PdfMeasurementScale class

A measurement calibration the editing UI carries: how many real-world units one PDF point represents, the unit label, and the display precision. Persisted in PdfEditingPreferences so a drawing's scale survives reopening the file.

Build one directly, or from a calibration gesture with PdfMeasurementScale.fromReference: the user draws a segment of known real length, and the scale is its real length divided by its page-space length.

Annotations

• @immutable

Constructors

PdfMeasurementScale({required double unitsPerPoint, required String unitLabel, String pageUnitLabel = 'in', String? areaUnitLabel, int precision = 100})

const

PdfMeasurementScale.fromReference({required double pointLength, required double realLength, required String unitLabel, String pageUnitLabel = 'in', String? areaUnitLabel, int precision = 100})

Calibrates from a reference segment of pointLength PDF points that represents realLength unitLabels. pageUnitLabel is the on-page reference unit the ratio is quoted against ('in', 'cm', 'mm').

factory

Properties

areaUnitLabel → String?

The area unit label, or null to default to unitLabel².

final

hashCode → int

The hash code for this object.

no setter, override

pageUnitLabel → String

The on-page reference unit the scale is quoted against - the left-hand side of the 1 <pageUnit> = N <unit> ratio ('in', 'cm', 'mm'). Defaults to inches, the traditional drawing-scale reference.

final

precision → int

The display precision passed to PdfNumberFormat (nearest 1 / precision).

final

ratioLabel → String

A short user-facing label, e.g. 1 in = 20 ft or 1 cm = 5 m, quoted against pageUnitLabel as the on-page reference unit.

no setter

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

unitLabel → String

The distance unit label ('ft', 'm', ...).

final

unitsPerPoint → double

Real-world units per PDF point.

final

Methods

encode() → String

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toMeasure() → PdfMeasure

The /Measure dictionary model this scale stamps onto annotations.

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

override

Static Methods

decode(String source) → PdfMeasurementScale?

fromMeasure(PdfMeasure measure) → PdfMeasurementScale

Recovers a scale from a document-borne PdfMeasure (a page /VP viewport's /Measure, or an annotation's), so the editor can adopt the drawing scale a reopened or shared file already carries. The on-page reference unit isn't stored in /Measure, so it defaults to inches.