved temporarily and always restored in a finally block — this
method is the single owner of that pattern.
Re-entrancy hazard: this is only safe because the entire call chain is synchronous (no await points), so timers (e.g. autoplay ticks) cannot interleave before the finally-restore, and state getters never notify observers. If a getter ever becomes async or triggers notifications, callers could observe the temporary cursor.
The row of the position to compute state for
The column of the position to compute state for
The trace state at the requested position
Resets the trace to initial entry state
ProtectedgetReturns a human-readable label for this trace's chart type (e.g., 'Bar Chart', 'Scatter Plot') for display in the description modal. Falls back to the raw layer type if no mapping is registered.
ProtectedgetBuilds the axes object for the description state, including z only when the layer explicitly provides a z-axis label. Subclasses should call this instead of constructing the axes object inline so charts without a real z dimension don't surface the placeholder default.
Get available extrema targets for the current navigation context
Array of extrema targets that can be navigated to Default implementation returns empty array (no extrema support)
Base implementation for navigateToExtrema Subclasses must override to provide actual implementation
The extrema target to navigate to
ProtectedfinalizeCommon post-navigation cleanup that should be called by subclasses after they update their internal state
Returns true if this trace supports intersection navigation mode. Opt-in per trace type: override to return true (possibly conditionally, e.g. based on data shape) for trace types that expose point intersections between series. Intersection navigation is a trace-level capability — it has no meaning at the figure or subplot level, which is why it lives on AbstractTrace rather than AbstractPlot.
Returns true if this trace supports point-by-point navigation mode. Opt-in per trace type: override to return true for traces that expose individual data points navigable in reading order (left/right) and column-major order (up/down). Currently only ScatterTrace.
Move to the next point intersection (right arrow in intersection rotor mode). Default is a no-op returning false; subclasses that advertise supportsIntersectionMode must override to provide real behavior.
Move to the previous point intersection (left arrow in intersection rotor mode). Default is a no-op returning false; subclasses that advertise supportsIntersectionMode must override to provide real behavior.
Notifies the trace that the rotor is entering or leaving INTERSECTION_MODE. Default is a no-op; line-style traces don't need to track mode state because their state output is unchanged by the rotor mode. Traces whose audio/text output differs in intersection mode (e.g. ScatterTrace, which normally plays the whole x-column as a chord and must instead focus a single point) override this to flip an internal flag.
True when entering intersection mode, false when leaving.
Trace-specific rotor filter units appended to the rotor cycle after the built-in data/compare/grid/intersection modes. Each unit restricts navigation to points matching a predicate (e.g. only bullish candles). Default: none. Override to opt in (e.g. Candlestick exposes bullish/bearish/neutral units). The returned list is treated as read-only by the rotor service.
Moves within an active rotor filter unit along the filtered axis.
Called by RotorNavigationService when the current rotor mode is
one of this trace's getRotorFilterUnits. Filter units navigate a
single axis, so only left/right are dispatched here — the service
announces up/down as unavailable without calling the model (matching
intersection mode). Implementations should move to the nearest point
matching the unit identified by key and notify observers, returning
true; when no such point exists they should call notifyRotorBounds
and return false.
Default is a no-op that reports bounds, so a trace advertising a filter unit but forgetting to implement movement fails safe (announces "no point found") rather than moving unexpectedly.
The RotorFilterUnit.key of the active unit
The direction to search
True if the cursor moved, false otherwise
ProtectedupdateDefault implementation for updating visual point position Subclasses can override if they need custom positioning logic
Checks if this plot supports extrema navigation.
True if extrema navigation is supported
Base implementation for getting current X value Subclasses can override if they have different data structures
Moves to a specific X value in the trace.
The X value to navigate to
True if the move was successful, false otherwise
Gets the unique identifier for this trace.
The trace ID
Moves the active point to the pointer location and returns directional guidance toward the nearest data geometry in a single call.
Combining both operations avoids running findNearestPoint twice per
pointermove event — important on dense plots where the scan is the
hot path.
Screen-space x position of the pointer/finger
Screen-space y position of the pointer/finger
Guidance state relative to nearest point, or null when unavailable
ProtectedmoveMoves the trace to the nearest point when the pointer is within its bounds and the trace is not already focused on that point.
onCurve is intentionally non-optional: the caller has already paid
the cost of isPointInBounds to assemble guidance state, and
forcing subclasses to accept the value makes the contract explicit so a
future override cannot silently recompute (or worse, ignore) it.
Subclasses override this to customise hover-driven navigation:
Checks if the specified coordinates are within bounds of the element.
The x-coordinate
The y-coordinate
Object containing the SVG element and its position
True if the point is in bounds, false otherwise
Moves the cursor, holding the value when it changes group.
Along a curve the index is the position, so a horizontal move is the grid's own and ends whatever comparison was in progress. Between groups the index is not a position, because two groups need not share a sample grid -- so the group is stepped and the sample re-chosen as whichever sits nearest the value the reader is holding.
Which way to move
True if the cursor moved
Jumps to the first or last group, holding the value.
A vertical extreme is a vertical move and has the same problem: the base
grid carries the column index into the far group, and an index is not a
place on the value axis when the groups do not share a sample grid. This
is reachable from Ctrl+Up and Ctrl+Down, which are bound unconditionally
rather than gated on supportsExtrema -- that flag gates the statistical
extrema menu, not the grid-edge jump.
A horizontal extreme is the grid's own -- within a curve the index is the position -- and ends the comparison the same way a horizontal step does.
Which edge to jump to
True if the cursor moved
ProtectedfindFinds the group whose drawn curve is nearest a pointer position.
Horizontal pointer position
Vertical pointer position
The nearest sample, or null when nothing is resolvable
Trace implementation for ridgeline (joy) plots.
One density curve per group along a shared value axis, the curves offset down the page so their shapes can be compared.
ggridges, Plotly's ridgelines and the seaborn recipes all draw it.The offset is not data. A ridgeline's vertical stagger exists so the curves do not sit on top of one another; it says nothing about any group. A layer therefore carries each group's curve on its own terms -- the value it was measured at and the density there -- and never the baseline it happened to be drawn from. This is the same rule the area layer follows: read what the chart is of, not where it was put.
Two things follow, and they are what make this a type rather than a ViolinKdeTrace with a different layout.
Every group is pitched against the whole chart. The violin trace pitches from a reference curve and uses the current group only for volume, which suits a chart drawn to compare each violin against a first one. A ridgeline is drawn so a reader can ask which distribution is tallest, and where -- a question that needs one scale across all of them. Scaled per row, every group's own peak would be the highest note it can make and the chart would report a dozen equally tall ridges.
Moving between groups holds the value. Comparing at a fixed point on the value axis is what the chart is for, and it is the comparison a listener cannot make by holding a number in their head across a dozen groups. Groups are not obliged to share a sample grid -- a KDE evaluated over each group's own range does not -- so stepping to the next ridge by index lands at a different value, silently: every sample is a real density at a real place, and nothing in the announcement would give it away except the value itself, which is what changed.