ChartZoomState class - chart_zoom_state library

Constructors

ChartZoomState({double xStart = 0, double xEnd = 1, double velocityX = 0, double minWindowFraction = 0.02}): factory

Properties

breadcrumbs → List<String>: All breadcrumb labels from root to current level.
no setter
canPop → bool: True when there is zoom history to pop back to.
no setter
currentLabel → String?: Label of the current drill-down level (topmost history entry).
no setter
currentMetadata → Map<String, dynamic>: Metadata stored with the current drill-down entry.
no setter
depth → int: How many history levels deep we are (= drill-down depth).
no setter
hashCode → int: The hash code for this object.
no setteroverride
hasMomentum → bool: no setter
isIdentity → bool: True when showing the full data range.
no setter
minWindowFraction → double: Maximum allowed zoom ratio (visible fraction of data, e.g. 0.02 = 2%).
final
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited
velocityX → double: Current horizontal pan velocity (data-units per frame), used for fling.
final
windowSize → double: Current visible window size as a fraction of total data.
no setter
xEnd → double: Visible window end — normalised 0..1 fraction of full data range.
final
xStart → double: Visible window start — normalised 0..1 fraction of full data range.
final

Methods

advanceFling({double friction = 0.9}) → ChartZoomState: Advance one fling frame — decays velocity and applies pan.
canvasToFraction(double canvasX, double canvasWidth) → double: Convert a canvas x-pixel to a data fraction.
centreOn(double frac) → ChartZoomState: Pan to centre frac in the viewport.
drillDown(double start, double end, {required String label, Map<String, dynamic>? metadata}) → ChartZoomState: Push current state onto history and zoom to start..end.
endIndex(int dataLength) → int: Last visible data index.
fractionToCanvas(double frac, double canvasWidth) → double: Convert a data fraction to a canvas x-pixel.
fractionToIndex(double frac, int dataLength) → int: Convert a normalised fraction 0..1 to a data index in 0..dataLength-1.
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
panBy(double deltaFraction) → ChartZoomState: Pan by deltaFraction — positive = move viewport right (data moves left).
panTo(double frac) → ChartZoomState: Pan so that frac is at the left edge of the viewport.
pop() → ChartZoomState: Pop the most recent history entry, returning to the previous zoom level.
popAll() → ChartZoomState: Pop all history entries and return to full view.
reset() → ChartZoomState: Reset to full view without pushing history.
startIndex(int dataLength) → int: First visible data index.
toString() → String: A string representation of this object.
override
visibleCount(int dataLength) → int: Number of visible data points.
withVelocity(double vx) → ChartZoomState: Apply fling velocity.
withVisibleRange(double start, double end) → ChartZoomState: Replace the visible data fraction range without pushing history.
zoomAroundCanvas(double focalX, double canvasWidth, double scaleDelta, {bool pushHistory = false, String historyLabel = ''}) → ChartZoomState: Zoom centred on screen-relative position focalX in 0..canvasWidth.
zoomAroundFraction(double focalFraction, double scaleDelta, {bool pushHistory = false, String historyLabel = ''}) → ChartZoomState: Zoom so that [focalFraction - halfWindow .. focalFraction + halfWindow] is visible, where focalFraction is the pinch focal point in 0..1.
zoomToRange(double start, double end, {String label = 'Zoom'}) → ChartZoomState: Zoom to a specific data fraction range, pushing current state to history.

Operators

operator ==(Object other) → bool: The equality operator.
override

Constants

identity → const ChartZoomState