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 ReadonlylayerProtected ReadonlysupportsAbstract property that subclasses must implement to indicate extrema support
Protected ReadonlymovableProtected ReadonlyhighlighthighlightValues[row][col], or null for the whole trace when it
highlights nothing.
A single cell may also be null, meaning the chart drew no element
there. That is a narrower claim than the trace-wide null: the rest of
the grid still highlights, and only this position falls back to the
out-of-bounds state. A Google Charts calendar is the case it exists for
-- its first and last columns are ragged, so a handful of grid positions
have no rect at all while every other day does (#1174).
ProtectedxThe x axis's name, falling back to a generic one the layer authored none.
A getter rather than a field set in the constructor: the fallback is a translated word, and a trace outlives a language change — a name resolved once at construction would keep the language the chart was built in.
ProtectedyThe y axis's name, or a generic one. See xAxis.
ProtectedzThe z axis's name, or a generic one. See xAxis.
ProtectedisWhether 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.
ProtectedhighlightProtectedautoplayProtectedhasHow this layer names itself in the description dialog's layer tabs.
The producer's name when there is one, and the chart-type label
otherwise — the same fallback order TextService.layerIdentity uses for
the spoken layer-switch announcement, so a tab and the announcement single
out the same layer by the same name. The two differ only in register: the
announcement says "point plot" where the dialog says "Scatter Plot",
because that written form is what the dialog's own Chart Type line has
always shown and a tab sitting above it should agree with it.
Which way this chart is drawn, or undefined for a type that has no orientation to speak of.
Entering the chart already announces it -- "This is a maidr plot of type: horizontal bar" -- but the description dialog said only "Chart Type: Bar Chart", and for the box, violin and boxen families the orientation also silently reverses the order of the rows in the table underneath, because their constructors reverse the groups when the chart is horizontal. A reader comparing the table with what they walked had no way to know why the two disagreed.
Exposed here, and read once by the description service, rather than pushed
as a stat by each of the thirty-odd traces that has one. Named apart from
the bar and distribution families' own orientation fields, which hold the
declared* value and default it to vertical for every type -- including the
ones that have no orientation at all.
horizontal or vertical, or undefined when the type has no
orientation to report.
The 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.
ProtectedvaluesProtecteddimensionThe OHLC field the cursor is currently comparing.
Human-readable name of the reference line this layer compares against.
Number of matched (candle, reference) points in this layer.
ProtectedaudioProtectedbrailleProtectedtextRuns action with this element's observers muted.
A cursor move normally is the announcement -- moveToIndex notifies, and
everything downstream of it speaks, brailles and highlights. That is wrong
for a move the reader did not make and is not waiting to hear: the
description dialog's layer tabs relocate the reader in the chart while the
modal is open, and the trace's announcement would land in the same live
region the dialog is using, so one of the two is dropped. The caller
announces afterwards, once, when the reader is back on the chart.
Nesting is safe and the flag is restored on every path, including a throw, because a flag left raised would silence the chart for good.
The moves to make in silence
ProtectedgetGets 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.
Utility function to compare point values for rotor functionality
boolean value
ProtectedcompareRotor compare search along one row of numeric values.
Steps from the current column in the given direction and moves to the first value that satisfies the comparison; reports the rotor boundary when nothing further qualifies. For the traces whose values are a plain numeric grid indexed [row][col]; a trace with a richer layout (the bar's orientation-normalised rows, the candlestick's segments) keeps its own.
The values of the row being searched
Which way to search
Whether a lower or a higher value is sought
True when a matching value was found and moved to
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).
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
ProtectedgetResets 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, carrying only the axes the layer actually authored a label for. Subclasses should call this instead of constructing the axes object inline so charts without a real z dimension don't surface the placeholder default.
Every axis is gated, not just z. xAxis and yAxis fall back to the
literal 'X' and 'Y' when the JSON authors no label -- legal, and
common in adapter-generated specs -- and the dialog rendered that as
"X: X", a line that says nothing twice. The figure-level branch of the
description already showed only authored labels
(DescriptionService.getFigureAxes), so gating here is what makes
the two levels of the same dialog follow one rule.
Blankness is tested with trim(), the same rule named applies
when it decides whether to substitute the fallback in the first place. A
whitespace-only z label is truthy but blank, so the untrimmed guard used
to pass it through and then print the 'Level' placeholder the guard
existed to keep out.
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.
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
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
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.
Moves the cursor to a candle index without notifying observers. Used on activation to align the delta layer with the candle the user was on while preserving the x position across on/off toggles.
The candle index to position the cursor at
Computes 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
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 available X values for the Go To search combobox.
Array of X values in candle order
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
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").
Base implementation of navigation in HIGHER and LOWER modes of ROTOR, default is no-op Needs to be implemented in Line, Bar, Heatmap, Candlestick
Switches to the next OHLC field upward while the rotor is in a compare (above-line / below-line) mode. Without this override the rotor would fall back to the base class's throwing implementation and silently mirror a right move, jumping candles instead of changing field. Mirrors Candlestick.moveUpRotor: delegate to moveOnce, which handles its own boundary tone, and always report success so the rotor adds no competing message.
Always true (boundary handled by moveOnce)
Switches to the next OHLC field downward in a compare mode. See moveUpRotor.
Always true (boundary handled by moveOnce)
Always exposes the "on line" rotor filter unit, completing the fixed above-line / on-line / below-line trichotomy alongside the two compare units. It is intentionally NOT gated on a zero being present: gating on the current field made the unit flicker in and out as the user moved between OHLC fields, and gating on any field would silently hide the category for the (common) real-world case where no candle sits exactly on a moving average. A present-but-empty unit announces "no point on the line", which is the honest, predictable result — mirroring how the above/below compare units are always offered even when empty.
The on-line filter unit
Jumps to the previous/next candle whose current-field delta is exactly zero (on the reference line), preserving the current field. On-line filtering runs along the candle axis; the rotor service handles up/down (announcing them as unavailable) and dispatches only left/right here.
The active filter unit key
The direction to search
True if a matching candle was found and moved to
Protectedfind
Virtual (invisible) trace comparing a candlestick chart against a reference line (e.g. a moving average) from the same subplot.
Like a real candlestick, the user navigates left/right between candles and up/down between the four OHLC fields (value-sorted per candle, matching the candle's visual geometry). Each point exposes the signed delta
fieldValue - referencethrough the standard BTS pipeline:The layer has no SVG geometry of its own, so it never highlights, and it deliberately omits the volatility section a real candlestick exposes.